AATCC 16.3-2014
Developed in 1964 by AATCC Commit-tee RA50; revised 1971, 1974, 1978, 1981, 1982, 1990 (Supersedes AATCC Test Methods 16-1987, 16A-1988, 16C-1988, 16D-1988, 16E-1987, 16F-1988 and 16G-1985), 1993,2003, 2004, 2012 (Supersedes AATCC Test Method 16), 2014; reaffirmed 1977, 1998; editorial-ly revised 1983, 1984, 1986, 1995, 1996, 2009; Related to Option 3-ISO 105-B02.
1. Purpose and Scope
1.1 This test method provides the gen-eral principles and procedures for deter-mining the colorfastness to light of textile materials. The test options described are applicable to textile materials of all kinds and for colorants, finishes and treatments applied to textile materials. Test options included are:
1—Xenon-Arc Lamp, Alternate Light and Dark
2—Xenon-Arc Lamp, Continuous Light, Black Standard Option 3—Xenon-Arc Lamp, Continuous Light, Black Panel Option
1.2 The use of these test options does not imply, expressly or otherwise, an ac-celerated test for a specific application. The relationship between any lightfast-ness test and the actual exposure in use must be determined and agreed upon by the contractual parties.
1.3 This test method contains the follow-ing sections that assist in the use and im-plementation of the various options for de-termining lightfastness of textile materials.
Section Principle (2)
Terminology (3)
Safety Precautions (4)
Uses and Limitation (5)
Apparatus and Materials (6)
Comparison Standards (7)
Test Specimen Preparation (8)
Machine Operating Condition9, 18, 26 Calibration and V erification..10-11,
19-20,
27-28 AATCC Fading Unit Measurement......................12-13,
21, 29-30 Machine Exposure.................14-17, Procedures22-25,
31-34 Evaluation of Results.............35-39 Report (40)
Precision and Bias.................41-42 References..............................43Notes.. (44)
Appendix................................A Appendix................................B
2. Principle
2.1 Specimens of the textile material to
be tested and the agreed upon comparison
standard(s) are exposed simultaneously
to a light source under specified condi-
tions. The colorfastness to light of the
specimen is evaluated by comparison of
the color change of the exposed portion
to the masked control portion of the test
specimen or unexposed original material
using the Gray Scale for Color Change,
or by instrumental color measurement.
Lightfastness classification is accom-
plished by evaluation versus a simulta-
neously exposed series of AATCC Blue
Wool Lightfastness Standards.
3. Terminology
3.1 AATCC Blue Wool Lightfastness
Standard, n.—one of a group of dyed
wool fabrics distributed by AA TCC for
use in determining the amount of light
exposure of specimens during lightfast-
ness testing (see 44.1).
3.2 AATCC Fading Unit (AFU), n.—
a specific amount of exposure made un-
der the conditions specified in various
test methods where one AFU is one-
twentieth (1/20) of the light-on exposure
required to produce a color change equal
to Step 4 on the Gray Scale for Color
Change or 1.7 ± 0.3 CIELAB units of
color difference on AATCC Blue Wool
Lightfastness Standard L4.
3.3 black-panel thermo meter, n.—a
temperature measuring device, the sens-
ing unit of which is coated with black
paint designed to absorb most of the radi-
ant energy encountered in lightfastness
testing (see 44.2).
3.3.1 This device provides an estima-
tion of the maximum temperature a spec-
imen may attain during exposure to artifi-
cial light. Any deviation from the
geometry of this device described in 44.2
may have an influence on the measured
temperature.
3.4 black standard therm meter,
n.—a temperature measuring device, the
sensing unit of which is coated with black
material designed to absorb most of the
radiant energy encountered in lightfast-
ness testing and is thermally insulated by
means of a plastic plate (see 44.2).
3.4.1 This device provides an estima-
tion of the maximum temperature a spec-
imen may attain during exposure to artifi-
cial light. Any deviation from the
geometry of the device described in 44.2
may have an influence on the measured
temperature. The temperature measured
by the black standard thermometer will
not be the same as that measured by the
black-panel thermometer; therefore, they
cannot be used interchangeably.
3.5 broad bandpass radiometer, n.—
a relative term applied to radiometers that
have a bandpass width of more than 20
nm at 50% of maximum transmittance
and can be used to measure irradiance at
wavelengths such as 300-400 nm or 300-
800 nm.
3.6 color change, n.—as used in col-
orfastness testing, a change in color of
any kind whether a change in lightness,
hue or chroma or any combination of
these, discernible by comparing the test
specimen with a corresponding untested
specimen.
3.7 colorfastness, n.—the resistance of
a material to change in any of its color
characteristics, to transfer of its colo-
rant(s) to adjacent materials, or both as a
result of exposure of the material to any
environment that might be encountered
during the processing, testing, storage or
use of the material.
3.8 colorfastness to light, n.—the re-
sistance of a material to a change in its
color characteristics as a result of expo-
sure of the material to sunlight or an arti-
ficial light source.
3.9 infrared radiatio n, n.—radiant
energy for which the wavelengths of the
monochromatic components are greater
than those for visible radiation and less
than about 1 mm.
NOTE: The limits of the spectral range
of infrared radiation are not well defined
and may vary according to the user.
Committee E-2.1.2 of the CIE distin-
guishes in the spectral range between 780
nm and 1mm:
IR-A780-1400 nm
IR-B 1.4-3.0 μm
IR-C 3 μm to 1 mm
3.10 irradiance, n.—radiant power per
unit area incident on a receiver, typically
reported in watts per square meter, W/
(m2nm).
3.11 “L” designatio n, n.—the se-
quence number given each AA TCC Blue
Wool Lightfastness Standard according
to the number of AATCC Fading Units
required to produce a color change equal
to Step 4 on the Gray Scale for Color
Change.
AATCC Test Method 16.3-2014
Colorfastness to Light: Xenon-Arc
NOTE: See Table I for the numerical relationship between “L” designations of the standards and their colorfastness to light in AFUs. The colorfastness to light of a fabric specimen can be determined by comparing its color change after light exposure with that of the most similar AATCC Blue Wool Lightfastness Stan-dard as shown in Table II.
3.12 langley, n.—a unit of total solar radiation equivalent to one gram calorie per square centimeter of irradiated sur-face.
NOTE: The internationally recom-mended units are: Joule (J) for quantity of radiant energy, watt (W) for quantity of radiant power, and meter squared (m2) for area. The following factors are to be used: 1 langley = 1 cal/cm2; 1 cal/cm2 = 4.184 J/cm2 or 41840 J/m2.
3.13 lightfastness, n.—the property of
a material, usually an assigned number, depicting a ranked change in its color characteristics as a result of exposure of the material to sunlight or an artificial light source.
3.14 narro w bandpass radio meter, n.—a relative term applied to radiometers that have a bandpass width of 20 nm or less at 50% of maximum transmittance and can be used to measure irradiance at wavelengths such as 340 or 420, ± 0.5 nm.
3.15 photochromism, n.—a qualita-tive designation for a reversible change in color of any kind (whether a change in hue or chroma) which is immediately no-ticeable upon termination of light expo-sures when the exposed area of a speci-men is compared to the unexposed area. NOTE: The reversal of the color change or instability of the hue or chroma upon standing in the dark distinguishes photochromism from fading.
3.16 pyranometer, n.—a radiometer used to measure the global solar irradi-ance or, if inclined, hemispherical solar irradiance.
3.17 radiant po wer, n.—energy per unit time emitted, transferred or received as radiation.
3.18 radiometer, n.—an instrument used to measure radiant energy.
3.19 total irradiance, n.—radiant power integrated over all wavelengths at a point in time expressed in watts per square meter (W/m2).
3.20 ultraviolet radiation, n.—radiant energy for which the wavelengths of the monochromatic components are smaller than those for visible radiation and more than about 100 nm.
NOTE: The limits of the spectral range of ultraviolet radiation are not well de-fined and may vary according to the user. Committee E.2.1.2 of the CIE distin-guishes in the spectral range between 400 and 100 nm:
UV-A315-400 nm
UV-B280-315 nm
UV-C100-280 nm
3.21 visible radiation, n.—any radiant
energy capable of causing a visual sensa-
tion.
NOTE The limits of the spectral range
of visible radiation are not well defined
and may vary according to the user. The
lower limit is generally taken between
380 and 400 nm and the upper limit be-
tween 760 and 780 nm (1 nanometer, 1
nm = 10–9 m).
3.22 For definitions of other terms rel-
ative to lightfastness used in this test
method, refer to the Glossary of AATCC
Standard Terminology.
4. Safety Precautions
NOTE: These safety precautions are
for information purposes only. The pre-
cautions are ancillary to the testing proce-
dures and are not intended to be all inclu-
sive. It is the user’s responsibility to use
safe and proper techniques in handling
materials in this test method. Manufac-
turers MUST be consulted on specific de-
tails such as material safety data sheets
and other manufacturer’s recommenda-
tions. All OSHA standards and rules
must also be consulted and followed.
4.1 Do not operate the test equipment
until the manufacturer’s instructions have
been read and understood. It is the opera-
tor’s responsibility to conform to the
manufacturer’s directions for safe opera-
tion.
4.2 The test equipment contains high
intensity light sources. Do not look di-
rectly at the light source. The door to the
test chamber must be kept closed when
the equipment is in operation.
4.3 Before servicing light sources, al-
low 30 min for cool-down after lamp op-
eration is terminated.
4.4 When servicing the test equipment,
shut off both the off switch and the main
power disconnect switch. When
equipped, ensure that the main power in-
dicator light on the machine goes out.
4.5 Good laboratory practices should
be followed. Wear safety glasses in all
laboratory areas.
5. Uses and Limitation
5.1 Not all materials are affected
equally by the same light source and en-
vironment. Results obtained by the use of
any one test option may not be represen-
tative of those of any other test option or
any end-use application unless a mathe-
matical correlation for a given material
and/or a given application has been estab-
lished. Enclosed Carbon-Arc, Xenon-Arc
and Daylight have been extensively used
in the trade for acceptance testing of tex-
tile materials. There may be a distinct dif-
ference in spectral power distribution, air
temperature and humidity sensor loca-
tions, and test chamber size between test
equipment supplied by different manu-
facturers that can result in differences in
reported test results. Consequently, data
obtained from equipment supplied by the
different manufacturers, different test
chamber size, or different light source
and filter combinations cannot be used
interchangeably, unless a mathematical
correlation has been established. No cor-
relations among differently constructed
test apparatus are known to AATCC
Committee RA50.
5.2 Results from Xenon-Arc, for all
materials should be in good agreement
with the results obtained in Daylight Be-
hind Glass (see Table I). Since the spec-
tral distribution of Xenon-Arc, Alternate
Light and Dark, equipped with the speci-
fied filter glass is very close to that of av-
erage or typical daylight behind window
glass, it is expected that results should be
in good agreement with the results ob-
tained in Daylight, Daylight Behind
Glass.
5.3 When using this test method, the
test method option selected should incor-
porate light, humidity, and heat effects
based upon historical data and experi-
ence. The test method option selected
should also reflect expected end-use con-
ditions associated with the material to be
tested.
5.4 When using this test method, use a
standard of comparison which has a
known change in lightfastness after a spe-
cific exposure for comparison to the ma-
terial to be tested. AATCC Blue Wool
Lightfastness Standards have been used
extensively for this purpose.
Table I—AATCC Fading Unit and
Light Exposure Equivalents for
AATCC Blue Wool Lightfastness
Standards (see Section 41)a
AATCC
Blue Wool
Lightfastness
Standard
AATCC
Fading
Units
Xenon Only
kJ/(m2nm)
@420 nm
Xenon Only
kJ/(m2nm)
300-400 nm
L2
L3
L4
L5
L6
L7
L8
L9
5
10
20
40
80
160
320
640
21
43
85b
170
340b
680
1360
2720
864
1728
3456
6912
13824
27648
55296
110592
a For color change of Step 4 on the Gray Scale for
Color Change.
b Verified by experiment using Daylight Behind
Glass and Xenon-Arc, Continuous Light. All
other values are calculated (see Section 41).
6. Apparatus and Materials (see 44.3) 6.1 AATCC Blue Wool Lightfastness Standards L2 through L9 (see 44.1, 44.4 and 44.5).
6.2 L4 AATCC Blue Wool Standard of Fade for 20 AATCC Fading Units (AFU) (see 44.5).
6.3 L2 AATCC Blue Wool (alternate) Standard of Fade for 20 AATCC Fading Units (AFU) (see 11.2, 44.5).
6.4 Gray Scale for Color Change (AATCC Evaluation Procedure 1) (see 44.5).
6.5 Card stock: 163 g/m2 (90 lb) one ply, White Bristol Index.
6.6 Test masks made of material ap-proaching zero light transmittance, and suitable for multiple exposure levels, such as 10, 20, 40, etc. AFU.
6.7 Black-Panel Thermometer (see 3.3, 44.2).
6.8 Black Standard Thermometer (see 3.4, 44.2).
NOTE: The Black-Panel Thermometer should not be confused with the Black Standard Thermometer which is used in Xenon-Arc, Continuous Light, Option 2, and some European test procedures. Temperatures as measured by the two different devices generally will not agree at the same test condition. The term Black Thermometer, as used in this method, refers to either the Black Panel or Black Standard Thermometers.
6.9 Spectrophotometer or Colorimeter (see 43.2).
6.10 Xenon-Arc Lamp Fading Appara-tus optionally equipped with light moni-tors and control systems (see Appendix A and 44.6).
7. Comparison Standards
7.1 AATCC Blue Wool Lightfastness Standards, as defined in Method 16.3, are preferred for all options. However, the rate of fade of any AA TCC Blue Wool Lightfastness Standard by one test option may not agree with that of other test op-tions.
7.2 The reference standard can be any suitable textile material where a history of the rate of color change is known. Ref-erence standards for comparison must be determined and agreed upon by the con-tractual parties. Standards must be ex-posed simultaneously with the test speci-men. The use of the standard assists in determining time-to-time equipment and test procedure variations. If test results of the exposed standards differ by more than 10% from the known standard data, thor-oughly review the test equipment operating conditions, and correct any malfunctions or defective parts. Then, repeat the test.
8. Test Specimen Preparation
8.1 Number of Specimens—For accep-tance testing, use at least three replicate specimens of both the material to be
tested and the standard for comparison to
ensure accuracy unless otherwise agreed
upon between the purchaser and the sup-
plier.
8.2 Specimen Cutting and Mounting—
Identify each specimen using a label re-
sistant to the environment encountered
during the test. Mount in frames such that
the surface of the test specimen and the
reference specimen are the same distance
from the light source. Use covers that
avoid specimen surface compression,
particularly when testing pile fabrics. The
test specimen and the reference standards
shall be of equal size and shape. Cut and
prepare test specimens for exposure as
follows:
8.2.1 Specimen Backing—For all op-
tions, if the specimens do not have an in-
tegrated backing mount the specimens
and standards on white card stock. The
card stock shall be white, non-reflecting
cardboard. Consult the AATCC Buyer’s
Guide for information. When mounted
test specimens are masked, use test
masks approaching zero light transmit-
tance
8.2.2 Fabric—Cut swatches of fabric
with the long direction parallel to the ma-
chine (warp) direction, at least 70.0 ×
120.0 mm (2.75 × 4.7 in.) with the ex-
posed area measuring not less than 30.0 ×
30.0 mm (1.2 × 1.2 in.). Secure the
backed specimens in the frames supplied
with the test apparatus. Ensure that front
and back covers of the holders make
good contact with the specimens and give
a sharp line of demarcation between the
exposed and unexposed areas without
compressing the specimen unnecessarily
(see 44.7 and 44.8). When required to
prevent raveling, the specimens may be
edged by sewing, pinking or fusing.
8.2.3 Yarns—Wind or fasten yarns on
frames of white card stock to a length of
approximately 150.0 mm (6.0 in.). Only
that portion of the yarns directly facing
the radiant energy is evaluated for color
change. Wind the yarn on the frame
closely packed to at least 25.0 mm (1.0
in.) width. The control specimen must
contain the same number of strands as the
specimen subjected to exposure. After
the exposure has been completed, bind
together those yarns facing the light
source using 20.0 mm (0.75 in.) masking
or other suitable tape to keep the yarns
closely packed on the exposure frame for
evaluation (see 44.8).
Option 1
Xenon-Arc Lamp,
Alternate Light and Dark
Machine Operating Conditions
9. Preparation of Test Apparatus
9.1 Prior to running the test procedure,
verify machine operation by using the
following test protocol. To enhance the
repeatability of test results, install test ap-
paratus in a room where temperature and
relative humidity are controlled in accor-
dance with the manufacturer’s recom-
mendations.
9.2 Check to see that the machine has
been calibrated and maintained within the
manufacturer’s recommended calibra-
tion schedule interval.
9.3 Turn off all rack and specimen
spray units, if applicable.
9.4 Set machine operating conditions
as follows:
Light source Xenon
Alternate light/dark
(Light ON/OFF)
Black Standard
temperature70 ± 1oC (158 ± 2oF)
Chamber air temperature
Light cycle43 ± 2oC (110 ± 4oF)
Dark cycle43 ± 2oC (110 ± 4oF)
Relative Humidity%
Light cycle35 ± 5
Dark cycle90 ± 5
Light cycle hours
Light – ON 3.8
Light – OFF 1.0
Filter type See A3.3
Irradiance
W/m2/nm (at 420 nm) 1.10 ± 0.03
W/m2 at (300-400nm)48 ± 1
Water requirements (Input)
Type Demineralized,
distilled or reverse
osmosis
Solids ppm Less than 17, prefer-
ably less than 8
pH7 ± 1
Temperature Ambient 16 ± 5oC
(61 ± 9oF)
(See Appendix A.) Be sure that the tem-
perature chosen is appropriate for the
type of Black Thermometer to be used
(see 44.2). Fill the specimen rack with
framed white card stock and the required
black thermometer unit. The white card
stock is used to simulate air flow in the
test chamber during the test exposure and
should not include the actual test speci-
mens. Support the black thermometer
unit in the specimen drum or rack in the
same manner as the test specimen frames.
Operate and control the test apparatus as
described above and further defined by
the manufacturer. Operate the test appa-
ratus in this mode and adjust the instru-
mentation to provide the required black
panel or black standard temperature, cham-
ber air temperature and relative humidity.
When exterior indicators are not available,
read the black thermometer unit through
the window in the test chamber door.
9.5 Verify using AATCC Blue Wool
Lightfastness Standards following the
guidelines in 11.1-11.2.2. If the fade of
the L2 or L4 standards do not meet these
requirements follow the instrument man-
ufacturer’s instructions for calibration and repeat the 20 AFU exposure with fresh L2 or L4 standards. If the fade does meet the requirements described in Sec-tion 11, remove the white card stock from the specimen rack and proceed.
9.6 For additional information to pre-pare and operate the test apparatus refer to the manufacturer’s instructions and the following:
9.6.1 Test Standard ASTM G151 and G155 (see 43.4 and 43.5).
10.Calibration, Verification and AATCC
Fading Unit Measurement
10.1 Instrument Calibration—To en-sure standardization and accuracy, the in-struments associated with the exposure apparatus (that is, light monitor control system, Black Thermometers, chamber air sensor, humidity control system, UV sensors and radiometers) require periodic calibration. Whenever possible, calibra-tion shall be traceable to national or inter-national standards. Calibration schedule and procedure should be in accordance with manufacturer’s instructions.
10.1.1 The accuracy of machine opera-tion must be verified by exposure of an applicable AATCC Blue Wool Lightfast-ness Standard and assessment of the Standard after every 80-100 AATCC Fading Units. Always expose reference standards near the center position of the specimen rack adjacent to the black-panel temperature sensing unit.
11.Verification by AATCC Blue Wool
Lightfastness Standards
11.1 Expose the L4 AATCC Blue Wool Lightfastness Standard at the speci-fied temperature, humidity and operating conditions for 20 ± 2 continuous light-on operating hours. After exposure, assess the exposed standard specimen, either vi-sually or instrumentally. Increase or de-crease the wattage of the lamps, the time of exposure, of both, and expose addi-tional standard specimens until the change in color of the exposed standard meets one of the following criteria.
11.1.1 Visual Comparison—equals the change in color exhibited by the L4 Stan-dard of Fade applicable to the Lot desig-nation used.
11.1.2 Instrumental Color Measure-ment—Lot designations of AATCC Blue Wool Lightfastness Standard L4 equals the CIELAB units of color change speci-fied on the calibration certificate supplied with the standard as determined by AATCC Evaluation Procedure 6, Instru-mental Color Measurement.
11.2 Alternatively, the L2 AATCC Blue Wool Lightfastness Standard may be exposed at the specified temperature, humidity and selected conditions for 20 ±2 continuous light-on operating hours.After exposure, assess the exposed stan-
dard specimen, either instrumentally or
compare to a L2 Standard of Fade for 20
AFU. When required, increase or de-
crease the wattage of the lamps, or the
time of exposure, or both, and expose ad-
ditional standard specimens until the
change in color of the exposed standard
meets one of the following criteria.
11.2.1 Visual Comparison—equals the
change in color exhibited by the L2 Stan-
dard of Fade for 20 AFU applicable to the
Lot designation used (see 44.5).
11.2.2 Instrumental Color Measure-
ment—The performance of the Blue Wool
lot designations of AATCC Blue Wool
Lightfastness Standard L2 and L4 must
equal the CIELAB unit of color change
specified on the calibration certificate
supplied with the standard as determined
by AATCC Evaluation Procedure 6.
12.AATCC Fading Unit Measurement by
AATCC Blue Wool Lightfastness
Standards
12.1 The use of AATCC Blue Wool
Lightfastness Standards and AATCC
Fading Units provides a common expo-
sure standard across the various exposure
methods: daylight, carbon-arc lamp and
xenon-arc lamp. The terms clock hours
and machine hours are not valid reporting
methods.
12.2 Table I illustrates the number of
AATCC Fading Units to produce a color
change equal to Step 4 on the Gray Scale
for Color Change (see 43.1) or instru-
mentally (see 43.3) on each of the
AATCC Blue Wool Lightfastness Stan-
dards.
12.3 For instrumental color measure-
ment, the colorimetric data are calculated
using CIE 1964 10° observer data for Il-
luminant D
65
. Express the color differ-
ence in CIELAB units as directed in
AATCC Evaluation Procedure 6.
NOTE: For Xenon-Arc, Alternating
Light and Dark, Option 1, although cali-
bration is conducted using continuous
light-on operating hours, it may take
more or less operating hours during the
actual test cycle due to the inclusion of
the dark periods.
13.AATCC Fading Unit Measurement
based on Spectral Irradiation
13.1 The 20 AATCC Fading Units are
produced by an exposure interval of 85 kJ/
(m2nm) measured at 420 nm when xenon-
arc machines are operated at the conditions
specified in this test method (see Table I).
Machine Exposure Procedures
14.Machine Exposure, General
Conditions
14.1 Specimen Mounting. Mount the
test material on the specimen rack. Make
sure that all materials are adequately sup-
ported. Any displacement of the material
toward or away from the source, even by
a small distance, may lead to variation in
fading between specimens (see 8.2).
When alternate light and dark cycles are
required, begin exposure at the start of
the light cycle.
14.2 In the case of woven, knitted and
nonwoven fabrics, unless otherwise spec-
ified, ensure that the side normally used
as the face is directly exposed to the radi-
ant source.
14.3 Operate the test apparatus on a
daily basis until the selected exposure has
been completed. Avoid unnecessary de-
lays when interrupting the exposure pe-
riod to change filters, carbons or lamps,
as such delays may contribute to varia-
tions in results or lead to errors. When
available, monitor exposure test chamber
conditions with suitable recorders. If
necessary, readjust the controls to main-
tain the specified test conditions.
15.Machine Exposure to a Specified
Amount of Radiant Energy
15.1 One-Step Method—Expose the
test specimens and applicable standards
for 5, 10, 20 or multiples of 20 AATCC
Fading Units until the specimen has been
exposed to the desired amount of radiant
energy defined in terms of AATCC Fad-
ing Units measured by simultaneous ex-
posure of the appropriate Blue Wool
Standard(s).
15.2 Two-Step Method—Proceed as
directed in 15.1, except double the expo-
sure area of the test specimens. After the
specimen has been exposed to the first
specified level of radiant energy, remove
the specimens from the test chamber and
mask (cover) one-half of the exposed
area and continue the exposure for an ad-
ditional 20 or multiples of 20 AATCC
Fading Units until the specimen has been
exposed to the higher desired amount of
radiant energy.
15.3 In those machines equipped with
irradiation monitors, the AA TCC Fading
Units of exposure can be determined and
controlled by measuring kJ/(m2nm) at
420 nm (see Table I).
NOTE: The two-step method is pre-
ferred for the complete characterization
of the lightfastness of a test specimen.
16.Machine Exposure using a Reference
Specimen
16.1 Expose the test specimen(s) and
reference specimen(s) simultaneously to
the required end point in terms of
AATCC Fading Units, kilojoules per
square meter of irradiance or reference
specimen performance (that is, the refer-
ence specimen shows a color change
equal to Step 4 on the Gray Scale of
Color Change).
17.Machine Exposure for Lightfastness
Classification
17.1 One-Step Method—Expose test specimen(s) simultaneously with a series of AATCC Blue Wool Lightfastness Standards or determine the number of AATCC Fading Units required to pro-duce a color change in the test specimen equal to Step 4 on the Gray Scale for Color Change (see 44.10).
17.2 Two-Step Method—Proceed as directed in 17.1, except double the expo-sure area of the test specimens. After the specimen has been exposed to a color change equal to Step 4 on the Gray Scale for Color Change, remove the specimens from the test chamber and mask (cover) one-half of the exposed area and continue the exposure until the test specimen ex-hibits a color change equal to Step 3 on the Gray Scale for Color Change (see 44.10).
Option 2
Xenon-Arc Lamp, Continuous Light,
Black Standard Option
Machine Operating Conditions
18.Preparation of Test Apparatus
18.1 Prior to running the test proce-dure, verify machine operation by using the following test protocol. To enhance the repeatability of test results, install test apparatus in a room where temperature and relative humidity are controlled in accordance with the manufacturer’s rec-ommendations.
18.2 Check to see that the machine has been calibrated and maintained within the manufacturer’s recommended calibra-tion schedule interval.
18.3 Turn off all rack and specimen spray units, if applicable.
18.4 Set machine operating conditions as follows:
Light source Xenon
Continuous Light-on Black Standard
temperature60 ± 3oC (140 ± 8oF) Chamber air
temperature32 ± 5oC (90 ± 9oF) Relative
Humidity%30 ± 5
Filter type See A3.3 Irradiance W/m2/nm
(at 420nm) 1.25 ± 0.2 Irradiance W/m2
(300–400nm)65 ± 1
Water requirements (Input)
Type Demineralized,
distilled or reverse
osmosis
Solids ppm Less than 17, prefer-
ably less than 8 pH7 ± 1
Temperature Ambient 16 ± 5oC
(61 ± 9oF)(See Appendix A.) Be sure that the tem-
perature chosen is appropriate for the
type of Black Thermometer to be used
(see 44.2). Fill the specimen rack with
framed white card stock and the required
black thermometer unit. The white card
stock is used to simulate air flow in the
test chamber during the test exposure and
should not include the actual test speci-
mens. Support the black thermometer
unit in the specimen drum or rack in the
same manner as the test specimen frames.
Operate and control the test apparatus as
described above and further defined by
the manufacturer. Operate the test appa-
ratus in this mode and adjust the instru-
mentation to provide the required black
panel or black standard temperature,
chamber air temperature and relative hu-
midity. When exterior indicators are not
available, read the black thermometer
unit through the window in the test cham-
ber door.
18.5 Verify using AATCC Blue Wool
Lightfastness Standards following the
guidelines in 20.1-20.2.2. If the fade of
the L2 or L4 standards do not meet these
requirements follow the instrument man-
ufacturer’s instructions for calibration
and repeat the 20 AFU exposure with
fresh L2 or L4 standards. If the fade does
meet the requirements described in Sec-
tion 20 remove the white card stock from
the specimen rack and proceed.
18.6 For additional information to pre-
pare and operate the test apparatus refer
to the manufacturer’s instructions and the
following:
18.6.1 Test Standard ASTM G151 and
G155 (see 43.4 and 43.5).
19.Calibration, Verification and AATCC
Fading Unit Measurement
19.1 Instrument Calibration—To en-
sure standardization and accuracy, the in-
struments associated with the exposure
apparatus (that is, light monitor control
system, Black Thermometers, chamber
air sensor, humidity control system, UV
sensors and radiometers) require periodic
calibration. Whenever possible, calibra-
tion shall be traceable to national or inter-
national standards. Calibration schedule
and procedure should be in accordance
with manufacturer’s instructions.
19.1.1 The accuracy of machine opera-
tion must be verified by exposure of an
applicable AA TCC Blue Wool Lightfast-
ness Standard and assessment of the
Standard after every 80-100 AATCC
Fading Units. Always expose reference
standards near the center position of the
specimen rack adjacent to the black-panel
temperature sensing unit.
20.Verification by AATCC Blue Wool
Lightfastness Standards
20.1 Expose the L4 AATCC Blue
Wool Lightfastness Standard at the speci-
fied temperature, humidity and operating
conditions for 20 ± 2 continuous light-on
operating hours After exposure, assess
the exposed standard specimen, either vi-
sually or instrumentally. Increase or de-
crease the wattage of the lamps, the time
of exposure, of both, and expose addi-
tional standard specimens until the
change in color of the exposed standard
meets one of the following criteria.
20.1.1 Visual Comparison—equals the
change in color exhibited by the L4 Stan-
dard of Fade applicable to the Lot desig-
nation used.
20.1.2 Instrumental Color Measure-
ment—Lot designations of AATCC Blue
Wool Lightfastness Standard L4 equals
the CIELAB units of color change speci-
fied on the calibration certificate supplied
with the standard as determined by
AATCC Evaluation Procedure 6.
20.2 Alternatively, the L2 AATCC
Blue Wool Lightfastness Standard may
be exposed at the specified temperature,
humidity and selected conditions for 20 ±
2 continuous light-on operating hours.
After exposure, assess the exposed stan-
dard specimen, either instrumentally or
compare to a L2 Standard of Fade for 20
AFU. When required, increase or de-
crease the wattage of the lamps, or the
time of exposure, or both, and expose ad-
ditional standard specimens until the
change in color of the exposed standard
meets one of the following criteria.
20.2.1 Visual Comparison—equals the
change in color exhibited by the L2 Stan-
dard of Fade for 20 AFU applicable to the
Lot designation used (see 44.5).
20.2.2 Instrumental Color Measure-
ment—The performance of the Blue Wool
lot designations of AATCC Blue Wool
Lightfastness Standard L2 and L4 must
equal the CIELAB unit of color change
specified on the calibration certificate
supplied with the standard as determined
by AATCC Evaluation Procedure 6.
21.AATCC Fading Unit Measurement by
AATCC Blue Wool Lightfastness
Standards
21.1 The use of AATCC Blue Wool
Lightfastness Standards and AATCC
Fading Units provides a common expo-
sure standard across the various exposure
methods: daylight, carbon-arc lamp and
xenon-arc lamp. The terms clock hours
and machine hours are not valid reporting
methods.
21.2 Table I illustrates the number of
AATCC Fading Units to produce a color
change equal to Step 4 on the Gray Scale
for Color Change (see 43.1) or instru-
mentally (see 43.3) on each of the AA TCC
Blue Wool Lightfastness Standards.
21.3 For instrumental color measure-
ment, the colorimetric data are calculated
using CIE 1964 10° observer data for Il-luminant D 65. Express the color differ-ence in CIELAB units as directed in AATCC Evaluation Procedure 6.
NOTE: For Xenon-Arc, Alternating Light and Dark, Option 1, although cali-bration is conducted using continuous light-on operating hours, it may take more or less operating hours during the actual test cycle due to the inclusion of the dark periods.
Machine Exposure Procedures 22.Machine Exposure, General
Conditions
22.1 Specimen Mounting. Mount the test material on the specimen rack. Make sure that all materials are adequately sup-ported. Any displacement of the material toward or away from the source, even by a small distance, may lead to variation in fading between specimens (see 8.2).When alternate light and dark cycles are required, begin exposure at the start of the light cycle.
22.2 In the case of woven, knitted and nonwoven fabrics, unless otherwise spec-ified, ensure that the side normally used as the face is directly exposed to the radi-ant source.
22.3 Operate the test apparatus on a daily basis until the selected exposure has been completed. Avoid unnecessary de-lays when interrupting the exposure pe-riod to change filters, carbons or lamps,as such delays may contribute to varia-tions in results or lead to errors . When available, monitor exposure test chamber conditions with suitable recorders. If necessary, readjust the controls to main-tain the specified test conditions.23.Machine Exposure to a Specified
Amount of Radiant Energy
23.1 One-Step Method—Expose the test specimens and applicable standards for 5, 10, 20 or multiples of 20 AATCC Fading Units until the specimen has been exposed to the desired amount of radiant energy defined in terms of AA TCC Fad-ing Units measured by simultaneous ex-posure of the appropriate Blue Wool Standard(s).
23.2 Two-Step Method—Proceed as directed in 23.1, except double the expo-sure area of the test specimens. After the specimen has been exposed to the first specified level of radiant energy, remove the specimens from the test chamber and mask (cover) one-half of the exposed area and continue the exposure for an ad-ditional 20 or multiples of 20 AATCC Fading Units until the specimen has been exposed to the higher desired amount of radiant energy.
23.3 In those machines equipped with
irradiation monitors, the AATCC Fading Units of exposure can be determined and controlled by measuring kJ/(m 2nm) at 420 nm (see Table I).
NOTE: The two-step method is pre-ferred for the complete characterization of the lightfastness of a test specimen.24.Machine Exposure using a Reference
Specimen
24.1 Expose the test specimen(s) and reference specimen(s) simultaneously to the required end point in terms of AATCC Fading Units, kilojoules per square meter of irradiance or reference specimen performance (that is, the refer-ence specimen shows a color change equal to Step 4 on the Gray Scale of Color Change).
25.Machine Exposure for Lightfastness
Classification
25.1 One-Step Method—Expose test specimen(s) simultaneously with a series of AATCC Blue Wool Lightfastness Standards or determine the number of AATCC Fading Units required to pro-duce a color change in the test specimen equal to Step 4 on the Gray Scale for Color Change (see 44.10).
25.2 Two-Step Method—Proceed as directed in 25.1, except double the expo-sure area of the test specimens. After the specimen has been exposed to a color change equal to Step 4 on the Gray Scale for Color Change, remove the specimens from the test chamber and mask (cover)one-half of the exposed area and continue the exposure until the test specimen ex-hibits a color change equal to Step 3 on the Gray Scale for Color Change (see 44.10).
Option 3
Xenon-Arc Lamp, Continuous Light,
Black Panel Option Machine Operating Conditions 26.Preparation of Test Apparatus
26.1 Prior to running the test proce-dure, verify machine operation by using the following test protocol. To enhance the repeatability of test results, install test apparatus in a room where temperature and relative humidity are controlled in accordance with the manufacturer’s rec-ommendations.
26.2 Check to see that the machine has been calibrated and maintained within the manufacturer’s recommended calibra-tion schedule interval.
26.3 Turn off all rack and specimen spray units, if applicable.
26.4 Set machine operating conditions as follows:
Light source
Xenon
Continuous light-on
Black Panel temperature 63 ± 1oC (145 ± 2oF)Chamber air temperature 43 ± 2oC (110 ± 4oF)Relative
Humidity %30 ± 5Filter type See A3.3Irradiance
W/m2/nm (at 420nm) 1.10 ± 0.03W/m2 (at 300-400nm)48 ± 1Water requirements (Input)Type Demineralized,
distilled or reverse osmosis
Solids ppm Less than 17, prefer-ably less than 8pH 7 ± 1Temperature Ambient 16 ± 5oC
(61 ± 9oF)
(See Appendix A.) Be sure that the tem-perature chosen is appropriate for the type of Black Thermometer to be used (see 44.2). Fill the specimen rack with framed white card stock and the required black thermometer unit. The white card stock is used to simulate air flow in the test chamber during the test exposure and should not include the actual test speci-mens. Support the black thermometer unit in the specimen drum or rack in the same manner as the test specimen frames.Operate and control the test apparatus as described and further defined by the man-ufacturer. Operate the test apparatus in this mode and adjust the instrumentation to provide the required black panel or black standard temperature, chamber air temperature and relative humidity. When exterior indicators are not available, read the black thermometer unit through the window in the test chamber door.
26.5 Verify using AATCC Blue Wool Lightfastness Standards following the guidelines in 28.1-28.2.2. If the fade of the L2 or L4 standards do not meet these requirements follow the instrument man-ufacturer’s instructions for calibration and repeat the 20 AFU exposure with fresh L2 or L4 standards. If the fade does meet the requirements described in Sec-tion 28 remove the white card stock from the specimen rack and proceed.
26.6 For additional information to pre-pare and operate the test apparatus refer to the manufacturer’s instructions and the following:
26.6.1 Test Standard ASTM G151 and G155 (see 43.4 and 43.5).
27.Calibration, Verification and AATCC
Fading Unit Measurement
27.1 Instrument Calibration—To en-sure standardization and accuracy, the in-struments associated with the exposure apparatus (that is, light monitor control system, Black Thermometers, chamber
air sensor, humidity control system, UV sensors and radiometers) require periodic calibration. Whenever possible, calibra-tion shall be traceable to national or inter-national standards. Calibration schedule and procedure should be in accordance with manufacturer’s instructions.
27.1.1 The accuracy of machine opera-tion must be verified by exposure of an applicable AATCC Blue Wool Lightfast-ness Standard and assessment of the Standard after every 80-100 AATCC Fading Units. Always expose reference standards near the center position of the specimen rack adjacent to the black-panel temperature sensing unit.
28.Verification by AATCC Blue Wool
Lightfastness Standards
28.1 Expose the L4 AATCC Blue Wool Lightfastness Standard at the speci-fied temperature, humidity and operating conditions for 20 ± 2 continuous light-on operating hours. After exposure, assess the exposed standard specimen, either vi-sually or instrumentally. Increase or de-crease the wattage of the lamps, the time of exposure, of both, and expose addi-tional standard specimens until the change in color of the exposed standard meets one of the following criteria.
28.1.1 Visual Comparison—equals the change in color exhibited by the L4 Stan-dard of Fade applicable to the Lot desig-nation used.
28.1.2 Instrumental Color Measure-ment—Lot designations of AATCC Blue Wool Lightfastness Standard L4 equals the CIELAB units of color change speci-fied on the calibration certificate supplied with the standard as determined by AATCC Evaluation Procedure 6.
28.2 Alternatively, the L2 AATCC Blue Wool Lightfastness Standard may be exposed at the specified temperature, humidity and selected conditions for 20 ±2 continuous light-on operating hours. After exposure, assess the exposed stan-dard specimen, either instrumentally or compare to a L2 Standard of Fade for 20 AFU. When required, increase or de-crease the wattage of the lamps, or the time of exposure, or both, and expose ad-ditional standard specimens until the change in color of the exposed standard meets one of the following criteria.
28.2.1 Visual Comparison—equals the change in color exhibited by the L2 Stan-dard of Fade for 20 AFU applicable to the Lot designation used (see 44.5).
28.2.2 Instrumental Color Measure-ment—The performance of the Blue Wool lot designations of AATCC Blue Wool Lightfastness Standard L2 and L4 must equal the CIELAB unit of color change specified on the calibration certif-icate supplied with the standard as deter-mined by AA TCC Evaluation Procedure 6.29.AATCC Fading Unit Measurement by
AATCC Blue Wool Lightfastness
Standards
29.1 The use of AATCC Blue Wool
Lightfastness Standards and AATCC
Fading Units provides a common expo-
sure standard across the various exposure
methods: daylight, carbon-arc lamp and
xenon-arc lamp. The terms clock hours
and machine hours are not valid reporting
methods.
29.2 Table I illustrates the number of
AATCC Fading Units to produce a color
change equal to Step 4 on the Gray Scale
for Color Change (see 43.1) or instrumen-
tally (see 43.3) on each of the AATCC
Blue Wool Lightfastness Standards.
29.3 For instrumental color measure-
ment, the colorimetric data are calculated
using CIE 1964 10° observer data for Il-
luminant D65. Express the color differ-
ence in CIELAB units as directed in
AATCC Evaluation Procedure 6.
NOTE: For Xenon-Arc, Alternating
Light and Dark, Option 1, although cali-
bration is conducted using continuous
light-on operating hours, it may take
more or less operating hours during the
actual test cycle due to the inclusion of
the dark periods.
30.AATCC Fading Unit Measurement
Based on Spectral Irradiation
30.1 The 20 AATCC Fading Units are
produced by an exposure interval of 85
kJ(m2nm) measured at 420 nm when xe-
non-arc machines are operated at the con-
ditions specified in this test method (see
Table I).
Machine Exposure Procedures
31.Machine Exposure, General
Conditions
31.1 Specimen Mounting. Mount the
test material on the specimen rack. Make
sure that all materials are adequately sup-
ported. Any displacement of the material
toward or away from the source, even by
a small distance, may lead to variation in
fading between specimens (see 8.2).
When alternate light and dark cycles are
required, begin exposure at the start of
the light cycle.
31.2 In the case of woven, knitted and
nonwoven fabrics, unless otherwise spec-
ified, ensure that the side normally used
as the face is directly exposed to the radi-
ant source.
31.3 Operate the test apparatus on a
daily basis until the selected exposure has
been completed. Avoid unnecessary de-
lays when interrupting the exposure pe-
riod to change filters, carbons or lamps,
as such delays may contribute to varia-
tions in results or lead to errors. When
available, monitor exposure test chamber
conditions with suitable recorders. If
necessary, readjust the controls to main-
tain the specified test conditions. V erify
calibration of the test apparatus during
the test cycle.
32.Machine Exposure to a Specified
Amount of Radiant Energy
32.1 One-Step Method—Expose the
test specimens and applicable standards
for 5, 10, 20 or multiples of 20 AATCC
Fading Units until the specimen has been
exposed to the desired amount of radiant
energy defined in terms of AATCC Fad-
ing Units measured by simultaneous ex-
posure of the appropriate Blue Wool
Standard(s).
32.2 Two-Step Method—Proceed as
directed in 32.1, except double the expo-
sure area of the test specimens. After the
specimen has been exposed to the first
specified level of radiant energy, remove
the specimens from the test chamber and
mask (cover) one-half of the exposed
area and continue the exposure for an ad-
ditional 20 or multiples of 20 AATCC
Fading Units until the specimen has been
exposed to the higher desired amount of
radiant energy.
32.3 In those machines equipped with
irradiation monitors, the AA TCC Fading
Units of exposure can be determined and
controlled by measuring kJ/(m2nm) at
420 nm (see 30.1 and Table I).
NOTE: The two-step method is pre-
ferred for the complete characterization
of the lightfastness of a test specimen.
33.Machine Exposure using a Reference
Specimen
33.1 Expose the test specimen(s) and
reference specimen(s) simultaneously to
the required end point in terms of
AATCC Fading Units, kilojoules per
square meter of irradiance or reference
specimen performance (that is, the refer-
ence specimen shows a color change
equal to Step 4 on the Gray Scale of
Color Change).
34.Machine Exposure for Lightfastness
Classification
34.1 One-Step Method—Expose test
specimen(s) simultaneously with a series
of AATCC Blue Wool Lightfastness
Standards or determine the number of
AATCC Fading Units required to pro-
duce a color change in the test specimen
equal to Step 4 on the Gray Scale for
Color Change (see 44.10).
34.2 Two-Step Method—Proceed as
directed in 34.1, except double the expo-
sure area of the test specimens. After the
specimen has been exposed to a color
change equal to Step 4 on the Gray Scale
for Color Change, remove the specimens
from the test chamber and mask (cover)
one-half of the exposed area and continue
the exposure until the test specimen ex-hibits a color change equal to Step 3 on the Gray Scale for Color Change (see 44.10).
Evaluation of Results
35.Conditioning
35.1 After the test exposure is com-pleted, remove the test specimens and comparison standards from exposure.Condition in a dark room at standard con-ditions for testing textiles, as directed in ASTM D1776, Standard Practice for Conditioning and Testing Textiles, [65 ±2% RH and 21 ± 1°C (70 ± 2°F)] for a minimum of 4 h before evaluation.36.Assessment of Color Change
36.1 Compare the exposed portion to the masked control or to an unexposed original portion of the specimen (pre-ferred), as specified in a material specifi-cation or purchase order. Complete char-acterization of the lightfastness of a test specimen requires evaluation at more than one level of exposure. A difference in color between unexposed material and the masked portion of the exposed speci-men indicates that the textile has been af-fected by some agent other than light,such as heat or a reactive gas in the atmo-sphere. Although the exact cause of this difference in color may not be known, it should be noted in the report when it oc-curs.
36.2 Quantify the color change using either the AATCC Evaluation Procedure 1, Gray Scale for Color Change, or AATCC Evaluation Procedure 7, Instru-mental Assessment of the Change in Color of a Test Specimen, at the specified exposure level whether in AATCC Fad-ing Units, kilojoules of radiant energy, or compared to a reference standard (see 44.10).
36.3 Determine total color difference (ΔE CIELAB ) and the difference in lightness,chroma, and hue (ΔL *, ΔC *, ΔH *). Use instruments that provide values based on the CIE 1976 equation using illuminant D 65 and 10° observer data. For instru-ments with diffuse geometry, include the specular component of reflectance in the measurements (refer to AATCC Evalua-tion Procedure 6
37.Acceptance Based on Simultaneous
Exposure of a Reference Specimen
37.1 Assess color change of the mate-rial (not blue wool) as directed in Section 36 in terms of the agreed upon reference specimen.
37.2 Assess the lightfastness of the ma-terial as follows:
37.2.1 Satisfactory—If the test speci-men exhibits a color change equal to or
less than the reference specimen at the exposure level when the reference speci-men shows a color change equal to Step 4on the Gray Scale for Color Change.37.2.2 Unsatisfactory—If the test spec-imen exhibits a color change greater than the reference specimen at the exposure level when the reference specimen shows a color change equal to Step 4 on the Gray Scale for Color Change.
37.3 Alternatively, buyer and seller may make acceptance judgment based on color difference as described in 36.3.38.Classification Based on the AATCC
Blue Wool Lightfastness Standards (See Note 44.11)39.Classification above L7 AATCC Blue
Wool Lightfastness Standard (See Note 44.12)40.Report (See Table IV)
40.1 Reporting at the minimum should include the following information:a)Operator’s name and test date b)Specimen identification
c)Colorfastness to light rating/Light classification
d)Acceptance compared to reference specimen or masked area (Yes/No)
e)Colorfastness to light rating deter-mined by AA TCC Gray Scale or Instru-mentally
f)Classification method g)Reference standard
h)Temperature ambient (dry bulb) oC,black panel oC or black standard oC
i)Exposure controlled by: AATCC Blue Wool, radiant energy or other j)Total radiant energy
k)Type of apparatus, model no., serial no., manufacturer, specimen rack (in-clined, 2-tier, 3-tier or horizontal) and type of water supply l)Option employed
m)Elapsed exposures time
n)Mounting procedure (backed or un-backed)
o)Deviations from Test Method 16.3or the performance of the reference stan-dard, if any
Precision and Bias
41.Precision
41.1 Interlaboratory Test Summary—Committee RA50 has conducted exten-sive studies to evaluate the use of radia-tion monitoring devices to terminate ex-posures in lightfastness testing. Data has been collected in interlaboratory studies using controlled irradiance, xenon-arc equipment and in daylight exposures con-ducted during a two-year period in both Arizona and Southern Florida. In both studies, one laboratory conducted instru-mental measurement of the color change
for all exposed specimens.
The interlaboratory studies were un-dertaken, using eight different lightfast-ness standard fabrics, to determine the definition of 20 AATCC Fading Units in terms of measured radiation. These studies showed that acceptable agreement between laboratories can be obtained for lightfastness testing providing the follow-ing variables are controlled: irradiance level, black-panel temperature, ambient temperature and relative humidity. Over-all, there was less than 10% variability in the instrumentally determined color change of specimens exposed in different laboratories. For all specimens tested the standard deviation was equivalent to less than one-half step on the Gray Scale for Color Change. As a result of these tests,20 AA TCC Fading Units was established at 85 KJ/(m 2nm) when measured at 420nm (approximately 21.5 continuous light-on operating hr) when tested at the condi-tions specified for Xenon-Arc Lamp,Continuous Light, Option 3.
For the daylight studies, 16 different fabrics, in addition to AATCC and ISO Blue Wool Lightfastness standard fab-rics, were exposed. An exposure series was begun each quarter year at two loca-tions over a two-year period. Exposures were terminated based on instrumental measurement of radiant energy dosage. A wide variation in climatic conditions was encountered during the test period. The data obtained clearly shows that the color change of individual specimens is af-fected differently by variations in temper-ature, humidity, atmospheric contami-nants, etc.; however, the single most significant variable is radiation. The vari-ation in color change resulting from ex-posure during different years, locations,and seasons, averaged ± 30%.
A more detailed summary of these test results was presented to the 14th meeting of ISO, Technical Committee 38, Sub-committee 1 as Document 38/1 N 993,USA Report on Monitoring of Radiation during Lightfastness Testing.42.Bias
42.1 The colorfastness to natural and artificial light can be defined only in terms of a test method. There is no inde-pendent method for determining the true value. As a means of estimating this property, the method has no known bias.43.References
43.1 AATCC Evaluation Procedure 1,Gray Scale for Color Change (see 44.5).43.2 AATCC Evaluation Procedure 6,Instrumental Color Measurement (see 44.5).43.3 AATCC Evaluation Procedure 7,Instrumental Assessment of the Change in Color of a Test Specimen (see 44.5).43.4 ASTM G151, Standard Practice
for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Labo-ratory Light Sources (see 44.9).
43.5 ASTM G155, Standard Practice for Operating Xenon-Arc Light Apparatus for Exposure of Nonmetallic Materials (see 44.9).
44. Notes
44.1 Historically, AATCC Blue Wool Lightfastness Standards, except L2, were spe-cially prepared by blending varying propor-tions of wool dyed with a very fugitive dyestuff, Erio Chrome Azurole B (C.I. 43830) and wool dyed with a fast dyestuff, Indigosol Blue AGG (C.I. 73801). Each resultant higher numbered standard is twice as colorfast as the preceding numbered standard. AATCC Blue Wool Lightfastness Standards and the ISO numbered Blue Wool Lightfastness Standards (as used in ISO 105-B01) produce different ratings and therefore cannot be used inter-changeably. Lots 8 and 9 of the L2 AATCC Blue Wool Lightfastness Standard were batch dyed. L2 can be used to measure 5 or 20 AFU exposures, producing two distinct fading end-points. L2 Standards of Fade for 5 AFU and 20 AFU are available (see 44.5).
44.2 Black Thermometers are used to con-trol an artificial weathering device and to pro-vide an estimate of the maximum temperature of specimens exposed to a radiant energy source. There are two types of Black Ther-mometers. One type is referred to as a “Black Panel Thermometer” which is uninsulated and is made of metal. The other type is referred to as a “Black Standard Thermometer” which is insulated and is made of metal with a plastic backing. As a point of information, some ISO specifications specify the use of a “Black Standard Thermometer.” Typically, Black Standard Thermometers indicate higher tem-peratures than Black Panel Thermometers un-der the same exposure conditions.
The Black Thermometer units indicate the absorbed irradiance minus the heat dissipated by conduction and convection. Keep the black face of these thermometer units in good condi-tion. Follow the manufacturer’s recommenda-tions for proper care and maintenance of Black Thermometers.
44.2.1 For Black Panel Thermometers: Testing temperature is measured and regulated by a Black Panel Thermometer unit mounted on the specimen rack to permit the face of it to receive the same exposure as the test speci-men. Black Panel Thermometers shall consist of a metal panel at least 70 × 150 mm and not less than 45 × 100 mm whose temperature is measured with a thermometer or thermocou-ple whose sensitive portion is located in the center of and in good contact with the panel. The side of the panel facing the light source shall be black with a reflectance of less than 5% throughout the spectrum of light reaching the specimen; the side of the panel not facing the light source shall be open to the atmo-sphere within the exposure chamber.
44.2.2 For Black Standard Thermometers: Testing temperature is measured and regulated by a black standard thermometer unit mounted on the specimen rack to permit the face of it to receive the same exposure as the test speci-men. The Black Standard Thermometer shall consist of a plane of stainless steel plate mea-suring 70 × 40 mm with a thickness of about
0.5 mm, whose temperature is measured by a
thermal resistor, with good heat-conducting
properties, fitted to the reverse side. The metal
plate is fixed to a plastic plate so that it is ther-
mally insulated. The side of the panel facing
the light source shall be black with a reflec-
tance of less than 5% throughout the spectrum
of light reaching the specimen.
44.3 For potential equipment information
pertaining to this test method, please visit
the online AATCC Buyer’s Guide at http://
https://www.wendangku.net/doc/1118139005.html,/bg. AATCC provides the pos-
sibility of listing equipment and materials sold
by its corporate members, but AATCC does
not qualify, or in any way approve, endorse or
certify that any of the listed equipment or ma-
terials meets the requirements in its test methods.
44.4 More uniform and reproducible fading
of the AATCC Blue Wool Lightfastness Stan-
dards and test specimens is achieved when
backed with white cardboard. The color dif-
ference values in the initial determination of
the end point for the AATCC Blue Wool
Lightfastness Standards were determined from
exposures with such backing. Although toler-
ances are given for both the AATCC Blue
Wool Lightfastness Standards, every effort
should be made to achieve the midpoint value
given for these standards. For referee pur-
poses, the AATCC Blue Wool Lightfastness
Standards will be exposed in multiples of
three and the average color change must equal
the CIELAB unit of color change specified on
the calibration certificate supplied with the ap-
plicable standard as determined by AATCC
Evaluation Procedure 6 (see 44.5).
44.5 Available from AATCC, P.O. Box
12215, Research Triangle Park NC 27709; tel:
+1.919.549.8141; fax: +1.919.549.8933; web
site: https://www.wendangku.net/doc/1118139005.html,; e-mail: orders@https://www.wendangku.net/doc/1118139005.html,.
44.6 Refer to ASTM G151 and G155 for
guidance on design and performance require-
ments for instruments specified in this
method. Further guidance is found in Appen-
dix A. Consult the AATCC Buyer’s Guide for
potential equipment information.
44.7 Pile fabric, such as carpets, which
have fibers that may shift position, or texture
which may make evaluations in small areas
difficult should be tested with an exposed area
of not less than approximately 40.0 × 50.0 mm
(1.6 × 2.0 in.). Expose sufficient size or multi-
ple specimens to include all colors in the speci-
men.
44.8 Specimen frames must be made of
stainless steel, aluminum, or suitably coated
steel to avoid contaminating the specimens
with metallic impurities that might catalyze or
inhibit the degradation. When specimens are
fastened with staples, they should be of the
nonferrous type overcoated to avoid contami-
nation of the specimen by corrosion products.
Metal frames must have a dull finish and be
designed to avoid reflectances that could in-
fluence the performance of the material.
Frames shall conform to the curvature of the
specimen rack. The size of the frame is deter-
mined by the type specimens required for indi-
vidual property requirements.
44.9 Available from ASTM International,
100 Barr Harbor Dr., W. Conshohocken PA
19428; tel: +1.610.832.9500; fax: +1.610.832.
9555; web site: https://www.wendangku.net/doc/1118139005.html,.
44.10 An automated electronic grading sys-
tem may be used as long as the system has
been demonstrated to provide results that are
equal to and provide equal or better repeatabil-
ity and reproducibility than an experienced
grader performing visual evaluations.
44.11 Classificati o n Based o n the
AATCC Blue Wool Lightfastness Standards
44.11.1 One Step Exposure—Classify
lightfastness of the material by:
Table II—Classification by AATCC Blue Wool Lightfastness Standards a
Test Specimen Color Change
Less Than
Standard
Equal To But Not
Greater Than
Standard
More Than
Standard
Lightfastness
Class
AATCC Fading
Units (AFU)——L2L1
—L2L3L25
L2—L3L2-3
—L3L4L310
L3—L4L3-4
—L4L5L420
L4—L5L4-5
—L5L6L540
L5—L6L5-6
—L6L7L680
L6—L7L6-7
—L7L8L7160
L7—L8L7-8
—L8L9L8320
L8—L9L8-9
—L9—L9640
a The following are examples for using Table II to assign lightfastness classifications:
The test specimen is exposed simultaneously with standards L4, L5, and L6. After exposure and condition-ing, the color change exhibited by the test specimen is less than that exhibited by the standards L4 and L5 but greater than that exhibited by the standard L6. The test specimen would be assigned a Lightfastness Classification of L5-6, or use the following example.
The test specimen is examined after each exposure increment until it exhibits a color change equal to Step 4 on the Gray Scale for Color Change. If this occurs after 40 AFU and before 80 AFU exposure, the test specimen would be assigned a Lightfastness Classification of L5-6.
(a) comparison of the color change of the test specimen to that of a simultaneously ex-posed series of AATCC Blue Wool Lightfast-ness Standards (see Table II), or
(b) determination of the number of AATCC Fading Units required to produce a color change in the test specimen equal to Step 4 of the Gray Scale for Color Change (see Table I).
44.11.2 Two Step Exposure—Classify lightfastness of the material by:
(a) determination of the number of AATCC Fading Units required to produce color changes in the test specimen equal to both a Step 4 and Step 3 on the Gray Scale for Color Change (see Table I).
44.11.3 Assign both classifications: the Step 3 level appears first, followed by the Step 4 level in parentheses. For example, a L5(4) classification would illustrate a L5 classifica-tion at Step 3 color change and a L4 classifica-tion at Step 4 color change. When only one classification number is assigned, it shall rep-resent the number of AATCC Fading Units to produce a Step 4 color change.
44.12 Classificatio n abo ve L7 AATCC Blue Wool Lightfastness Standard
44.12.1Using Table III, classify lightfast-ness above the L7 AATCC Blue Wool Light-fastness Standard according to the total number of consecutive L7 standards exposed to Step 4 on the Gray Scale for Color Change during the exposure cycle that is required to produce a Step 4 color change on the test spec-imen, and Table III.
Appendix A
Xenon-Arc Lamp Fading Apparatus A. Xenon-Arc Lamp Fading Apparatus
A1 Different types of xenon-arc test apparatus may be utilized provided that the test apparatus is capable of automati-cally controlling irradiance level, humid-ity level, chamber air temperature, and Black Panel or Black Standard Ther-mometer temperature.
A2 The design of the test chamber may
vary, but it should be constructed from
corrosion resistant material.
A3 Xenon-Arc Light Source. The xe-
non-arc test apparatus utilizes a long-arc
quartz-jacketed xenon-arc lamp as the
source of irradiance which emits radia-
tion from below 270 nm in the ultraviolet
through the visible spectrum and into the
infrared.
While all of the xenon-arc lamps are of
the same general type, different size
lamps operated in different wattage
ranges are employed in several sizes and
types of apparatus. In each of the various
models, the size and dimension of the
specimen rack varies according to the
lamp size and the wattage at which it is
operated to provide an irradiance at the
face of the specimen of 1.10 ± 0.03 W/
(m2nm) measured at 420 nm or equiva-
lent when exposed in standard holders.
A3.1 Aging of the xenon burners or fil-
ters can result in changes in lamp spec-
trum. Changes in lamp spectrum may
also be caused by accumulation of dirt or
other residue in or on the burner envelope.
A3.2 Filter—In order for xenon-arcs to
simulate terrestrial daylight, filters must
be used to remove short wavelength UV
radiation. In addition, filters to remove
infrared radiation may be used to prevent
unrealistic heating of test specimens that
can cause thermal degradation not experi-
enced during outdoor exposures. Filters
to reduce irradiance at wavelengths
shorter than 310 nm must be used to sim-
ulate daylight filtered through window
glass.
The instrument manufacturers’ recom-
mendations should be used to provide the
appropriate spectrum (see A3.4 below).
Replace filters when chipped, cracked, or
when discoloration or milkiness devel-
ops. Discard xenon lamp tubes and filters
at the manufacturer’s recommended time
intervals or sooner, or when 20 AATCC
Fading Units can no longer be attained in
20 ± 2 continuous light-on operating
(clock) hours.
A3.3 Spectral Irradiance of Filtered
Xenon-Arc—Fig. A1 shows the desired
relative spectral power distribution for
filtered xenon-arcs comply with these
limits. The acceptable limits for variation
of the relative spectral power distribution
shown in Fig. A1 are on file at the
AATCC Technical Center.
A3.4 Follow the device manufacturer’s
instructions for recommended maintenance.
Table III—Classification by AATCC Blue Wool Lightfastness Standards Above L7
Number of L7 Standards Exposed
Lightfastness
Class Equivalent AATCC Fading Unit
(AFU)
Less Than Equal To But Not
Greater Than More Than
—2—L8320
3—2L8-9—
—3—L8-9480
4—3L8-9—
—4—L9640
5—4L9-10—
—5—L9-10800
6—5L9-10—
—6—L9-10960
7—6L9-10—
—7—L9-101120
8—7L9-10—
—8—L101280
etc.a etc.a etc.a etc.a
a A classification increase of 1 represents the interval when the equivalent AATCC Fading Units are doubled
from the previous whole number classification. Any test specimen for which the number of L7 Standards
fall between two whole number classifications is assigned both the lower and higher classification defining
that interval.
Fig. A1—Filtered Xenon Lamp Spectral Power
Distribution Controlled at 1.1 W/(m2nm) at 420 nm
Table IV—Reporting Form
Operator’s Name___________________________________________________________________________________Date__________________________ Sample Identification_________________________________________________________________________________________________________________ Material Exposed:Face___________________________________Back___________________________________
Colorfastness to Light Rating___________________________________Lightfastness Classification___________________________________ Acceptance Compared to Reference Sample (Yes/No)____________________________________
Test Specimen Compared To: Masked Portion____________________________________
Unmasked Portion_________________________________Unexposed Original_________________________________
Colorfastness to Light Rating determined by:
Gray Scale for Color Change__________________________________________
Instrumentally, Name Type__________________________________________________________________________________________________________ Classification Method________________________________________________________________________________________________________________ Reference Standard_________________________________________________________________________________________________________________ Temperature Controlled By: Ambient (Dry Bulb)_____________________________________°C
Black Panel_________________________________°C Black Standard________________________________°C
Exposure Controlled By: AATCC Blue Wool Lightfastness Standards_______________________________________
Radiant Energy_________________________________Other______________________________
Total Radiant Energy__________________________________
Type of Test Apparatus______________________________________________________________________________Model No.______________________ Serial No._______________________________Manufacturer’s Name______________________________________________________________________ Specimen Rack:Inclined ___________________2-Tier ____________________3-Tier ____________________Horizontal_______________________ Type of Water Supply________________________________________________________________________________________________________________ Option Employed____________________________________Elapsed Exposure Time_____________________________
Mounting Procedure:Backed_______________________________Unbacked_________________________________
Sample Rotation Schedule________________________________% Relative Humidity__________________________________
For Daylight Behind Glass, report the following:
Geographical Location_______________________________________________________________________________________________________________ Exposure Dates:From_________________________________To______________________________
Exposure Latitude_________________________________Exposure Angle_______________________________
Exposed Behind Window Glass:Yes/No____________________________________If Yes, Specify Type_________________________________
Daily Ambient Temperature:Minimum __________°C Maximum __________°C Avg. __________°C
Daily Black Panel Temperature:Minimum __________°C Maximum __________°C Avg. __________°C
Test Environment Temperature:Minimum __________°C Maximum __________°C Avg. __________°C
Daily% Relative Humidity:Minimum __________Maximum __________Avg. __________
Hours of Wetness:Rain________________________________Rain and Dew_____________________
Appendix B
Flow Chart for AATCC Test Method 16.3, Xenon-Arc