Colorfastness to Light

AATCC Test Method 16-2004

Developed in 1964 by AATCC Commit- Precision and Bias...... 29-30 tion of the maximum temperature a spec- tee RA50; revised 1971, 1974, 1978, References...... 31 imen may attain during exposure to natu- 1981, 1982, 1990 (Supersedes AATCC Notes ...... 32 ral or artificial light. Any deviation from Test Methods 16-1987, 16A-1988, 16C- Appendix...... A-C the geometry of the device described in 1988, 16D-1988, 16E-1987, 16F-1988 32.2 may have an influence on the mea- and 16G-1985), 1993, 2003, 2004; re- sured temperature. The temperature mea- affirmed 1977, 1998; editorially revised 2. Principle sured by the black standard thermometer 1983, 1984, 1986, 1995, 1996. Tech- 2.1 Samples of the textile material to will not be the same as that measured by nically equivalent: Option 6-ISO 105- be tested and the agreed upon comparison the black-panel thermometer; therefore, B01; Related to Option 3-ISO 105-B02. standard(s) are exposed simultaneously they cannot be used interchangeably. to a light source under specified condi- 3.5 broad bandpass radiometer, n.— tions. The colorfastness to light of the a relative term applied to radiometers that specimen is evaluated by comparison of have a bandpass width of more than 1. Purpose and Scope the color change of the exposed portion 20 nm at 50% of maximum transmittance to the masked control portion of the test and can be used to measure irradiance at 1.1 This test method provides the gen- specimen or unexposed original material wavelengths such as 300-400 nm or 300- eral principles and procedures which are using the AATCC Gray Scale for Color 800 nm. currently in use for determining the col- Change, or by instrumental color mea- 3.6 color change, n.—as used in colorfastness to light of textile materials. surement. Lightfastness classification is orfastness testing, a change in color of The test options described are applicable accomplished by evaluation versus a si- any kind whether a change in lightness, to textile materials of all kinds and for multaneously exposed series of AATCC hue or chroma or any combination of colorants, finishes and treatments applied Blue Wool Lightfastness Standards. these, discernible by comparing the test to textile materials. specimen with a corresponding untested Test options included are: specimen. 1—Enclosed Carbon-Arc Lamp, Contin- 3. Terminology 3.7 colorfastness, n.—the resistance of uous Light 3.1 AATCC Blue Wool Lightfastness a material to change in any of its color 2—Enclosed Carbon-Arc Lamp, Alter- Standard, n.—one of a group of dyed characteristics, to transfer of its colo- nate Light and Dark wool fabrics distributed by AATCC for rant(s) to adjacent materials, or both as a 3—Xenon-Arc Lamp, Continuous Light, use in determining the amount of light result of exposure of the material to any Black Panel Option exposure of specimens during lightfast- environment that might be encountered 4—Xenon-Arc Lamp, Alternate Light ness testing (see 32.1). during the processing, testing, storage or and Dark 3.2 AATCC Fading Unit (AFU), n.— use of the material. 5—Xenon-Arc Lamp, Continuous Light, a specific amount of exposure made un- 3.8 colorfastness to light, n.—the re- Black Standard Option der the conditions specified in various sistance of a material to a change in its 6—Daylight Behind Glass test methods where one AFU is one- color characteristics as a result of expo- 1.2 The use of these test options does twentieth (1/20) of the light-on exposure sure of the material to sunlight or an arti- not imply, expressly or otherwise, an ac- required to produce a color change equal ficial light source. celerated test for a specific application. to Step 4 on the Gray Scale for Color 3.9 infrared radiation, n.—radiant The relationship between any lightfast- Change or 1.7 ± 0.3 CIELAB units of energy for which the wavelengths of the ness test and the actual exposure in use color difference on AATCC Blue Wool monochromatic components are greater must be determined and agreed upon by Lightfastness Standard L4. than those for visible radiation and less the contractual parties. 3.3 black-panel thermometer, n.—a than about 1 mm. 1.3 This test method contains the fol- temperature measuring device, the sens- NOTE: The limits of the spectral range lowing sections that assist in the use and ing unit of which is coated with black of infrared radiation are not well defined implementation of the various options paint designed to absorb most of the radi- and may vary according to the user. Com- for determining lightfastness of textile ant energy encountered in lightfastness mittee E-2.1.2 of the CIE distinguishes in materials. testing (see 32.2). the spectral range between 780 nm and Section 3.3.1 This device provides an estima- 1mm: Terminology...... 3 tion of the maximum temperature a spec- IR-A 780-1400 nm Safety Precautions ...... 4 imen may attain during exposure to natu- IR-B 1.4-3.0 µm Uses and Limitations ...... 5 ral or artificial light. Any deviation from IR-C 3 µm to 1 mm Apparatus and Materials...... 6 the geometry of this device described in 3.10 irradiance, n.—radiant power per Comparison Standards...... 7 32.2 may have an influence on the mea- unit area incident on a receiver, typically Test Specimen Preparation ...... 8 sured temperature. reported in watts per square meter, W/ Machine Operating Conditions ... 9 3.4 black standard thermometer, (m2nm). Calibration and Verification ...... 10-12 n.—a temperature measuring device, the 3.11 “L” designation, n.—the se- AATCC Fading Unit sensing unit of which is coated with black quence number given each AATCC Blue Measurement...... 13-14 material designed to absorb most of the Wool Lightfastness Standard according to Machine Exposure Procedures .... 15-18 radiant energy encountered in lightfast- the number of AATCC Fading Units re- Daylight Exposure Procedures .... 19-22 ness testing and is thermally insulated by quired to produce a color change equal to Evaluation of Results...... 23-27 means of a plastic plate (see 32.2). Step 4 on the AATCC Gray Scale for Report ...... 28 3.4.1 This device provides an estima- Color Change.

AATCC Technical Manual/2006 TM 16-2004 23

Copyright © 2005 American Association of Textile Chemists and Colorists NOTE: See Table II for the numerical UV-A 315-400 nm equally by the same light source and en- relationship between “L” designations of UV-B 280-315 nm vironment. Results obtained by the use of the standards and their colorfastness to UV-C 100-280 nm any one test option may not be represen- light in AFUs. The colorfastness to light 3.21 visible radiation, n.—any radiant tative of those of any other test option or of a fabric specimen can be determined energy capable of causing a visual any end-use application unless a mathe- by comparing its color change after light sensation. matical correlation for a given material exposure with that of the most similar NOTE The limits of the spectral range and/or a given application has been estab- AATCC Blue Wool Lightfastness Stan- of visible radiation are not well defined lished. Enclosed Carbon-Arc, Xenon-Arc dard as shown in Table III. and may vary according to the user. The and Daylight have been extensively used 3.12 langley, n.—a unit of total solar lower limit is generally taken between in the trade for acceptance testing of tex- radiation equivalent to one gram calorie 380 and 400 nm and the upper limit tile materials. There may be a distinct dif- per square centimeter of irradiated sur- between 760 and 780 nm (1 nanometer, ference in spectral power distribution, air face. 1nm = 10–9 m). temperature and humidity sensor loca- NOTE: The internationally recom- 3.22 xenon reference fabric, n.—a tions, and test chamber size between test mended units are: Joule (J) for quantity of dyed polyester fabric used for verifying equipment supplied by different manu- radiant energy, watt (W) for quantity of xenon-arc equipment test chamber tem- facturers that can result in differences in radiant power, and meter squared (m2) for perature conditions during a lightfastness reported test results. Consequently, data area. The following factors are to be test cycle (see 32.3, 32.4 and 32.6). obtained from equipment supplied by the used: 1 langley = 1 cal/cm2; 1 cal/cm2 = 3.23 For definitions of other terms rel- different manufacturers, different test 4.184 J/cm2 or 41840 J/m2. ative to lightfastness used in this test chamber size, or different light source 3.13 lightfastness, n.—the property of method, refer to the Glossary of AATCC and filter combinations cannot be used a material, usually an assigned number, Standard Terminology. interchangeably, unless a mathematical depicting a ranked change in its color correlation has been established. No cor- characteristics as a result of exposure of relations among differently constructed 4. Safety Precautions the material to sunlight or an artificial test apparatus are known to AATCC light source. NOTE: These safety precautions are Committee RA50. 3.14 narrow bandpass radiometer, for information purposes only. The pre- 5.2 Results from Xenon-Arc, for all n.—a relative term applied to radiometers cautions are ancillary to the testing proce- materials should be in good agreement that have a bandpass width of 20 nm or dures and are not intended to be all inclu- with the results obtained in Daylight Be- less at 50% of maximum transmittance sive. It is the user’s responsibility to use hind Glass (see Table II). Since the spec- and can be used to measure irradiance safe and proper techniques in handling tral distribution of Xenon-Arc, Alternate at wavelengths such as 340 or 420, ± 0.5 materials in this test method. Manufac- Light and Dark, equipped with the speci- nm. turers MUST be consulted on specific de- fied filter glass is very close to that of av- 3.15 photochromism, n.—a qualita- tails such as material safety data sheets erage or typical daylight behind window tive designation for a reversible change in and other manufacturer’s recommenda- glass, it is expected that results should be color of any kind (whether a change in tions. All OSHA standards and rules in good agreement with the results ob- hue or chroma) which is immediately must also be consulted and followed. tained in Daylight, Daylight Behind noticeable upon termination of light ex- 4.1 Do not operate the test equipment Glass. The two carbon-arc options, Con- posures when the exposed area of a until the manufacturer’s instructions have tinuous and Alternating Light and Dark, specimen is compared to the unexposed been read and understood. It is the opera- under the conditions specified, will pro- area. tor’s responsibility to conform to the duce results which correlate with those NOTE: The reversion of the color manufacturer’s directions for safe opera- obtained in the Daylight Behind Glass change or instability of the hue or chroma tion. Method unless the material being tested upon standing in the dark distinguishes 4.2 The test equipment contains high is adversely affected by the differences in photochromism from fading. intensity light sources. Do not look di- spectral characteristics of Enclosed Car- 3.16 pyranometer, n.—a radiometer rectly at the light source. The door to the bon-Arc and natural light. used to measure the global solar irradi- test chamber must be kept closed when 5.3 When using this test method, the ance or, if inclined, hemispherical solar the equipment is in operation. test method option selected should incor- irradiance. 4.3 Before servicing light sources, al- porate light, humidity, and heat effects 3.17 radiant power, n.—energy per low 30 min for cool-down after lamp op- based upon historical data and experi- unit time emitted, transferred or received eration is terminated. ence. The test method option selected as radiation. 4.4 When servicing the test equipment, should also reflect expected end-use con- 3.18 radiometer, n.—an instrument shut off both the off switch and the ditions associated with the material to be used to measure radiant energy. main power disconnect switch. When tested. 3.19 total irradiance, n.—radiant equipped, ensure that the main power in- 5.4 When using this test method, use a power integrated over all wavelengths at dicator light on the machine goes out. standard of comparison which has a a point in time expressed in watts per 4.5 Daylight exposure of the skin and known change in lightfastness after a spe- square meter (W/m2). eyes for prolonged periods may be cific exposure for comparison to the ma- 3.20 ultraviolet radiation, n.—radiant hazardous and therefore caution should terial to be tested. AATCC Blue Wool energy for which the wavelengths of the be employed to protect these areas. Do Lightfastness Standards have been used monochromatic components are smaller not look directly at the sun under any extensively for this purpose. than those for visible radiation and more circumstances. than about 100 nm. 4.6 Good laboratory practices should 6. Apparatus and Materials NOTE: The limits of the spectral range be followed. Wear safety glasses in all of ultraviolet radiation are not well de- laboratory areas. 6.1 AATCC Blue Wool Lightfastness fined and may vary according to the user. Standards L2 through L9 (see 32.1 and Committee E.2.1.2 of the CIE distin- 5. Uses and Limitation 32.5). guishes in the spectral range between 400 6.2 Xenon Reference Fabric (see 32.3, and 100 nm: 5.1 Not all materials are affected 32.4, 32.5 and 32.6).

24 TM 16-2004 AATCC Technical Manual/2006

Component Option 1 Option 2 Option 3 Option 4 Option 5 Light Source Enclosed Enclosed bXenonb, c bXenon b cXenon b, c, d Carbon a Carbon a Continuous Light Alternate Light/Dark Continuous Light Alternate Light/Dark Continuous Light Black Panel Temperature, Light Cycle 63 ± 3°C 63 ± 3°C 63 ± 1°C — — (145 ± 6°F) (145 ± 6°F) (145 ± 2°F) — — Black Standard Temperature, Light Cycle — — — 70 ± 1°C 60 ± 3°C — — — (158 ± 2°F) (140 ± 8°F) Chamber Air Temperature, Light Cycle 43 ± 2°C 43 ± 2°C 43 ± 2°C 43 ± 2°C 32 ± 5°C (110 ± 4°F) (110 ± 4°F) (110 ± 4°F) (110 ± 4°F) (90 ± 9°F) Dark Cycle — 43 ± 2°C — 43 ± 2°C — — (110 ± 4°F) — (110 ± 4°F) — Relative Humidity, % Light Cycle 30 ± 5 35 ± 5 30 ± 5 35 ± 5 30 ± 5 Dark Cycle — 90 ± 5 — 90 ± 5 — Light Cycle, Hours Light–On Continuous 3.8 Continuous 3.8 Continuous Light–Off — 1.0 — 1.0 — Filter Type Borosilicate Borosilicate see A.3.3 see A.3.3 see A.3.3 Irradiance W/m2/nm (at 420 nm) Not controlled Not controlled 1.10 ± 0.03 1.10 ± 0.03 1.25 ± 0.2 Irradiance W/m2 (300-400 nm) Not controlled Not controlled 48 ± 1 48 ± 1 65 ± 1 Water Requirements (Input) Type demineralized, distilled or reverse osmosis Solids–ppm less than 17 ppm, preferably less than 8 pH 7 ± 1 Temperature Ambient 16 ± 5°C (61 ± 9°F) a See Appendix C. b See Appendix A. b Be sure that the temperature chosen is appropriate for the type of Black Thermometer to be used. c Options 3 and 5 have different temperature set-points specified because of the differences in the thermal sensing elements between the Black Panel Thermometer and the Black Standard Thermometer. d Option 5 should be used at the recommendation of the equipment manufacturer.

6.3 L4 AATCC Blue Wool Standard of and some European test procedures. fastness Standard by one test option may Fade for 20 AATCC Fading Units (AFU) Temperatures as measured by the two dif- not agree with that of other test options. (see 32.5). ferent devices generally will not agree at 7.2 The reference standard can be any 6.4 L2 AATCC Blue Wool (alternate) the same test condition. The term Black suitable textile material where a history Standard of Fade for 20 AATCC Fading Thermometer, as used in this method, re- of the rate of color change is known. Ref- Units (AFU) (see 11.2, 32.5). fers to both the Black Panel and Black erence standards for comparison must be 6.5 Xenon Reference Fabric Standard Standard Thermometers. determined and agreed upon by the con- of Fade (see 32.5). 6.11 Spectrophotometer or Colorimeter tractual parties. Standards must be ex- 6.6 AATCC Gray Scale for Color (see 31.2). posed simultaneously with the test speci- Change (see 32.5). 6.12 Xenon-Arc Lamp Fading Appara- men. The use of the standard assists in 6.7 Card stock: 163 g/m2 (90 lb) one tus optionally equipped with light moni- determining time-to-time equipment and ply, White Bristol Index (see 32.7). tors and control systems (see 32.9 and test procedure variations. If test results of 6.8 Test masks made of material ap- Appendix A). the exposed standards differ by more than proaching zero light transmittance, and 6.13 Daylight Exposure Cabinet (see 10% from the known standard data, thor- suitable for multiple exposure levels, 32.10 and Appendix B). oughly review the test equipment operat- such as 10, 20, 40, etc. AFU (see 32.8). 6.14 Enclosed Carbon-Arc Lamp Fad- ing conditions, and correct any malfunc- 6.9 Black-Panel Thermometer (see 3.3, ing Apparatus (see 32.9 and Appendix C). tions or defective parts. Then, repeat the 32.2 and 32.9). test. 6.10 Black Standard Thermometer (see 7. Comparison Standards 3.4, 32.2 and 32.9). 8. Test Specimen Preparation NOTE: The Black-Panel Thermometer 7.1 AATCC Blue Wool Lightfastness should not be confused with the Black Standards, as defined in Method 16, are 8.1 Number of Specimens—For accep- Standard Thermometer which is used in preferred for all options. However, the rate tance testing, use at least three replicate Xenon-Arc, Continuous Light, Option 5, of fade of any AATCC Blue Wool Light- specimens of both the material to be

AATCC Technical Manual/2006 TM 16-2004 25

Copyright © 2005 American Association of Textile Chemists and Colorists tested and the standard for comparison to Machine Operating Conditions 10. Calibration, Verification and AATCC ensure accuracy unless otherwise agreed Fading Unit Measurement upon between the purchaser and the 9. Preparation of Test Apparatus supplier. 10.1 Instrument Calibration—To ensure standardization and accuracy, the in- NOTE: It is recognized that in practice 9.1 Prior to running the test procedure, struments associated with the exposure one test and one control specimen are verify machine operation by using the apparatus (that is, light monitor control used for test purposes. While such a following test protocol. To enhance the system, Black Thermometers, chamber procedure cannot be accepted in cases of repeatability of test results, install test ap- air sensor, humidity control system, UV dispute, it may be sufficient in routine paratus in a room where temperature and sensors and radiometers) require periodic testing. relative humidity are controlled in accor- calibration. Whenever possible, calibra- dance with the manufacturer’s recom- tion should be traceable to national or 8.2 Specimen Cutting and Mounting— mendations. Identify each sample using a label resis- international standards. Calibration sched- tant to the environment encountered dur- 9.2 Check to see that the machine has ule and procedure should be in according the test. Mount in frames such that been calibrated and maintained within the ance with manufacturer’s instructions. the surface of the test specimen and the manufacturer’s recommended calibra- 10.1.1 The accuracy of machine operation schedule interval. reference specimen are the same distance tion must be verified by exposure of an from the light source. Use covers that 9.3 Turn off all rack and specimen applicable AATCC Blue Wool Lightfast- avoid specimen surface compression, spray units, if applicable. ness Standard and assessment of the Standard after every 80-100 AATCC particularly when testing pile fabrics. The 9.4 Set machine operating conditions according to Table I and the specified op- Fading Units. Always expose reference test specimen and the reference standards standards near the center position of the shall be of equal size and shape. Cut and tion. Be sure that the temperature chosen is appropriate for the type of Black Ther- specimen rack adjacent to the black-panel prepare test specimens for exposure as temperature sensing unit. follows: mometer to be used (see 32.2). Fill the specimen rack with framed white card 8.2.1 Specimen Backing—For all op- stock and the required black thermometer 11. Calibration by AATCC Blue Wool tions, mount the specimens and standards unit. The white card stock is used to sim- Lightfastness Standards on white card stock. When mounted test ulate air flow in the test chamber during 11.1 Carbon-Arc Options 1 and 2; specimens are masked, use test masks ap- the test exposure and should not include proaching zero light transmittance. For Xenon-Arc Options 3 and 4, expose the the actual test specimens. Support the L4 AATCC Blue Wool Lightfastness Option 6, put the mounted, or mounted black thermometer unit in the specimen and masked, test specimens in frames Standard at the specified temperature, hu- drum or rack in the same manner as the midity and selected option for 20 ± 2 with backing as directed in an applicable test specimen frames. Operate and con- specification: such as open-backed, solid continuous light-on operating hours (see trol the test apparatus as specified in Ta- Table II for the corresponding AATCC metal, or solid backing (see 32.4, 32.7 ble I and further defined by the manufac- and 32.8). Fading Units for xenon lamp options). turer. Operate the test apparatus in this After exposure, assess the exposed stan- 8.2.2 Fabric—Cut swatches of fabric mode and adjust the instrumentation to dard specimen, either visually or instru- with the long direction parallel to the ma- provide the required black panel or black mentally. Increase or decrease the watt- chine (warp) direction, at least 70.0 × standard temperature, chamber air tem- age of the lamps, the time of exposure, of 120.0 mm (2.75 × 4.7 in.) with the ex- perature and relative humidity. When ex- both, and expose additional standard posed area measuring not less than 30.0 × terior indicators are not available, read specimens until the change in color of the 30.0 mm (1.2 × 1.2 in.). Secure the the black thermometer unit through the exposed standard meets one of the fol- backed specimens in the frames supplied window in the test chamber door. lowing criteria. with the test apparatus. Ensure that front 9.5 Calibrate using AATCC Blue Wool and back covers of the holders make Lightfastness Standards following the good contact with the specimens and give guidelines in 11.1-11.2.2. If the fade of a sharp line of demarcation between the the L2 or L4 standards do not meet these Table II—AATCC Fading Unit and exposed and unexposed areas without requirements follow the instrument man- Light Exposure Equivalents for compressing the specimen unnecessarily ufacturer’s instructions for calibration AATCC Blue Wool Lightfastness and repeat the 20 AFU exposure with (see 32.11 and 32.12). When required to Standards (see 32.18)a prevent raveling, the samples may be fresh L2 or L4 standards. If the fade does edged by sewing, pinking or fusing. meet the requirements described in Sec- AATCC tion 11 remove the white card stock from Blue Wool AATCC Xenon Only Xenon Only 8.2.3 Yarns—Wind or fasten yarns on the specimen rack and proceed. Lightfastness Fading kJ/(m2 nm) kJ/(m2 nm) frames of white card stock to a length of 9.6 For additional information to pre- Standard Units @ 420 nm 300-400 nm approximately 150.0 mm (6.0 in.). Only pare and operate the test apparatus refer that portion of the yarns directly facing L2 5 21 864 to the manufacturer’s instructions and the L3 10 43 1728 the radiant energy is evaluated for color following: L4 20 85b 3456 change. Wind the yarn on the frame 9.6.1 For Both Enclosed Carbon-Arc L5 40 170 6912 closely packed to at least 25.0 mm (1.0 b b Options, use Test Standard ASTM G 151 L6 80 340 13824 in.) width. The control sample must con- L7 160 680 27648 and G 153 (see 31.3 and 31.4). tain the same number of strands as the L8 320 1360 55296 sample subjected to exposure. After the 9.6.2 For Daylight Behind Glass, use L9 640 2720 1105920 exposure has been completed, bind to- Test Standard ASTM G 24 (see 31.5). gether those yarns facing the light source 9.6.3 For all Xenon Options, use Test a For color change of 1.7 ± 0.3 CIELAB units or using 20.0 mm (0.75 in.) masking or Standard ASTM G 151 and G 155 (see Step 4 on the AATCC Gray Scale for Color 31.3 and 31.6). Change. other suitable tape to keep the yarns b Verified by experiment using Daylight Behind closely packed on the exposure frame for 9.6.4 For Options as applicable, refer Glass and Xenon-Arc, Continuous Light. All evaluation (see 32.12). to ISO 105, Part B (see 31.7). other values are calculated (see 32.18).

26 TM 16-2004 AATCC Technical Manual/2006

Copyright © 2005 American Association of Textile Chemists and Colorists Table III—Classification by AATCC Blue Wool Lightfastness Standardsa ment—If the exposed standard specimen Test Specimen Color Change equals 20 ± 1.7 CIELAB units of color change in 20 ± 2 continuous light-on op- Equal To But Not erating hours, the test machine is provid- Less Than Greater Than More Than Lightfastness AATCC Fading ing the correct temperature. Standard Standard Standard Class Units (AFU) 12.2 If the exposed Xenon Reference — — L2 L1 Fabric differs visually, or instrumentally, —L2L3L25from that specified in 12.1.1 or 12.1.2, as L2 — L3 L2-3 applicable, after 20 ± 2 continuous light- —L3L4L310on operating hours, it is an indication that L3 — L4 L3-4 temperature sensing units within the test —L4L5L420 L4 — L5 L4-5 chamber are not calibrated or responding —L5L6L540correctly, or that the test equipment re- L5 — L6 L5-6 quires maintenance. Verify the accuracy —L6L7L680of the temperature sensors and that all L6 — L7 L6-7 machine functions are operating correctly —L7L8L7160according to the manufacturer’s instruc- L7 — L8 L7-8 tions. Replace temperature sensors if they —L8L9L8320are defective. L8 — L9 L8-9 — L9 — L9 640 13. AATCC Fading Unit Measurement by AATCC Blue Wool Lightfastness a The following are examples for using Table III to assign lightfastness classifications: Standards The test specimen is exposed simultaneously with standards L4, L5, and L6. After exposure and conditioning, the color change exhibited by the test specimen is less than that exhibited by the standards L4 and L5 13.1 The use of AATCC Blue Wool but greater than that exhibited by the standard L6. The test specimen would be assigned a Lightfastness Lightfastness Standards and AATCC Classification of L5-6, or use the following example. Fading Units provides a common expo- The test specimen is examined after each exposure increment until it exhibits a color change equal to Step sure standard across the various exposure 4 on the AATCC Gray Scale for Color Change. If this occurs after 40 AFU and before 80 AFU exposure, the methods: daylight, carbon-arc lamp and test specimen would be assigned a Lightfastness Classification of L5-6. xenon-arc lamp. The terms clock hours and machine hours are not valid reporting methods. 13.2 Table II illustrates the number of AATCC Fading Units to produce a color 11.1.1 Visual Comparison—equals the Lightfastness Standard L2, equals 7.24 ± change equal to Step 4 on the Gray Scale change in color exhibited by the L4 Stan- 0.70 CIELAB units of color change as for Color Change on each of the AATCC dard of Fade applicable to the Lot desig- determined by AATCC Evaluation Pro- Blue Wool Lightfastness Standards. nation used. cedure 6. Other Lot designations of 13.3 For instrumental color measure- 11.1.2 Instrumental Color Measure- AATCC Blue Wool Lightfastness Stan- ment, the colorimetric data are calculated ment—for Lot 5, AATCC Blue Wool dard L2 equal the CIELAB unit of color using CIE 1964 10° observer data for Il- Lightfastness Standard, equals 1.7 ± 0.3 change specified on the calibration certif- luminant D65. Express the color differ- CIELAB units of color change as deter- icate supplied with the standard as deter- ence in CIELAB units as directed in mined by AATCC Evaluation Procedure mined by AATCC Evaluation Procedure AATCC Evaluation Procedure 6. NOTE: 6. Other Lot designations of AATCC 6. For Xenon-Arc, Alternating Light and Blue Wool Lightfastness Standard L4 NOTE: The Xenon Reference fabric is Dark, Option 4, although calibration is equals the CIELAB units of color change discontinued for calibration since it is conducted using continuous light-on op- specified on the calibration certificate temperature sensitive. It is more appro- erating hours, it may take more or less supplied with the standard as determined priately used to monitor test chamber operating hours during the actual test by AATCC Evaluation Procedure 6. temperature conformance (see Sections cycle due to the inclusion of the dark 11.2 Alternate for Carbon-Arc Options 12, 32.3, 32.4 and 32.6). periods. 1 and 2; Xenon-Arc Options 3 and 4, the L2 AATCC Blue Wool Lightfastness 12. Verification of Test Chamber Standard may be exposed at the specified 14. AATCC Fading Unit Measurement Temperature by Xenon Reference based on Spectral Irradiation, temperature, humidity and selected op- Fabric, Xenon-Arc Options tion for 20 ± 2 continuous light-on oper- Xenon-Arc, Options 3 and 4 only ating hours. After exposure, assess the 12.1 Expose the Xenon Reference 14.1 For Options 3 and 4, 20 AATCC exposed standard specimen, either instru- Fabric for 20 ± 2 continuous light-on Fading Units are produced by an expo- mentally or compare to a L2 Standard of operating hours at the specified tempera- sure interval of 85 kJ/(m2nm) measured Fade. When required, increase or de- ture, humidity and selected option. As- at 420 nm when xenon-arc machines are crease the wattage of the lamps, or the sess the exposed standard specimen, ei- operated at the conditions specified in time of exposure, or both, and expose ad- ther visually or instrumentally, by one of this test method (see Table II). ditional standard specimens until the the following: change in color of the exposed standard 12.1.1 Visual Comparison—If the Machine Exposure Procedures, meets one of the following criteria. color change of the exposed standard Options 1-5 11.2.1 Visual Comparison—equals the specimen equals the Xenon Reference change in color exhibited by the L2 Stan- Fabric Standard of Fade in 20 ± 2 contin- 15. Machine Exposure, General Conditions dard of Fade applicable to the Lot desig- uous light-on operating hours the test nation used (see 32.5). equipment is maintaining the correct tem- 15.1 Specimen Mounting. Mount the 11.2.2 Instrumental Color Measure- perature. framed test material on the specimen ment—for Lot 8, AATCC Blue Wool 12.1.2 Instrumental Color Measure- rack. Make sure that all materials are ade-

AATCC Technical Manual/2006 TM 16-2004 27

Copyright © 2005 American Association of Textile Chemists and Colorists quately supported, both top and bottom, the required end point in terms of test specimen(s) to be exposed as directed in proper alignment. Any displacement of AATCC Fading Units, kilojoules per in 19.1 and expose simultaneously to the the material toward or away from the square meter of irradiance or reference same test conditions behind glass as di- source, even by a small distance, may specimen performance (that is, the refer- rected in 19.2. Monitor the effect of light lead to variation in fading between speci- ence specimen shows a color change by frequently removing the standard(s) mens (see 8.2). The specimen rack must equal to Step 4 on the Gray Scale of from the test frame and evaluating the be filled; card stock is used when the Color Change). color change. Continue the exposure until number of specimens being tested is in- the standard exhibits a difference in color sufficient to fill the specimen rack. When 18. Machine Exposure for Lightfastness between the exposed and masked portion alternate light and dark cycles are re- Classification as described in Section 24. When the test quired, begin exposure at the start of the of the specimens is to be terminated after light cycle. 18.1 One-Step Method—Expose test exposure to a specified number of 15.2 In the case of woven, knitted and specimen(s) simultaneously with a series AATCC Fading Units, choose the appro- nonwoven fabrics, unless otherwise spec- of AATCC Blue Wool Lightfastness priate standard to achieve the end point. ified, ensure that the side normally used Standards or determine the number of The standards may be used as a set, L2 as the face is directly exposed to the radi- AATCC Fading Units required to pro- through L9, or in replicate sets exposed ant source. duce a color change in the test specimen consecutively to total a given end point; 15.3 Operate the test apparatus on a equal to Step 4 on the Gray Scale for that is, singularly expose two L2 stan- daily basis until the selected exposure has Color Change (see 32.22). dards to reach 10 fading units, or expose been completed. Avoid unnecessary de- 18.2 Two-Step Method—Proceed as one L3 standard to reach 10 fading units. lays when interrupting the exposure pe- directed in 18.1, except double the expo- 20.1.1 Remove the samples from expo- riod to change filters, carbons or lamps, sure area of the test specimens. After the sure when the desire AATCC Fading as such delays may contribute to varia- specimen has been exposed to a color Units have been achieved and evaluate as tions in results or lead to errors. When change equal to Step 4 on the Gray Scale specified in Evaluation of Results. For available, monitor exposure test chamber for Color Change, remove the specimens multiple step exposure, that is, 5 fading conditions with suitable recorders. If nec- from the test chamber and mask (cover) units and 20 fading units, a single sample essary, readjust the controls to maintain one-half of the exposed area and continue may be exposed and portions covered the specified test conditions. Verify cali- the exposure until the test specimen ex- (masked) at intervals measured by the bration of the test apparatus during the hibits a color change equal to Step 3 on standard. The result will be a sample hav- test cycle (see Sections 10, 11, 12 and the Gray Scale for Color Change (see ing an original masked, unexposed sec- 13). 32.22). tion and various sections which have Daylight Behind Glass been exposed and subsequently masked. 16. Machine Exposure to a Specified Each section of the specimen, represent- Amount of Radiant Energy, Options 1-5 19. Daylight Behind Glass, General ing a stated exposure interval, can be Conditions, Option 6 evaluated versus masked control or an 16.1 One-Step Method—Expose the unexposed original portion of the sample. test specimens and applicable standards 19.1 Mount the AATCC Blue Wool 20.2 Use of Irradiation Monitors— for 5, 10, 20 or multiples of 20 AATCC Lightfastness Standard(s) and the test spec- Fading Units until the specimen has been Mount reference and test specimen(s) to imen(s) on cardboard with an opaque cover be exposed as directed in 19.1 and expose exposed to the desired amount of radiant (mask) covering one-half of the standard. energy defined in terms of AATCC Fad- them simultaneously to the same test con- 19.2 Expose standards and test speci- ditions behind glass as directed in 19.2. ing Units measured by simultaneous ex- men(s) simultaneously to the same test NOTE: The exposure of the AATCC posure of the appropriate Blue Wool conditions behind glass (see 32.14 and Standard(s). Appendix B). Ensure that the face of the Blue Wool Lightfastness Standards with their known performance can be helpful 16.2 Two-Step Method—Proceed as exposed standard(s) and test specimen(s) in determining whether any unusual con- directed in 16.1, except double the expo- are at least 75.0 mm (3.0 in.) below the sure area of the test specimens. After the inside surface of the plate glass cover and ditions were present during the test dura- tion (see 32.16). specimen has been exposed to the first are positioned at least 150.0 mm (6.0 in.) specified level of radiant energy, remove in from the edges of the glass frame. The 20.2.1 Record any one, or a combina- the specimens from the test chamber and back of the exposure cabinet may be var- tion of global, broad bandpass, or narrow mask (cover) one-half of the exposed ied as follows to achieve the desired ex- bandpass irradiation with a radiometer, area and continue the exposure for an ad- posure conditions: exposed under the same conditions as the ditional 20 or multiples of 20 AATCC specimens (see 32.17). Fading Units until the specimen has been Backing Exposure Condition 20.2.2 Remove the reference and test exposed to the higher desired amount of specimens from exposure when the de- radiant energy. Open Low Temperature sired radiant energy, as measured by the 16.3 In those machines equipped with Expanded Metal Medium Temperature radiometer, has been achieved. For multi- irradiation monitors, the AATCC Fading Solid High Temperature ple step exposure, a single sample may be Units of exposure can be determined and Standard(s) and specimen(s) remain ex- exposed and portions covered (masked) controlled by measuring kJ/(m2nm) at posed 24 h a day and are removed only at intervals of measured radiant exposure 420 nm (see 14.1 and Table II). for inspection. (see 20.1.1). NOTE: The two-step method is pre- 19.3 Monitor temperature and relative ferred for the complete characterization humidity in the vicinity of the test cabi- of the lightfastness of a test specimen. nets (see 32.21). 21. Daylight Exposure Using a Reference Specimen 17. Machine Exposure using a Reference 20. Daylight Behind Glass Exposure to a Specimen, Options 1-5 Specified Amount of Radiant Energy 21.1 Substitute reference specimen(s) for the AATCC Blue Wool Lightfastness 17.1 Expose the test specimen(s) and 20.1 Use of AATCC Blue Wool Light- Standards and proceed as directed in 20.1 reference specimen(s) simultaneously to fastness Standards—Mount reference and and 20.2, as applicable.

28 TM 16-2004 AATCC Technical Manual/2006

Copyright © 2005 American Association of Textile Chemists and Colorists 22. Daylight Exposure for Lightfastness rial as directed in Section 24 in terms of Step 3 level appears first, followed by the Classification the agreed upon reference specimen. Step 4 level in parentheses. For example, 25.2 Assess the lightfastness of the ma- a L5(4) classification would illustrate a 22.1 One-Step Method—Expose test terial as follows: L5 classification at Step 3 color change specimen(s), as detailed in 19.1 and 19.2, and a L4 classification at Step 4 color simultaneously with a series of AATCC 25.2.1 Satisfactory—If the test specimen exhibits a color change equal to or change. When only one classification Blue Wool Lightfastness Standards or de- number is assigned, it shall represent the termine the number of AATCC Fading less than the reference specimen at the exposure level when the reference speci- number of AATCC Fading Units to pro- Units required to produce a color change duce a Step 4 color change. in the test specimen equal to Step 4 on the men shows a color change equal to Step 4 Gray Scale for Color Change (see 32.22). on the AATCC Gray Scale for Color Change. 22.2 Two-Step Method—Proceed as di- 27. Classification above L7 AATCC Blue rected in 22.1, except double the exposure 25.2.2 Unsatisfactory—If the test Wool Lightfastness Standard specimen exhibits a color change greater area of the test specimens. After the speci- 27.1 Using Table IV, classify lightfast- men has been exposed to a color change than the reference specimen at the exposure level when the reference specimen ness above the L7 AATCC Blue Wool equal to Step 4 on the Gray Scale for Lightfastness Standard according to the Color Change, remove the specimens shows a color change equal to Step 4 on the AATCC Gray Scale for Color Change. total number of consecutive L7 standards from the test chamber and mask (cover) exposed to Step 4 on the Gray Scale for one-half of the exposed area and continue Color Change during the exposure cycle the exposure until the test specimen exhib- 26. Classification Based on the AATCC that is required to produce a Step 4 color its a color change equal to Step 3 on the Blue Wool Lightfastness Standards change on the test specimen, and Table IV. Gray Scale for Color Change (see 32.22). 26.1 One Step Exposure—Classify Evaluation of Results lightfastness of the material by: 28. Report (a) comparison of the color change of 28.1 Use Table V to report all applica- 23. Conditioning the test specimen to that of a simultaneously exposed series of AATCC Blue ble information. 23.1 After the test exposure is com- Wool Lightfastness Standards (see Table 28.2 Report any deviation from Test pleted, remove the test specimens and III), or Method 16 or the performance of the ref- comparison standards from exposure. (b) determination of the number of erence standard. Condition in a dark room at standard con- AATCC Fading Units required to pro- 28.3 Report all information in Table V ditions for testing textiles, as directed in duce a color change in the test specimen for the same conditions that the samples ASTM D 1776, Standard Practice for equal to Step 4 of the Gray Scale for and reference materials are exposed. Conditioning and Testing Textiles. [65 ± Color Change (see Table II). Precision and Bias 2% RH and 21 ± 1C (70 ± 2F)] for a min- 26.2 Two Step Exposure—Classify imum of 4 h before evaluation. lightfastness of the material by: 29. Precision (c) determination of the number of 24. Assessment of Color Change AATCC Fading Units required to pro- 29.1 In 2002 a single laboratory study 24.1 Compare the exposed portion to duce color changes in the test specimen was performed using a single operator. the masked control or to an unexposed equal to both a Step 4 and Step 3 on the This study was intended to be a tempo- original portion of the specimen, as spec- AATCC Gray Scale for Color Change rary table of variances to give some indi- ified in a material specification or pur- (see Table II). cation of test variability. A complete in- chase order. Complete characterization of 26.2.1 Assign both classifications: the terlaboratory study is to be conducted in the lightfastness of a test specimen requires evaluation at more than one level of exposure (see 32.15). 24.2 Quantify the color change using either the AATCC Gray Scale for Color Table IV—Classification by AATCC Blue Wool Lightfastness Standards Above L7 Change (preferred), or by colorimetric Number of L7 Standards Exposed measurement of color difference at the Equivalent AATCC specified exposure level whether in Equal To But Not Lightfastness Fading Unit AATCC Fading Units, kilojoules of radi- Less Than Greater Than More Than Class (AFU) ant energy, or compared to a reference —2—L8320 standard (see 32.22). 3—2L8-9— 24.3 Determine total color difference —3—L8-9480 ∆ 4—3L8-9— ( ECIELAB) and the difference in lightness, chroma, and hue (∆L*, ∆C*, ∆H*). Use —4—L9640 instruments that provide values based on 5—4L9-10— the CIE 1976 equation using illuminant — 5 — L9-10 800 6—5L9-10— D65 and 10° observer data. For instruments with diffuse geometry, include the — 6 — L9-10 960 7—6L9-10— specular component of reflectance in the — 7 — L9-10 11200 measurements (refer to AATCC Evalua- 8—7L9-10— tion Procedure 6, Instrumental Color — 8 — L10 12800 Measurement). a etc.a a etc.a a etc.a aetc.a0

25. Acceptance Based on Simultaneous a A classification increase of 1 represents the interval when the equivalent AATCC Fading Units are doubled Exposure of a Reference Specimen 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 25.1 Assess color change of the mate- that interval.

AATCC Technical Manual/2006 TM 16-2004 29

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:

AATCC 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 Option 6 only 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 ______

30 TM 16-2004 AATCC Technical Manual/2006

Copyright © 2005 American Association of Textile Chemists and Colorists the near future for the purposes of preci- 31.5 ASTM G 24, Standard Practice Thermometers. sion and bias. Table values do not reflect for Conducting Exposures to Daylight 32.2.1 For Black Panel Thermometers: different types of material tested to this Filtered through Glass (see 32.19). Testing temperature is measured and regulated standard. Between-Laboratory variabil- 31.6 ASTM G 155, Standard Practice by a Black Panel Thermometer unit mounted ity is not indicated either. Special care on the specimen rack to permit the face of it to for Operating Xenon-Arc Light Appara- receive the same exposure as the test speci- and consideration of the variances re- tus for Exposure of Nonmetallic Materi- men. Black Panel Thermometers shall consist ported must be used when examining test als (see 32.19). of a metal panel at least 70 × 150 mm and not variability problems. 31.7 ISO 105, Part B, Textiles—Tests less than 45 × 100 mm whose temperature is 29.1.1 Samples tested consisted of four for Colorfastness (see 32.20). measured with a thermometer or thermocou- fabrics, with three replicates each. Expo- ple whose sensitive portion is located in the sure conditions were those found in Op- 32. Notes center of and in good contact with the panel. tion 3 of this method. Each sample was The side of the panel facing the light source evaluated instrumentally three times and 32.1 AATCC Blue Wool Lightfastness shall be black with a reflectance of less than Standards, except L2, are specially prepared 5% throughout the spectrum of light reaching averages were calculated. The data is the specimen; the side of the panel not facing found in Table VI. by blending varying proportions of wool dyed with a very fugitive dyestuff, Erio Chrome the light source shall be open to the atmo- 29.1.2 Within-laboratory standard er- Azurole B (C.I. 43830) and wool dyed with a sphere within the exposure chamber. rors and Sample Variance are shown in fast dyestuff, Indigosol Blue AGG (C.I. 32.2.2 For Black Standard Thermometers: Table VII. Data is on file at the AATCC 73801). Each resultant higher numbered stan- Testing temperature is measured and regulated Technical Center. dard is twice as colorfast as the preceding by a black standard thermometer unit mounted numbered standard. AATCC Blue Wool on the specimen rack to permit the face of it to receive the same exposure as the test speci- 30. Bias Lightfastness Standards and the ISO numbered Blue Wool Lightfastness Standards (as men. The Black Standard Thermometer shall consist of a plane of stainless steel plate mea- 30.1 The colorfastness to natural and used in ISO 105-B01) produce different rat- ings and therefore cannot be used interchange- suring 70 × 40 mm with a thickness of about artificial light can be defined only in ably (see 32.5). 0.5 mm, whose temperature is measured by a terms of a test method. There is no inde- 32.2 Black Thermometers are used to con- thermal resistor, with good heat-conducting pendent method for determining the true trol an artificial weathering device and to pro- properties, fitted to the reverse side. The metal value. As a means of estimating this vide an estimate of the maximum temperature plate is fixed to a plastic plate so that it is ther- property, the method has no known bias. of samples exposed to a radiant energy source. mally insulated. The side of the panel facing There are two types of Black Thermometers. the light source shall be black with a reflectance of less than 5% throughout the spectrum 31. References One type is referred to as a “Black Panel Ther- mometer” which is uninsulated and is made of of light reaching the specimen. metal. The other type is referred to as a “Black 32.3 The Xenon Reference Fabric is a knit 31.1 AATCC Evaluation Procedure 1, of 150 denier textured polyester yarn in a dou- Gray Scale for Color Change (see 32.5). Standard Thermometer” which is insulated and is made of metal with a plastic backing. ble pique stitch, dyed to a purple shade with 31.2 AATCC Evaluation Procedure 6, As a point of information, some ISO specifi- 1.8% of 2,4-dinitro-6-bromo-2-amino-4— Instrumental Color Measurement (see cations specify the use of a “Black Standard (N,N-diethylamino) azobenzene at 129°C 32.5). Thermometer.” Typically, Black Standard (265°F) for 1 h and then heat set at 179°C 31.3 ASTM G 151, Standard Practice Thermometers indicate higher temperatures (335°F) for 30 s (see 32.6). for Exposing Nonmetallic Materials in than Black Panel Thermometers under the 32.4 More uniform and reproducible fading Accelerated Test Devices that Use Labo- same exposure conditions. of the AATCC Blue Wool Lightfastness Stan- dards, Xenon Reference Fabric, and test speci- ratory Light Sources. The Black Thermometer units indicate the absorbed irradiance minus the heat dissipated mens is achieved when backed with white 31.4 ASTM G 153, Standard Practice by conduction and convection. Keep the black cardboard. The color difference values in the for Operating Enclosed Carbon-Arc face of these thermometer units in good condi- initial determination of the end point for both Light Apparatus for Exposure of Non- tion. Follow the manufacturer’s recommenda- the Xenon Reference Fabric and the AATCC metallic Materials (see 32.19). tions for proper care and maintenance of Black Blue Wool Lightfastness Standards were determined from exposures with such backing. Although tolerances are given for both the AATCC Blue Wool Lightfastness Standards and Xenon Reference Fabric, every effort ∆ should be made to achieve the midpoint value Table VI— E given for these standards. For referee purposes, the Xenon Reference Fabric and Brown #1 Brown #2 Green Blue AATCC Blue Wool Lightfastness Standards Sample 1 0.61 1.05 2.41 2.04 will be exposed in multiples of three and the Sample 2 0.92 1.16 3.18 2.65 average color difference in the case of the Xe- Sample 3 0.56 1.79 2.59 2.10 non Reference Fabric will be 20 CIELAB Average 0.697 1.333 2.727 2.263 units and in the case of the AATCC Blue Wool Lightfastness Standards will be 1.7 CIELAB units. Table VII—Within-Laboratory Standard Errors and Sample Variance 32.5 Available from AATCC, P.O. Box 12215, Research Triangle Park NC 27709; Sample tel: 919/549-8141; fax: 919/549-8933; e-mail: Identification Standard Dev. Standard Error Sample Variance 95% Confidence [email protected]. 32.6 The Xenon Reference Fabric Standard Brown #1 0.195 0.1125956 0.0380333 0.4844603 of Fade is used as a visual or instrumental ref- Brown #2 0.399 0.2305308 0.1594333 0.9918946 erence for test chamber temperature verifica- Green 0.403 0.2325463 0.1622333 1.0005666 tion. The measured instrumental color Blue 0.336 0.1941076 0.1130333 0.8351784 difference value will be shown on each standard of fade. The Xenon Reference Fabric is *Note: Because the interlaboratory test included less than five laboratories, estimates of standard error and sensitive to temperature as shown in Table sample variance may be either underestimated or overestimated to a considerable extent and should be VIII. used with special caution. The values should be viewed as minimal data with regards to precision. Confi- 32.7 Precut white card stock for backing dence intervals are not well established. test specimens is available from SDL Atlas

AATCC Technical Manual/2006 TM 16-2004 31

Copyright © 2005 American Association of Textile Chemists and Colorists Table VIII—Temperature vs. Color Change, 61st Edition, 1980, edited by Robert C. Weast; different results may be obtained with the Xenon Reference Fabrica The Chemical Rubber Co., Cleveland OH. same amount of radiant energy in daylight ex- 32.13.2 International Commission on Illu- posures made at different times and in differ- Black-Panel ∆E mination (CIE) Publication No. 20, 1972. ent locations. Temperature (CIELAB) 32.13.3 Atlas Sun Spots, Vol. 4, No 9, 32.17 The Eppley PS-P black and white Spring 1975, Atlas Material Testing Technol- pyranometer has been found suitable for mea- 58°C 16.0 ogy LLC, Chicago, IL. suring total daylight radiant energy, and the 63°C 20.0 32.14 Window glass of the desired quality Eppley Broad Band-Pass Ultraviolet Radiom- 68°C 23.8 is available from such dealers as: Libby- eter has been found suitable for measuring the Owens-Ford Glass Co., Toledo OH, 2.0 mm radiant energy from 295-385 nm of daylight. a see Note 32.9. flat drawn sheet glass, single strength, quality These instruments are available from Eppley B; or Pittsburg Plate Glass Co., Pennvernon Laboratory, 12 Sheffield Ave., Newport RI sheet glass, single strength, quality B, or 02840; tel: 401/847-1020. The Atlas LM-3A equivalent. narrow band-pass radiometer has been found 32.14.1 In order to reduce variability due to suitable for measuring radiant energy at 340 or L.L.C., 1813A Associate Lane, Charlotte NC changes in UV transmission of glass, all new 420 nm of daylight and is available from SDL 28217; tel: 704/329-0911; fax: 704/329-0914; glass shall be exposed facing the equator, at Atlas L.L.C., 1813A Associate Lane, Char- e-mail: [email protected]. Comparable white the site latitude angle, or on an empty under lotte NC 28217; tel: 704/329-0911; fax: 704/ card stock (9016 White Bristol Index) is also glass exposure cabinet, for at least three 329-0914; e-mail: [email protected]. The available from stationery stores and dealers in months prior to installation in test cabinets. Radialux broad bandpass radiometer has been artist’s supplies. 32.14.2 After the three-month exposure pe- found suitable for measuring radiant energy 32.8 Test masks made with white paper, riod, it is recommended that the spectral trans- from 300-400 nm of daylight and is available 0.005-0.006 inches thick, with a dull black mittance of representative samples from each from SDL Atlas L.L.C., 1813A Associate coating that provides zero light transmittance lot of glass be measured. Typically “single Lane, Charlotte NC 28217; tel: 704/329-0911; to the specimen are available from SDL Atlas strength” glass will have a transmittance of fax: 704/329-0914; e-mail: info@sdlatlas. L.L.C., 1813A Associate Lane, Charlotte NC 10-20% at 320 nm and at least 85% at wave- com. 28217; tel: 704/329-0911; fax: 704/329-0914; lengths of 380 nm or higher after the three- 32.18 Interlaboratory Test Summary— e-mail: [email protected]. month pre-aging procedure. If transmittance Committee RA50 has conducted extensive 32.9 One or more of the test apparatus types of the glass is measured, report the average for studies to evaluate the use of radiation moni- and materials are available from: SDL Atlas at least three pieces of the lot of glass being toring devices to terminate exposures in light- L.L.C., 1813A Associate Lane, Charlotte NC tested. Follow the instructions for measure- fastness testing. Data has been collected in 28217; tel: 704/329-0911; fax: 704/329-0914; ment of transmittance of solid samples recom- interlaboratory studies using controlled irradi- e-mail: [email protected]; and Suga Test In- mended by the manufacturer of the UV-visible ance, xenon-arc equipment and in daylight ex- strument Co., 4-14 Shinjuku, 5-Chome, Tokyo spectrophotometer used. If a spectrophotome- posures conducted during a two-year period in 160, Japan; tel: +81(3) 3354-5241; fax: +81(3) ter with an integrating sphere is used, the mea- both Arizona and Southern Florida. In both 3354-5275. surements shall be performed in accordance studies, one laboratory conducted instrumen- 32.10 Available from William Harrison with ASTM E 903, Test Method for Solar Ab- tal measurement of the color change for all ex- Co., 4595 E. 10th Ct., Hialeah FL 33013; tel: sorptance, Reflectance, and Transmittance of posed specimens. 305/681-8381. Materials Using Integrating Spheres. Addi- The interlaboratory studies were under- 32.11 Pile fabric, such as carpets, which tional information on this subject is contained taken, using eight different lightfastness stan- have fibers that may shift position, or texture in the following ASTM paper by W. D. Ketola dard fabrics, to determine the definition of 20 which may make evaluations in small areas and J. S. Robbins: “UV Transmission of Sin- AATCC Fading Units in terms of measured difficult should be tested with an exposed area gle Strength Window Glass,” Accelerated and radiation. These studies showed that accept- of not less than approximately 40.0 × 50.0 mm Outdoor Durability Testing of Organic Mate- able agreement between laboratories can be (1.6 × 2.0 in.). Expose sufficient size or multi- rials, ASTM STP 1202, Warren D. Ketola and obtained for lightfastness testing providing the ple specimens to include all colors in the Douglas Grossman, Eds., American Society following variables are controlled: irradiance sample. for Testing and Materials, Philadelphia, 1993. level, black-panel temperature, ambient tem- 32.12 Sample frames must be made of 32.15 A difference in color between origi- perature and relative humidity. Overall, there stainless steel, aluminum, or suitably coated nal material and the covered portion of the ex- was less than 10% variability in the instru- steel to avoid contaminating the specimens posed specimen indicates that the textile has mentally determined color change of speci- with metallic impurities that might catalyze or been affected by some agent other than light, mens exposed in different laboratories. For all inhibit the degradation. When samples are such as heat or a reactive gas in the atmo- specimens tested the standard deviation was fastened with staples, they should be of the sphere. Although the exact cause of this differ- equivalent to less than one-half step on the nonferrous type overcoated to avoid contami- ence in color may not be known, it should be Gray Scale for Color Change. As a result of nation of the specimen by corrosion products. noted in the report when it occurs. these tests, 20 AATCC Fading Units was es- Metal frames must have a dull finish and be 32.16 In some cases high humidity, in com- tablished at 85 KJ/(m2nm) when measured at designed to avoid reflectances that could in- bination with atmospheric contaminants, has 420 nm (approximately 21.5 continuous light– fluence the performance of the material. been found to produce color changes as great on operating hr) when tested at the conditions Frames shall conform to the curvature of the as those produced by light. When requested, specified for Xenon-Arc Lamp, Continuous specimen rack. The size of the frame is deter- prepare a duplicate set of test specimens and Light, Option 3 mined by the type specimens required for indi- standards mounted on cardboard, but not For the daylight studies, 16 different fab- vidual property requirements. masked, and expose simultaneously in another rics, in addition to AATCC and ISO Blue 32.13 In Table C1, the data are for a typical cabinet of the same type used in the light ex- Wool Lightfastness standard fabrics, were ex- spectral power distribution for an enclosed posures but with the glass covered with an posed. An exposure series was begun each carbon-arc with a borosilicate glass globe. The opaque material so that the light is excluded. quarter year at two locations over a two-year daylight data are for global irradiance on a Since there is a combined effect of light, tem- period. Exposures were terminated based on horizontal surface with an air mass of 1.2, col- perature, humidity and atmospheric contami- instrumental measurement of radiant energy umn ozone 0.294 atm cm, 30% relative hu- nants, it cannot be assumed that a comparison dosage. A wide variation in climatic condi- midity, altitude 2100 m (atmospheric pressure between specimens exposed in the covered tions was encountered during the test period. of 787.8 mb), and an aerosol represented by an cabinet and in the uncovered cabinet under The data obtained clearly shows that the color optical thickness of 0.081 at 300 nm and 0.62 glass will permit separating the effects pro- change of individual specimens is affected dif- at 400 nm. Data from 701-800 nm is not duced by light only. However, a comparison ferently by variations in temperature, humid- shown. of the two sets of specimens with a piece of ity, atmospheric contaminants, etc.; however, The following references provide back- the original which has not been in an exposure the single most significant variable is radia- ground information on radiation measure- cabinet will indicate whether a material is sen- tion. The variation in color change resulting ments by Light Control Systems: sitive to moisture and atmospheric contami- from exposure during different years, loca- 32.13.1 Handbook of Chemistry & Physics, nants. This may also help to explain why tions, and seasons, averaged ± 30%.

32 TM 16-2004 AATCC Technical Manual/2006

Copyright © 2005 American Association of Textile Chemists and Colorists A more detailed summary of these test re- A2 The design of the test chamber may shorter than 310 nm must be used to sim- sults was presented to the 14th meeting of vary, but it should be constructed from ulate daylight filtered through window ISO, Technical Committee 38, Subcommittee corrosion resistant material. glass. 1 as Document 38/1 N 993, USA Report on A3 Xenon-Arc Light Source. The The instrument manufacturers’ recom- Monitoring of Radiation during Lightfastness Testing. xenon-arc test apparatus utilizes a long- mendations should be used to provide the 32.19 Available from ASTM, 100 Barr arc quartz-jacketed xenon-arc lamp as the appropriate spectrum (see A3.4 below). Harbor Dr., West Conshohocken PA 19428; source of irradiance which emits radia- Replace filters when chipped, cracked, or tel: 610/832-9500; fax: 610/832-9555. tion from below 270 nm in the ultraviolet when discoloration or milkiness devel- 32.20 Available from American National through the visible spectrum and into the ops. Discard xenon lamp tubes and filters Standards Institute, Inc., 11 W. 42nd St., 13th infrared. at the manufacturer’s recommended time Fl., New York NY 10036; tel: 212/642-4900; While all of the xenon-arc lamps are of intervals or sooner, or when 20 AATCC fax: 212/302-1286. the same general type, different size Fading Units can no longer be attained in 32.21 For measuring temperature and rela- lamps operated in different wattage 20 ± 2 continuous light-on operating tive humidity of the air under the same condi- ranges are employed in several sizes and (clock) hours. tions that the samples and reference materials types of apparatus. In each of the various A3.3 Spectral Irradiance of Filtered are exposed and in the vicinity of test cabinets, models, the diameter and height of the Xenon-Arc—Figure A1 shows the de- any suitable indicating or recording instrument may be used. Continuous recording of specimen rack varies according to the sired relative spectral power distribution temperature and relative humidity is preferred. lamp size and the wattage at which it is for filtered xenon-arcs comply with these 32.22 An automated electronic grading sys- operated to provide an irradiance at the limits. The acceptable limits for variation tem may be used as long as the system has face of the specimen of 1.10 ± 0.03 W/ of the relative spectral power distribution been demonstrated to provide results that are (m2nm) measured at 420 nm or equiva- shown in Fig. A1 are on file at the equal to and provide equal or better repeatabil- lent when exposed in standard holders. AATCC Technical Center. ity and reproducibility than an experienced A3.1 Aging of the xenon burners or fil- A3.4 Follow the device manufacturer’s grader performing visual evaluations. ters can result in changes in lamp spec- instructions for recommended mainte- trum. Changes in lamp spectrum may also nance. Appendix A be caused by accumulation of dirt or other residue in or on the burner envelope. Appendix B A. Xenon-Arc Lamp Fading Apparatus A3.2 Filter—In order for xenon-arcs to simulate terrestrial daylight, filters must B. Daylight Exposure Cabinet and Location A1 Different types of xenon-arc test be used to remove short wavelength UV apparatus may be utilized provided that radiation. In addition, filters to remove B1 The daylight exposure cabinet shall the test apparatus is capable of automati- infrared radiation may be used to prevent consist of a glass-covered enclosure of cally controlling irradiance level, humid- unrealistic heating of test specimens that any convenient size constructed of metal, ity level, chamber air temperature, and can cause thermal degradation not experi- wood or other satisfactory material to Black Panel or Black Standard Ther- enced during outdoor exposures. Filters protect the specimens from rain and mometer temperature. to reduce irradiance at wavelengths weather, and be well ventilated to allow

4.50

4.00

3.50

3.00 nm) 2 2.50

2.00

Irradiance (W/(m 1.50

1.00

0.50

0.00 280 320 360 400 440 480 520 560 600 640 680 720 760 800 wavelength (nm)

Fig. A1—Filtered Xenon Lamp Spectral Power Distribution Controlled at 1.1 W/(m2nm) at 420 nm

AATCC Technical Manual/2006 TM 16-2004 33

Copyright © 2005 American Association of Textile Chemists and Colorists free flow of air over the specimens. The the ground cover in that climatological filters are borosilicate glass globes which glass cover shall be a sheet 2.0-2.5 mm area. In desert areas, it should be gravel fit around the carbon burners. thick piece of good grade, clear and flat- whereas in most temperature and sub- C1.3 The emission spectra of the en- drawn. It shall be single strength, free of tropical areas, it should be low cut grass. closed carbon-arc shows strong emission bubbles or other imperfections. The type of ground cover should be indi- in the long wavelength ultraviolet region. B2 The enclosure or cabinet shall be cated in the report. Emissions in the visible, infrared and equipped with a rack which supports the B6 Instruments for determining clima- short wavelength ultraviolet below 350 specimens in a plane parallel to that of tological data during the exposure period nm are generally weaker than in daylight the glass cover with the face of the speci- shall be operated in the immediate area of behind window glass (see Table C1). The men at a distance below it of not less than the exposure cabinets. When requested, enclosed carbon-arc does not provide a 75.0 mm (3.0 in.). The specimen mount- data obtained shall be reported as part of good match to natural daylight. ing rack shall be constructed of a material the results of the test. To characterize the C1.3.1 Spectral Irradiance for En- that is compatible with the test speci- conditions around the test frame, these closed Carbon-Arc with Borosilicate Fil- mens. It may be either the open type pro- instruments should be capable of record- ters—Table C1 is representative of the viding good ventilation on the back side ing: ambient temperature (daily mini- spectral irradiance received by a test of the specimen, or of a solid material as mum and maximum), relative humidity specimen mounted in the specimen plane. required. To minimize shadows from the (daily minimum and maximum), hours of C1.4 See 32.13 for additional informa- top and the sides of the cabinet, the us- precipitation (rain), and total hours of tion. able exposure area under glass shall be wetness (rain and dew). To characterize C1.5 Thermometer—A Black Panel or limited to that of the glass cover reduced the conditions within the test frame, these Black Standard Thermometer may be by twice the distance from the cover to instruments should be capable of record- used and shall conform to the descrip- the specimens. ing: ambient temperature under glass tions found in 32.2.1 and 32.2.2. The type B3 The cabinet shall be located where (daily minimum and maximum), black of thermometer used, the method of it will receive direct daylight throughout temperature sensor under glass, total ra- mounting on specimen holder, and the the day and where shadows of objects in diant energy and ultraviolet radiant en- exposure temperature shall be stated in the vicinity will not fall upon it. When ergy (either broad or narrow bandpass) at the test report. the cabinet is installed over soil, the dis- the same angle of exposure as the test C1.6 Relative Humidity—The test tance between the bottom of the cabinet specimens, and relative humidity (daily chamber may be equipped with a means and the plane of the cleared area shall be minimum and maximum) (see 32.17 and to measure and control the relative hu- great enough to prevent any undesirable 32.21). midity. Such instruments shall be effects of contact with grass or other shielded from the light source. plant growth during the period of expo- Appendix C C1.7 Apparatus Maintenance—The sure. test apparatus requires periodic mainte- B4 The glass cover and the test speci- C. Enclosed Carbon-Arc Lamp Fading nance to maintain uniform exposure con- men shall slope toward the equator at an Apparatus ditions. Perform required maintenance in angle from the horizontal equal in de- accordance with manufacturer’s instruc- grees to approximately the latitude of the C1. Different types of carbon-arc test tions. location at which the tests are being apparatus may be utilized. The design of made. Other angles of exposure, such as the test chamber may vary, but it should 45° may be used, but the angle must be be constructed from corrosion resistant Table C1—Typical Spectral Power material, and in addition to the radiant reported in the results of test. Distribution for Enclosed Carbon-Arc with B5 Exposure cabinets shall be located source, may provide for means of Borosilicate Filters. Ultraviolet Wavelength in cleared areas, preferably at a suitable controlling temperature and relative Region Irradiance as a Percentage of Total humidity. number of climatologically different sites Irradiance from 300-400 nm representing the various conditions under C1.1 Laboratory Light Source—En- which the material will be used. Major closed carbon-arc light sources typically Enclosed climatological variations include subtrop- use carbon rods which contain a mixture Carbon-Arc ical, desert, seashore (salt air), industrial of metal salts. An electric current is with atmosphere and areas exhibiting a wide passed between the carbon rods which Borosilicate range in percentage of available sun- burn and give off ultraviolet, visible and Bandpass (nm) Filters Sunlight shine. The area beneath and in the vicin- infrared radiation. Use carbon rods rec- 290-320 20.0% 5.6% ity of the cabinets should be character- ommended by the device manufacturer. 320-360 20.5% 40.2% ized by low reflectance and be typical of C1.2 Filter—The most commonly used 360-400 79.5% 54.2%

34 TM 16-2004 AATCC Technical Manual/2006