1、Designation: D 4303 06Standard Test Methods forLightfastness of Colorants Used in Artists Materials1This standard is issued under the fixed designation D 4303; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 Four test methods to accelerate the effects of long termindoor illumination on artists materials are described below.One of the
3、natural daylight methods and one of the xenon-arcmethods are used to categorize the lightfastness of colorants.1.1.1 Test Method AExposure in southern Florida tonatural daylight filtered through window glass.1.1.2 Test Method BExposure in Arizona to natural day-light filtered through window glass.1.
4、1.3 Test Method CExposure in a non-humidity con-trolled xenon-arc device simulating daylight filtered throughwindow glass.1.1.4 Test Method DExposure in a humidity controlledxenon-arc device simulating daylight filtered through windowglass.1.2 These test methods are used to approximate the colorchan
5、ge that can be expected over time in colorants used inartists materials exposed indoors to daylight through windowglass.NOTE 1The color changes that result from accelerated exposure maynot duplicate the results of normal indoor exposure in a home, art gallery,or museum. The relative resistance to ch
6、ange, however, can be establishedso colored materials can be assigned to categories of relative lightfastness.NOTE 2Users who wish to test colored materials under fluorescentillumination should consult Practice D 4674.1.3 Lightfastness categories are established to which colo-rants are assigned base
7、d on the color difference betweenspecimens before and after exposure.1.4 Color difference units are calculated by the CIE 1976L*a*b* color difference equation.1.5 These test methods apply to colored artists materials.1.6 The values stated in SI units are to be regarded as thestandard. The values giv
8、en in parentheses are for informationonly.1.7 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitatio
9、ns prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD 4302 Specification for Artists Oil, Resin-Oil, and AlkydPaintsD 4674 Practice for Accelerated Testing for Color Stability
10、of Plastics Exposed to Indoor Office EnvironmentsD 5067 Specification for Artists Watercolor PaintsD 5098 Specification for Artists Acrylic Dispersion PaintsD 5724 Specification for Gouache PaintsD 6901 Specification for Artists Colored PencilsE 284 Terminology of AppearanceE 1347 Test Method for Co
11、lor and Color-Difference Mea-surement by Tristimulus (Filter) ColorimetryE 1348 Test Method for Transmittance and Color by Spec-trophotometry Using Hemispherical GeometryE 1349 Test Method for Reflectance Factor and Color bySpectrophotometry Using Bidirectional (45:0 or 0:45)GeometryG24 Practice for
12、 Conducting Exposures to Daylight Fil-tered Through GlassG113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 141 Guide forAddressing Variability in Exposure Testingof Nonmetallic MaterialsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test
13、 Devices that Use Laboratory Light SourcesG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials3. Terminology3.1 DefinitionsAppearance terms used in these test meth-ods are defined in Terminology E 284. Terms relating to naturaland artificial lightfastness test
14、s are defined in TerminologyG113.3.1.1 glass, nas used in these test methods, glass refers tosingle-strength window glass.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D0
15、1.57 on Artist Paints and Related Materials.Current edition approved July 1, 2006. Published July 2006. Originally approvedin 1983. Last previous edition approved in 2003 as D 4303 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm
16、.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Methods4.1 Color measurements are made on d
17、uplicate specimensthat have been prepared as directed in the specification for thatmaterial. Examples of specifications are: D 4302, D 5067,D 5098, D 5724, and D 6901. Each contains colorants in adifferent vehicle. The measurements are recorded for compari-son with readings made after the specimens
18、have been ex-posed.4.2 Lightfastness is determined by exposing the specimensto daylight filtered through glass outdoors either in southernFlorida or in Arizona and also to xenon arc radiation through awindow glass filter.4.3 The colorants are classified by the amount of colorchange calculated as DE*
19、 units in accordance with PracticeD 2244.4.4 Variations in test results can be due to differences inspecimen preparation, surface irregularities, color measure-ments and conditions of exposure. Allowance for these varia-tions is made by assigning a wide range of color change n eachof the five lightf
20、astness categories. Colorants are placed in oneof these categories based on the mean of the DE* valuesobtained from two or more types of exposure. Only colorantsthat place in the first two categories conform to the require-ments of this standard.5. Significance and Use5.1 The retention of chromatic
21、properties by a colorant overa long period of years is essential in a work of art. Acceleratedexposure simulates color changes that may reasonably beexpected. The producer and the user of artists materials,therefore, can be apprised of suitable colorants.5.2 Variations in results may be expected bet
22、ween the testmethods.Also, some variation may be expected when the sametest is repeated. Variations in Methods A and B are due todifferences in outdoor conditions that are not accounted for intesting to equivalent radiant exposures. Information on sourcesof variability and strategies for addressing
23、variability in labo-ratory accelerated exposure tests is found in Guide G 141.5.3 This standard does not cover factors other than light-fastness that can affect the permanence of art materials.6. Apparatus6.1 Outdoor Exposure Facilities as described in PracticeG24, using an exposure angle of 45, fac
24、ing the equator.6.2 Xenon-Arc Lightfastness Apparatus as described inPractice G 155.6.3 Spectrophotometer, abridged spectrophotometer orcolorimeter capable of excluding specular reflectance in itsmeasurement.7. Procedure7.1 Prepare seven specimens of the art materials to betested, following the dire
25、ctions given in the appropriate speci-fication. If there is no specification for the art material, sevenspecimens must be prepared that are as similar, uniform, andopaque as possible.7.1.1 Two specimens of each color shall be exposed in eachof two test methods, either A or B and either C or D. Onesp
26、ecimen of each color shall be retained for a visual compari-son with the test specimens following exposure, and twospecimens shall be retained for use in a third exposure ifneeded.7.1.2 The retained, unexposed specimens are stored in thedark unless the formulation contains oil. Store specimens thatc
27、ontain oil in a light level of 500 to 700 lux (50 to 75 fc) toprevent yellowing. If specimens must be stored for as long as100 days, store all specimens in the dark, but remove thosecontaining oil and place in the light level specified above toprevent yellowing for at least 7 days before measurement
28、 orvisual evaluation.7.1.3 Cut the specimen to a size that will fit the holder to beused for exposure and the port of the color measuring instru-ment.7.1.4 Determine if test specimens are opaque. Colors mixedwith white, as described in the specifications for artists paints,are opaque. Other material
29、s must be applied over both a blacksubstrate and a white substrate to determine opacity. Anymeasured color difference between the color over black andover white indicates a lack of opacity.7.1.4.1 A measurement representative of the whole speci-men must be obtained if the specimen is not opaque. To
30、get arepresentative measure of the color, both before and afterexposure. either (1) use a large measuring port of 25 mm (1 in.)diameter, or (2) using a small port, obtain the mean of a numberof measurements of various areas of the specimens, andcompare it with the mean of a second set of measurement
31、s ofdifferent areas. If the means agree, use that value as therepresentative color. Otherwise, repeat the procedure untilagreement is obtained.7.2 Immediately before exposure, measure all test speci-mens using a spectrophotometer or spectrocolorimeter (seeTest Method E 1348 or E 1349) or colorimeter
32、 (see TestMethod E 1347) using Illuminant D65 and the 1964 10Observer and excluding specular reflection from the measure-ment. Record the CIELAB measurement data.7.2.1 Measure specimen panels with any brush marks in thesame direction and measure the same area of the panel beforeand after each exposu
33、re interval. If the design of the instrumentallows, three readings at different locations on the panel shouldbe made and the mean calculated. If feasible, mark on the backof the specimen the spot(s) measured, and remeasure thesesame spots following exposure.7.3 Expose duplicate specimens in each of
34、two test meth-ods, outdoor Test Method A or B and xenon arc Test Method Cor D, as described below:7.3.1 Test Method AExposure in Southern Florida Below27 Latitude to Natural Daylight Filtered Through WindowGlassTest Method A can be used for under glass outdoorexposure if the material is an oil paint
35、 or acrylic dispersionpaint on an aluminum substrate.7.3.1.1 Mount duplicate specimens of each color on an opensided rack under glass and expose in southern Florida at a 45degree angle to the horizontal facing south during Octoberthrough May to a total global solar (290 to 2500 nm) radiationdose of
36、1260 MJ/m2incident on the glass, in accordance withPractice G24.D43030627.3.2 Test Method BExposure in Arizona to Natural Day-light Filtered Through Window GlassUse Test Method B ifthe test specimens are prepared on a paper substrate or thevehicle is affected by the combination of high moisture cont
37、entand temperature fluctuations that are characteristic of southFlorida. Examples are watercolor and gouache paints, coloredpencils, colored water-thinned inks, and pastels.7.3.2.1 Mount duplicate specimens in an enclosed black boxwith a small fan to circulate the air and expose in Arizona at a45 de
38、gree angle to the horizontal facing south during Octoberthrough May to a total global solar (290 to 2500 nm) radiationdose of 1260 MJ/m2incident on the glass, in accordance withPractice G247.3.3 Test Method CExposure Simulating Daylight Fil-tered Through Window Glass in a Xenon Arc Device That DoesN
39、ot Control the Relative HumidityThis method will gener-ally have a low relative humidity.7.3.3.1 Use a xenon-arc device that conforms to the require-ments defined in Practices G 151 and G 155. Unless otherwisespecified, the spectral power distribution of the xenon-arc shallconform to the requirement
40、s in Practice G 155 for xenon arcradiation through a window glass filter.(a) Place specimens in the test device in positions thatconform with specifications in Practice G 151 or use theprocedures described in this practice that either ensure equalradiant exposure on all specimens or compensate for i
41、rradiancedifferences within the exposure chamber. To assure equalradiant exposure it may be necessary to reposition specimensduring exposure.7.3.3.2 Unless agreed otherwise, set the irradiance at thecontrol point to 0.35 6 0.02 at 340 nm and expose specimensto 100 % light to reach a total radiant ex
42、posure of 510kJ/(m2nm) at 340 nm, the equivalent to 1260 MJ/m2of totalsolar radiation. For a xenon-arc device that controls exposureat 300 to 800 nm, set the irradiance at the control point to 500W/m2and expose to 100 % light to reach a total radiantexposure of 739 MJ/m2at 300 to 800 nm. For xenon a
43、rcdevices that control exposures in a different spectral region,consult the manufacturer of the device for the irradiance andradiant exposure required to produce equivalent test results.7.3.3.3 The uninsulated black panel temperature shall be 636 2C. For the equivalent insulated black panel temperat
44、ure,consult the manufacturer of the device.NOTE 3The set points specified for irradiance, temperature andhumidity are the target conditions for the sensor programmed by the userat the control point. Therefore, when a standard calls for a particular setpoint, the user programs that exact number. The
45、operational fluctuationspecified with the set point does not imply that the user is allowed toprogram a set point higher or lower than the exact set point specified.Operational fluctuation is determined by the machine variable and is themaximum deviation allowable from the set point of the sensor at
46、 thecontrol point during equilibrium conditions.NOTE 4To track the rate of color change in the xenon arc exposure,the total exposure time can be divided into three or more phases and thedevice programmed to stop at the end of each phase so the specimens canbe measured and recorded. Then specimens ar
47、e returned to the testchamber and exposure continues until the total required amount ofirradiation is reached.7.3.4 Test Method DExposure Simulating Daylight Fil-tered Through Window Glass in a Humidity Controlled Xenon-Arc DeviceThis environment will typically have higherrelative humidity than Test
48、 Method C:7.3.4.1 Follow 7.3.3.1.7.3.4.2 Mount specimens in unbacked holders and followstep (a) in 7.3.3.1. It is recommended that all unused spaces inthe specimen exposure area be filled with blank metal panelsthat are not highly reflective.7.3.4.3 Follow 7.3.3.2.7.3.4.4 Follow 7.3.3.3.7.3.4.5 Set
49、the relative humidity at the control point in thetest chamber to 55 6 5 % RH.7.3.4.6 In machines that allow control of chamber airtemperature, it shall be set at 43 6 2C.NOTE 5Duplicate specimens should not be placed near one anotherduring the exposures.NOTE 6It has been found that Alizarin Crimson and other colorantsare affected differently when exposed to a light/dark cycle rather than tocontinuous light. Dark periods are characteristic of exposure to daylight aswell as to indoor lighting. Therefore, when mutually agreed upon, thefollowing alt
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