1、Designation: C1649 08C1649 14Standard Practice forInstrumental Transmittance Measurement of Color for FlatGlass, Coated and Uncoated1This standard is issued under the fixed designation C1649; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice provides guidelines for the instrumental transmittance measurement of the color of
3、coated and uncoatedtransparent glass. See Terminology E284.1.2 The practice specifically excludes fluorescent and iridescent samples.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to ad
4、dress all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2244 Practice
5、 for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color CoordinatesE284 Terminology of AppearanceE179 Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of MaterialsE308 Practice for Computing the Colors of Obje
6、cts by Using the CIE SystemE1164 Practice for Obtaining Spectrometric Data for Object-Color EvaluationE1348 Test Method for Transmittance and Color by Spectrophotometry Using Hemispherical Geometry2.2 CIE Standard:3CIE 15:2004 Colorimetry3. Summary of Practice3.1 The color of transparent glass is me
7、asured in the total transmittance mode on a CIE-conforming diffuse instrument. (SeeGuide E179 and Test Method E1348.) The glass color is expressed in CIE tristimulus values based on spectral transmittancemeasurements over the full CIE spectral range of 350 780 nm with a maximum 10-nm band pass. (See
8、 CIE 15:2004 and PracticeE308.) For color measurement, use of a truncated spectral range of 400 700 nm is acceptable. (See CIE 15:2004.) Furtherinformation on the UVabsorbing characteristics of the glass or glass coating, or both, may be determined by examining the spectraldata in the 350 - 400 nm r
9、ange. If the instrument allows spectral measurement above 700 nm, useful information on the IRtransmittance characteristics of the glass or glass coating may also be determined. If coatings are present, they are assumed toreflect and partially transmit light.4. Significance and Use4.1 Color measurem
10、ent quantifies the transmitted color for glass. The user defines an acceptable range of color appropriate forthe end use. A typical quality concern for transmittance color measurement of glass products is verification of lot-to-lot colorconsistency for end-user acceptance.1 This practice is under th
11、e jurisdiction of ASTM Committee C14 on Glass and Glass Products and is the direct responsibility of Subcommittee C14.11 on OpticalProperties.Current edition approved Jan. 1, 2008May 1, 2014. Published January 2008May 2014. Originally approved in 2008. Last previous edition approved in 2008 as C1649
12、 08. DOI: 10.1520/C1649-08.10.1520/C1649-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from
13、U.S. National Committee of the CIE (International Commission on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond St.,Salem, MA 01970, http:/www.cie-usnc.org.CIE, Commission Internationale de LEclairage, Wien, Austria, www.cie.co.at.This document is not an ASTM standard and
14、 is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only t
15、he current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 If the transmitted color of a glass product is consistent from lot-to-lot and within
16、agreed supplier-buyer acceptance criteria,the products color is expected to be consistent and acceptable for end-use.5. Apparatus5.1 For color measurements, a CIE-conforming diffuse sphere instrument capable of making transmission measurements in thetotal transmittance mode is required.5.2 In additi
17、on, a device for mounting the glass sample flush at the transmission port is required.5.3 The instrument and associated color quality software/firmware shall be capable of converting measured spectraltransmittance data to CIE L*, a* b*; Hunter L, a, b; orY, x, y values calculated for CIE illuminant
18、D65 and the CIE 1964 10 degreestandard observer. (See Practice E1164.)Any of those mappings will serve as a full numerical color descriptor. (See Practice E308.)CIE Y transmittance can also serve as an over-all indicator of transmission. For other illuminant/observer combinations, seePractice E308 f
19、or guidance in use. For effective communication of color values between sites, color measurements must beexpressed in the same color scale, illuminant, and standard observer.5.4 The expression of a color difference in terms of rectangular, polar, or elliptical color differences shall serve to quanti
20、fy thedifference between target product color and lot color. See Practice D2244.6. Materials6.1 Samples are uncoated or partially reflective coated transparent glass with defined substrate, coating compositions, andthicknesses.7. Hazards7.1 Consult Material Safety Data Sheets, and local regulations
21、for all materials used in this test method.practice.8. Color Instrument Calibration and Set up Procedure8.1 Prepare instrument for operation by following the instrument manufacturersmanufacturers instructions.8.2 Use instrument standardization to set the color instrument to the assigned values for t
22、he transmission standards supplied bythe manufacturer or other suitable reference material.8.3 To verify consistency over time in the performance of the color instrument, read and record color values of an instrumentdiagnostic standard (such as a color standard or didymium filter) at regular interva
23、ls. Care should be taken to visually inspect thesestandards for any significant visual abrasion and replace it if warranted.8.4 As the stability characteristics of coated and un-coated glass are generally good, the user may, at their option, read andrecord color values for a coated glass sample to d
24、ocument consistency in the measurement method over time. Care should be takento visually inspect the coated glass sample for any significant visual abrasion and replace it if warranted.9. Measurement Method9.1 Place the glass sample at the transmittance measurement port.9.2 At a minimum, scan the sa
25、mple over the range of wavelengths required for measurement. Two scans with a 90 rotation ofthe samples are preferable. If practical and possible, scan at least one other area of the sample as well.9.3 Correction for reflection loss of uncoated glass (optional):9.3.1 Because of historical practices,
26、 some industries apply a correction for reflection loss to the transmittance and others donot. As a result, specifications based on transmitted color measurements of glass may differ from industry segment to industrysegment. Typically, the architectural glass industry does not use the correction, bu
27、t the container glass industry does. The user ofthis document is advised to ascertain industry segment practices before deciding to apply or not apply the reflection correction.9.3.2 When required by the respective glass industry, the correction is (See Appendix X1.):Tcorrected5kTTmeasured (1)Where:
28、kT = F 2nairnglassnair21nglass2!G10. Report10.1 Report the following information:10.1.1 Sample identification,10.1.2 Color scale, illuminant, standard observer, instrument geometry and transmittance mode,C1649 14210.1.3 Sample preparation and presentation conditions, including number and pattern of
29、readings averaged, and10.1.4 Average color or color difference values, or both, relative to a product standard color to nearest hundredth of a unit.NOTE 1Sample preparation includes items of glass description such as the type and form (single layer versus multi-layer IG; laminated, pattern andthickn
30、ess), as well as the surface preparation technique (cleaning method prior to measurement, polishing).NOTE 2Sample presentation includes any side or positional information; the area of view measured in each reading; the number of readings averagedand if readings were taken in a specific pattern.10.1.
31、5 The CIE Y value may also be reported to nearest hundredths of a unit, as an instrumental measurement of the overalltransmittance of the transparent glass.11. Keywords11.1 coatings; color; glass; transmittanceAPPENDIXX1. REFLECTION LOSS CALCULATIONSX1.1 Reflection loss, R at the sample surface is d
32、etermined by the refractive indices:R5Snair2nglassnair1nglassD 2 (X1.1)X1.2 Expressed as a correction factor for transmission:kT 5 4nairnglassnair1nglass!2 512R (X1.2)X1.3 Because the glass sample has two reflecting surfaces, total reflection loss is:R 5 2R11R (X1.3)X1.4 As a result, the correction
33、factor for transmission becomes:kT 52nair nglassnair2 1nair2 512R (X1.4)X1.5 Approximate refractive indices (relative to air) for some commercial glasses:4Containers and windows (soda-lime silica) 1.52Laboratory ware (borosilicate) 1.47Other borosilicate 1.48Fiber glass (E-glass) 1.55High lead 1.54F
34、used silica 1.454 Handbook of Glass Properties, Bansal and Doremus, Editors, Chapters 1 and 2, Academic Press, 1986.C1649 143ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are ex
35、pressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revi
36、sed, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may
37、 attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United Stat
38、es. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C1649 144
