ASTM E2630-2008 Standard Test Method for Luminance Ratio of a Fluorescent Specimen using a Narrow Band Source.pdf

1、Designation: E 2630 08Standard Test Method forLuminance Ratio of a Fluorescent Specimen using a NarrowBand Source1This standard is issued under the fixed designation E 2630; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year

2、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 test method covers the instrumental measurementof the luminance ratio of a fluorescent coating or sheet sample

3、when illuminated by a narrow band source.1.2 This test method is generally applicable to any coatingor sheeting material having combined fluorescent and reflectiveproperties, where the fluorescence is activated by 405 nm light.1.3 This test method is intended as a companion to Speci-fication E 2501

4、to support the development and specification ofindustrial coatings that are used in a system for detection ofcoating defects when inspected with the Specification E 2501light source. This test method establishes a quantitative mea-sure of the optical property of a coating that correlates to itsabili

5、ty to enhance defect contrast under the specified inspectionlight source.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its us

6、e. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2805 Test Method for Hiding Power of Paints by Reflec-tometryD 4356 Pract

7、ice for Establishing Consistent Test MethodTolerances3D 5162 Practice for Discontinuity (Holiday) Testing ofNonconductive Protective Coating on Metallic SubstratesE 179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Properties ofMaterialsE 284 Terminology o

8、f AppearanceE 1164 Practice for Obtaining Spectrometric Data forObject-Color EvaluationE 1488 Guide for Statistical Procedures to Use in Develop-ing and Applying Test MethodsE 2501 Specification for Light Source Products for Inspec-tion of Fluorescent Coatings2.2 Other Documents:ISO 10527:2007(E)/CI

9、E S 014-1/E:2006 CIE StandardColorimetric Observers4CIE Publication 69:1987 Methods of characterizing illumi-nance meters and luminance meters: Performance, char-acteristics and specificaitons42.3 SSPC:SSPC-SP 10/NACE No. 2 Near-White Blast Cleaning53. Terminology3.1 The definitions contained in Gui

10、de E 179, TerminologyE 284, and Practice E 1164 are applicable to this test method.3.2 The definitions for coating defects, discontinuity, holi-day, and pinhole are contained in Practice D 5162.3.3 Definitions of Terms Specific to This Standard:3.3.1 luminance ration, nluminance of the sample under

11、agiven narrow band 405 nm source divided by the luminance ofa 25 % reflecting Lambertian diffuser under the same narrowband 405 nm source.4. Summary of Test Method4.1 This test method provides a procedure for measuring theluminance ratio of a fluorescent, reflective coating compared toa 25 % reflect

12、ing Lambertian diffuser, which is similar to steelgrit blasted to an SSPC-SP 10/NACE No. 2 near-white metalblast.1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.05 onFluorescence.Current edition approved Ju

13、ne 1, 2008. Published July 2008.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from U.

14、S. National Committee of the CIE (International Commissionon Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 PondSt., Salem, MA 01970, http:/www.cie-usnc.org.5Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor,Pittsburgh, PA 15222-4656, http:/www.ssp

15、c.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 This test method requires the use of a luminance meter,a narrow band 405 nm source and a calibrated non-fluorescentreflectance standard.5. Significance and Use5.1 The test met

16、hod is suitable for the development, speci-fication and quality control testing of fluorescent and non-fluorescent coatings that are intended to be inspected fordefects under Specification E 2501 illumination.6. Apparatus6.1 Illuminator:6.1.1 The source shall have a peak wavelength of 405 nm(61 nm),

17、 a symmetric unimodal distribution with a full widthhalf maximum of 16 nm (62 nm). The shape of the spectraldistribution shall be triangular, Gaussian or isosceles trapezoi-dal where the width of the peak shall be less than one sixth thesize of the base.NOTE 1A uniform or rectangular distribution do

18、es not meet thiscondition.NOTE 2An informational appendix (Appendix X1) is provided thatbriefly summarizes the reasons for the choices of tolerances in this testmethod.6.1.2 The integrated irradiance over the wavelength range490 to 760 nm shall be less than 0.01 % of the integratedirradiance over th

19、e wavelength range 380 to 760 nm.NOTE 3The light from 490 to 760 nm is typically from fluorescencegenerated in the light source. This light is heavily weighted by theluminous efficacy function, V(l), resulting in large errors in the luminanceratio measurement. The fluorescence can be eliminated with

20、 a blue-greencolored glass filter that has an internal transmittance at a referencethickness of 1 mm greater than 0.90 at 405 nm and less than 0.05 acrossthe wavelength range of 500 to 680 nm.6.1.3 The source shall produce a minimum irradiance suf-ficient to ensure a signal-to-noise ratio of 100 to

21、1 for theluminance meter described in 6.2.NOTE 4An irradiance of 10 W/m2is typically sufficient.6.1.4 The illuminated area shall be at least twice the viewingarea of the luminance meter. The minimum viewing area isspecified in 6.2.4.6.1.5 The source irradiance shall be stable to 1 % over thetime fra

22、me of the measurements.6.1.6 The illuminance on the sample surface shall be uni-form within 65 % of the average illuminance normal to thesource. The illuminator may be collimated or not.6.2 Luminance Meter:6.2.1 The responsivity and range of the luminance metershall be sufficient so that readings of

23、 both the non-fluorescentreflectance standard and the fluorescent sample are measuredwith a resolution of at least 1 part in 100.6.2.2 If the luminance meter is filter based, the spectralresponsivity of the luminance meter shall match that of the1931 CIE Standard Photopic Observer. (ISO 10527:2007(E

24、)/CIE S 014-1/E:2006) The individual spectral mismatch correc-tion factors or the ratio of spectral mismatch correction factorswith respect to the illuminator described in 6.1 shall bedetermined for the luminance meter to at least 1 part in 100when measuring the non-fluorescent reflectance standard

25、andthe fluorescent sample.NOTE 5The ratio of the spectral mismatch correction factors may bedetermined by using a non-fluorescent reflectance standard calibratedunder the source described in 6.1 and a fluorescent sample similar to thetest sample, which are calibrated for luminance ratio under the so

26、urcedescribed in 6.1.NOTE 6An informational appendix (Appendix X1) is provided thatbriefly summarizes the method for calculating the spectral mismatchcorrection factors or the ratio of such.6.2.3 If the luminance meter is spectrally based, the out-of-band stray light rejection shall be better than 1

27、 310-5.6.2.4 The field-of-view of the luminance meter and thedistance from the sample surface shall be such that the viewedregion shall be larger than 2.5 cm2with no dimension smallerthan 1.3 cm.NOTE 7The viewing area of the luminance meter depends on the fieldof view and the distance from the sampl

28、e. The viewing area for a circularaperture is calculated by using the following equation:viewing area 5 tanv /2! d!2 p / cos45! (1)where:v = field of view of the luminance meter andd = distance between the luminance meter and the test sample.6.2.5 The luminance meter shall be insensitive to thepolar

29、ization of the light.6.2.6 The linearity of the luminance meter over the range ofmeasurements shall be within 1 %. Correction factors may beused to ensure a linear response.6.2.7 The stability of the luminance meter over the durationof the measurements shall not vary more than 1 %.6.2.8 The out-of-v

30、iew sensitivity, described in CIE Publica-tion 69, of the luminance meter shall be less than 0.5 %.6.3 Non-fluorescent Reflectance Standard:6.3.1 The non-fluorescent reflectance standard shall be cali-brated in a 0:45 geometry for luminous reflectance under thesource described in 6.1with an expanded

31、 uncertainty (k =2)ofless than 1 %.NOTE 8The magnitude of the luminous reflectance of the non-fluorescent reflectance standard is somewhat arbitrary, because it isnormalized to 0.25 in the calculations shown in 10.1. Typically, themagnitude of the luminous reflectance of the non-fluorescent reflecta

32、ncestandard is above 0.9 in order to have a larger signal-to-noise ratio.6.3.2 The non-fluorescent reflectance standard shall have anintegrated radiance over the wavelength range 490 to 760 nmless than 0.05 % of the integrated radiance over the wavelengthrange 380 to 760 nm under the illuminator spe

33、cified in 6.1.6.3.3 The non-fluorescent reflectance standard shall producea diffuse distribution when illuminated.7. Test Specimen7.1 Prepare coating in accordance with Test Method D 2805for drawdown sample for hiding power by reflectometry.7.2 Alternately, prepare by spraying or drawing down on abl

34、ack substrate that has a maximum reflectance of 1 % anddoes not fluoresce.7.3 The coating dry film thickness shall be within themanufacturers recommended range for the intended applica-tion.E26300828. Calibration and Standardization8.1 The luminance meter shall be calibrated according to themanufact

35、urers specification. The individual spectral mismatchcorrection factors or the ratio of spectral mismatch correctionfactors with respect to the illuminator described in 6.1 shall bedetermined for the luminance meter when measuring thenon-fluorescent reflectance standard and the fluorescent sampleto

36、at least 1 part in 100. (See Note 5.)8.2 The non-fluorescent reflectance standard shall be cali-brated as described in 6.3.1.9. Procedure9.1 Fig. 1 provides a schematic for the measurement align-ment. The measurements shall be conducted in the dark suchthat the signal measured in 9.5 is less than 1

37、part of the signalmeasured in 9.4.9.2 Position the illuminator described in 6.1 such that theangle between the direction of illumination and the normal tothe specimen surface shall not exceed 2. Position the lumi-nance meter such that the angle between the direction ofviewing and the normal to the s

38、pecimen surface shall be 45 62.NOTE 9Fluorescent coatings inspected under a 405 nm illuminatorenhance defect detection through two mechanisms: (1) enhanced contrastbetween the fluorescent coating and nonfluorescent substrate; and (2)uniform coating color and brightness regardless of the viewing angl

39、e. Thesecond mechanism is important for inspecting the fluorescent coatingalong welds, in corners and on edges. Under white light inspection,defects in these areas are obscured by glare and shadows. With a 405 nminspection light, dark spots are unambiguously interpreted as defects. Thiseffect is pri

40、marily responsible for the increased productivity and accuracyreported by coatings inspectors in field trials. The luminance ratio at a 45viewing angle correlates with this property better than that at a smallerviewing angle.9.3 The distance between the luminance meter and thesample surface shall be

41、 set such that the field-of-view definesa region of interest that is over illuminated by the illuminatoraccording to 6.1.4.9.4 Measure the non-fluorescent reflectance standard withthe luminance meter.9.4.1 Handle the samples carefully; avoid scratching ortouching the area to be measured. To remove d

42、ust and lint usedry, filtered, pressurized nitrogen.9.5 Block the illuminator such that the non-fluorescentreflectance standard is not illuminated and measure the darknon-fluorescent reflectance standard signal.9.6 Position the fluorescent sample and measure the fluo-rescent sample with the luminanc

43、e meter.9.7 Block the illuminator such that the fluorescent sample isnot illuminated and measure the dark fluorescent samplesignal.9.8 Calculate the luminance ration using Eq 2 specified in10.110. Calculation10.1 For each fluorescent sample calculate the luminanceratio using the following equation:R

44、LB5s sd!sP sP,d!FPFrB0.25(2)where:RLB= luminance ratio,s = luminance signal for the fluorescent sample,sd= dark luminance signal for the fluorescent sample,sP= luminance signal for the non-fluorescent reflectancestandard,sP,d= dark luminance signal for the non-fluorescent re-flectance standard,F = s

45、pectral mismatch correction factor for the fluores-cent sample under the illuminator,FP= spectral mismatch correction factor for the non-fluorescent reflectance standard under the illumina-tor, andrB= luminous reflectance of the non-fluorescent reflec-tance standard under the illuminator.11. Report1

46、1.1 The report shall contain the following information.11.2 Sample identification including any commercial desig-nation and manufacturer lot number.11.3 Date of measurement.11.4 Identification of the luminous reflectance of the non-fluorescent reflectance standard.11.5 Description of apparatus.11.5.

47、1 Peak wavelength and full width half maximum of theilluminator.11.5.2 Make and model number of luminance meter.11.5.3 Distance between luminance meter and test speci-men.11.5.4 Filed-of-view of the luminance meter.11.6 The luminance ratio.FIG. 1 A Schematic of the Measurement AlignmentE263008312. P

48、recision and Bias12.1 PrecisionThe repeatability and the reproducibility ofthis test method is being determined and will be available on orbefore January 2011.12.2 A preliminary estimate of precision has been madebased on a test method sensitivity analysis. The repeatabilitystandard deviation is exp

49、ected to be less than 1.2 %. Thereproducibility standard deviation is expected to be less than13.5 %. These expectations are based on analysis of variabilityand ruggedness testing. The tolerance propagation equationfrom Practice D 4356 was followed.12.3 BiasThe bias of this test method is being determinedand will be available on or before January 2011.13. Measurement Uncertainty13.1 The measurement uncertainty analysis shall provide astatement concerning each of the following components.13.2 Signal resolution.13.3 Spectral mismatch correction factor (