ASTM E991-98
(Practice)Standard Practice for Color Measurement of Fluorescent Specimens
Standard Practice for Color Measurement of Fluorescent Specimens
SCOPE
1.1 This practice describes procedures for measuring the colors of fluorescent specimens as they would be perceived when illuminated by daylight, and for calculating tristimulus values and chromaticity coordinates for these conditions.
1.2 This practice applies to the use of the one-monochromator spectrophotometer employing polychromatic illumination of the specimen and monochromatic detection of the radiant energy.
1.3 This practice can be used to provide specifications for fluorescent colors in either the 1931 or the 1964 CIE system.
1.4 This practice covers only fluorescent specimens that emit visible light. It is not intended for use with other types of luminescent materials such as phosphorescent, chemiluminescent, or electroluminescent.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E 991 – 98
Standard Practice for
Color Measurement of Fluorescent Specimens
This standard is issued under the fixed designation E991; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Thecolorsoffluorescentspecimensshouldbemeasuredunderilluminatingandviewingconditions
(spectral and geometric) that duplicate those of anticipated use. The measurement of fluorescent
specimens is more exacting than that of nonfluorescent specimens because the relative contributions
ofreflectedandfluorescedradiationwillvarywiththespectralcharacterofthesourceilluminatingthe
specimen. This places important restrictions on the instrumentation used for measurement. This
practice covers the instrumental appearance measurement of fluorescent materials using a one-
monochromator spectrophotometer.
1. Scope E308 Practice for Computing the Colors of Objects by
Using the CIE System
1.1 This practice describes procedures for measuring the
E805 PracticeforIdentificationofInstrumentalMethodsof
colors of fluorescent specimens as they would be perceived
Color or Color-Difference Measurement of Materials
when illuminated by daylight, and for calculating tristimulus
E1164 Practice for Obtaining Spectrophotometric Data for
values and chromaticity coordinates for these conditions.
Object-Color Evaluation
1.2 This practice applies to the use of one-monochromator
E1247 TestMethodforIdentifyingFluorescenceinObject-
spectrophotometer employing polychromatic illumination of
Color Specimens by Spectrophotometry
the specimen and monochromatic detection of the radiant
E1349 Test Method for Reflectance Factor and Color by
energy.
Spectrophotometry Using Bidirectional Geometry
1.3 This practice can be used to provide specifications for
E1767 Practice for Specifying the Geometry of Observa-
fluorescent colors in either the 1931 or the 1964 CIE system.
tionsandMeasurementstoCharacterizetheAppearanceof
1.4 This practice covers only fluorescent specimens that
Materials
emit visible light. It is not intended for use with other types of
2.2 CIE Standards:
luminescent materials such as phosphorescent, chemilumines-
CIE Publication No. 15.2, Colorimetry
cent, or electroluminescent.
CIE Publication No. 51, AMethod forAssessing the Qual-
1.5 This standard does not purport to address all of the
ity of Daylight Simulators for Colorimetry
safety concerns, if any, associated with its use. It is the
CIE Publication No. 76, Intercomparison on Measurement
responsibility of the user of this standard to establish appro-
of(Total)SpectralRadianceFactorofLuminescentSpeci-
priate safety and health practices and determine the applica-
mens
bility of regulatory limitations prior to use.
3. Terminology
2. Referenced Documents
3.1 ThetermsanddefinitionsinTerminologyE284applyto
2.1 ASTM Standards:
3 this practice.
E284 Terminology of Appearance
3.2 Definitions:
3.2.1 fluorescence, n—photoluminescence that ceases when
excitation ceases.
This practice is under the jurisdiction ofASTM Committee E-12 on Color and 3.2.1.1 Discussion—Fluorescence is distinguished from
Appearance and is the direct responsibility of Subcommittee E12.05 on Fluores-
phosphorescencebyatimedelaygenerallylessthan10ns.See
cence.
photoluminescence and phosphorescence.
Current edition approved June 10, 1998. Published September 1998. Originally
published as E991–84. Last previous edition E991–97.
Measurement of the fluorescent properties of materials for the purpose of
chemical analysis is not covered in this practice. The CIE documents can be obtained from USNC/CIE Publications, c/o TLA
Annual Book of ASTM Standards, Vol 06.01. Lighting Consultants, 7 Pond St., Salem MA 01970.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E991–98
3.2.2 peak spectral radiance factor, b , n—largest mea- specimen differs somewhat from that of illuminant D65 (3, 4),
peak
sured spectral radiance factor of a specimen. thecalculationanduseofcorrectedspectralradiancefactorsof
3.2.3 source conformance factor, SCF, n— the square root fluorescent materials for colorimetric purposes are not ad-
of the mean square deviation between the relative spectral dressed by this practice.
irradiance distribution curves of an instrument illuminating 4.5 When the fluorescent specimen has an angular subtense
source measured at the sample port and a specified CIE of <4° at the eye (for example, objects viewed from a distance
standard illuminant. such as a buoy at sea or a road sign on the roadway), use the
3.2.3.1 Discussion—The ultraviolet source conformance CIE 1931 (2°) standard observer. When the fluorescent speci-
factor, SCF ,iscalculatedovertherangefrom300to380nm; men has an angular subtense of >4° at the eye (for example, a
uv
the visible source conformance factor, SCF , is calculated large textile sample observed nearby), use the CIE 1964 (10°)
vis
over the range from 380 to 700 nm. supplementary standard observer.
3.2.4 ultraviolet-activated fluorescence, n— fluorescence 4.6 While the two-monochromator method (5,6,7) is con-
resultingprincipallyfromabsorptionofultravioletradiantflux, sidered the referee procedure, this one-monochromator prac-
shorter than 380 nm in wavelength. tice has found significant application for the color measure-
3.2.5 visible-activatedfluorescence,n—fluorescenceresult- ment of fluorescent specimens.
ingprincipallyfromabsorptionofvisibleradiantflux,approxi-
5. Instrument Requirements
mately 380 to 780 nm in wavelength.
5.1 The color measurement of fluorescent specimens under
4. Significance and Use
this practice requires the use of a one-monochromator spectro-
4.1 This practice describes the color measurement of fluo-
photometer meeting the following minimum criteria:
rescent specimens as they would appear when illuminated by
5.1.1 The spectrophotometer shall illuminate the specimen
CIE Illuminant D65. Since the CIE has not recommended a
withpolychromaticillumination,usuallybydirectillumination
standard source corresponding to this illuminant, this practice
from a daylight simulator.
requires that D65 be simulated within specified limits by the
5.1.2 The monochromator shall be located between the
spectral power distribution illuminating the specimen.
specimen and the detector system.
4.2 This practice applies to the instrumental color measure-
5.1.3 The wavelength measurement interval should be 10
ment of specimens exhibiting fluorescent emission within the
nmorless.SeePracticeE308andPracticeE1164forspectral
visible range. For methods to determine whether specimens
bandpass recommendations.
exhibit fluorescence, see Test Method E1247.
5.2 Requirements for CIE illuminant D65 Simulation—The
4.3 Therecommendedmeasurementgeometryforthisprac-
instrument source shall simulate CIE Illuminant D65, with a
tice is the 45/0 (or equivalent 0/45) illuminating and viewing
relative spectral irradiance distribution at the specimen port
geometry (see Practice E805 and Test Method E1349). It is
closely duplicating that of D65. Two alternative criteria are
therefereeconditionforthispractice.Theuseofhemispherical
providedtodeterminewhethertheD65simulationisadequate:
geometry is not recommended. When hemispherical geometry
5.2.1 The ultraviolet source conformance factor, SCF ,
uv
using an integrating sphere is utilized, the light emission from
over the range from 300 to 380 nm shall be less than 15.0 and
thefluorescentspecimenchangesthespectralirradianceonthe
the visible source conformance factor, SCF over the range
vis
specimen from that of the required D65 (1,2).
from 380 to 700 nm shall be less than 10.0 (seeAppendix X1
4.3.1 The use of hemispherical geometry using an integrat-
for calculation of SCF and SCF ).
uv vis
ing sphere may be permissible if it can be shown that the
1 2
l~2!
/
spectral sphere error is negligible. The spectral sphere error
SCF 5 ~S 2 S ! (1)
F ( D65 INST G
n
l 1!
~
associated with hemispherical geometry decreases as the mea-
surement area relative to the internal area of the sphere is
where:
decreased.When the spectral sphere error is negligible, results
l (1) = minimum wavelength of the range evaluated,
obtained using hemispherical geometry may for some speci-
l(2) = maximum wavelength of the range evaluated,
mens under specific measurement conditions approach those n = number of sample points,
S = relative spectral irradiance of CIE illuminant
obtained using 45/0 (0/45) geometry (2).
D65
D65, normalized to 100.0 at 560 nm, and
NOTE 1—In addition to the spectral sphere error, there are also
S = relative spectral irradiance incident on the speci-
INST
geometric differences between hemispherical geometry using an integrat-
men, determined by spectroradiometry and simi-
ing sphere and 45/0 (0/45) geometry which can affect the measurement
larly normalized to 100.0 at 560 nm.
result for highly non-Lambertian materials.
5.2.2 The D65 simulator shall have a rating not worse than
4.4 While procedures are available in the literature to
BB (CIELAB) relative to D65 as determined by the method of
correct data obtained when the spectral irradiance on the
CIE Publication No. 51.
5.2.3 In contrast to ultraviolet-activated fluorescent speci-
mens, the ultraviolet content of the illuminant does not play a
The illuminating and viewing geometry denoted by 45/0 (0/45) in this practice
is equivalent to the 45:0 (0:45) notation in Practice E1767. The use of Practice
significant role in the color measurement of visible-activated
E1767 notation is recommended for the complete description of measurement
fluorescent specimens (8). For the instrumental color measure-
geometry including aperture size, etc.
mentofvisible-activatedfluorescentspecimens,theinstrument
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
this practice. sourceshallonlyberequiredtohavea SCF lessthan10.0,or
vis
E991–98
a rating not worse than B (CIELAB) in the visible range 8.3 The accuracy with which the illuminating source simu-
relative to D65 as determined by the method of CIE Publica- lates CIE Illuminant D65 must be determined periodically by
tion No. 51. measurement of the spectral distribution of irradiance at the
5.3 The instrument must be capable of producing as output specimen port of the instrument.
spectral radiance factor as a function of wavelength over the
NOTE 3—Possiblythegreatestsinglesourceofvariabilityinfluorescent
range from 400 to 700 nm in increments of 10 nm or less.The
color measurement is differences between the spectral distribution of the
preferred range is from 380 to 780 nm.
source illuminating the specimen at the sample port and the specified CIE
5.4 For geometrically sensitive fluorescent specimens, the illuminant.
illuminating and viewing geometry shall consist of direct
9. Report
specimen irradiation by the illuminator system at an angle of
45 62°fromthenormal,withanapertureanglenotexceeding 9.1 Report the following information (see Practices E805
and E1164):
4°, and viewing at an angle of 0 6 2° (along the normal) with
an aperture angle not exceeding 4° (the combination denoted 9.1.1 Specimen Description—Include the following:
9.1.1.1 Specimen identification and type, for example
by 45/0) (9) or the equivalent 0/45 geometry.
whether the sample is opaque, translucent or transparent, a
5.4.1 For specimens known to be relatively insensitive to
measurementgeometry,theilluminatingandviewinggeometry textile or plastic, retroreflective, ultraviolet-activated or
visible-activated.
shouldconsistofdirectspecimenirradiationbytheilluminator
systematanangleof45 62°fromthenormaltothespecimen 9.1.1.2 Specimen Substrate—The instrumental color mea-
surement of specimens that are not opaque can be influenced
surface. The angle between the direction of viewing and the
normal to the specimen surface should not exceed 10°. The by the spectral reflectance of the material behind the specimen
(10). Specimens are typically measured mounted on the sub-
angle between the axis and any ray of an illuminating beam
should not exceed 8°. The same restriction applies to the strate upon which they are to used.
9.1.2 Instrument Parameters—Including the following:
viewing beam. The equivalent 0/45° geometry is allowed (see
Practice E1164). 9.1.2.1 Measurement Conditions—Indicate whether annu-
lar, circumferential, or uniplanar measurement conditions.
6. Procedure
9.1.2.2 The spectral parameters, including the wavelength
6.1 OperatethespectrophotometerinaccordancewithPrac-
range, wavelength measurement interval, and spectral band-
tice E1164 and Test Method E1349. This includes mandatory
pass.
standardization of the following:
9.1.2.3 The adequacy of the D65 simulation of the instru-
6.1.1 Zero setting of the reflectance scale,
ment source at the sample port as determined in 5.2 of this
6.1.2 Full-scale value of the reflectance scale of the instru-
practiceintermsof SCF,orCIELABratinginaccordancewith
ment by use of the white standard. Follow the instrument
the method of Publication CIE No. 51.
manufacturer’s instructions.
9.2 Measurement Results:
6.2 Express spectral radiances obtained as radiance factors
9.2.1 The CIE tristimulus values (X, Y, Z) or chromaticity
relative to the perfect reflecting diffuser assigned a value of
coordinates (x, y, Y) for CIE Illuminant D65 for either the CIE
1.000 (100.0%) at each wavelength. 1931 (2°) standard observer or the CIE 1964 (10°) supplemen-
tary standard observer.
7. Calculation
9.2.2 The wavelength of peak spectral radiance factor from
7.1 Calculate CIE tristimulus values and chromaticity coor-
the measured spectral radiance factors obtained.
dinates for CIE Illuminant D65 and either the CIE 1931 (2°)
standard observer or the CIE 1964 (10°) supplementary stan-
10. Precision and Bias
dard observer (see Practice E308).
10.1 Theprecisionandbiasoftheprocedureinthispractice
is being determined.
8. Standardization and Verification
10.2 In the interim, the following assessment of repeatabil-
8.1 Standardization of zero and full-scale values is required
ity and reproducibility is provided for illustrative purposes.
at the time of measurement.
These results are based on experiments that tested the entire
8.2 System Verification (see Practice E1164, Section 9):
procedureforthecolormeasurementoffluorescentspecimens,
8.2.1 Verify the calibration of the wavelength scale (recom-
including the calculation of spectral radiance factors corrected
mended).
8.2.2 The precision and bias of the entire measurement
system, including
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.