ASTM E2153-01(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E2153–01(Reapproved2006)
Standard Practice for
Obtaining Bispectral Photometric Data for Evaluation of
Fluorescent Color
This standard is issued under the fixed designation E2153; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The fundamental procedure for evaluating the color of a fluorescent specimen is to obtain bispectral
photometric data for specified irradiating and viewing geometries, and from these data to compute
tristimulus values based on a CIE (International Commission on Illumination) standard observer and
a CIE standard illuminant. The considerations involved and the procedures used to obtain precise
bispectral photometric data are contained in this practice. Values and procedures for computing CIE
tristimulus values from bispectral photometric data are contained in Practice E2152. General
considerations regarding the selection of appropriate irradiating and viewing geometries are contained
inGuideE179;furtherspecificconsiderationsapplicabletofluorescentspecimensarecontainedinthis
practice.
1. Scope use. It is the responsibility of the user of this standard to
establish appropriate safety and health practices and deter-
1.1 This practice addresses the instrumental measurement
mine the applicability of regulatory limitations prior to use.
requirements, calibration procedures, and material standards
needed for obtaining precise bispectral photometric data for
2. Referenced Documents
computing the colors of fluorescent specimens.
2.1 ASTM Standards:
1.2 This practice lists the parameters that must be specified
E179 Guide for Selection of Geometric Conditions for
when bispectral photometric measurements are required in
Measurement of Reflection andTransmission Properties of
specific methods, practices, or specifications.
Materials
1.3 This practice applies specifically to bispectrometers,
E284 Terminology of Appearance
which produce photometrically quantitative bispectral data as
E925 PracticeforMonitoringtheCalibrationofUltraviolet-
output, useful for the characterization of appearance, as op-
Visible Spectrophotometers whose Spectral Slit Width
posed to spectrofluorimeters, which produce instrument-
does not Exceed 2 nm
dependent bispectral photometric data as output, useful for the
E958 Practice for Measuring Practical Spectral Bandwidth
purpose of chemical analysis.
of Ultraviolet-Visible Spectrophotometers
1.4 The scope of this practice is limited to the discussion of
E1164 Practice for Obtaining Spectrometric Data for
object-color measurement under reflection geometries; it does
Object-Color Evaluation
not include provisions for the analogous characterization of
E1341 PracticeforObtainingSpectroradiometricDatafrom
specimens under transmission geometries.
Radiant Sources for Colorimetry
1.5 This standard may involve hazardous materials, opera-
E2152 Practice for Computing the Colors of Fluorescent
tions, and equipment. This standard does not purport to
Objects from Bispectral Photometric Data
address all of the safety concerns, if any, associated with its
2.2 NPL Publications:
This practice is under the jurisdiction of ASTM Committee E12 on Color and
Appearance and is the direct responsibility of Subcommittee E12.05 on Fluores-
cence. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2006. Published December 2006. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2001. Last previous edition approved in 2001 as E2153 - 01. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E2153-01R06. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2153–01 (2006)
NPLReport MOM 12 Problems of spectrofluorimetric stan- due to the finite range of actual irradiation and viewing
dards for reflection and colorimetric use wavelengths when nominal irradiation and viewing wave-
2.3 CIE Publications: lengths are equal (µ = l).
CIE No. 38 Radiometric and Photometric Characteristics of 3.2.7 discrete bispectral radiance factor, B(µ,l), n—the
Materials and Their Measurement matrix defined for specified irradiation and viewing bandpass
CIE No.15.2 Colorimetry, 2nd Edition functions, and viewing-wavelength sampling interval (Dl) as
CIE Report of TC-2.25: Calibration Methods and Photolu- follows:
minescent Standards for Total Radiance Factor Measure-
–
4 B~µ,l! [ b ~µ!· Dl (2)
l
ment
2.4 NIST Publications:
where:
NBS No. 260-66 Didymium Glass Filters for Calibrating
–
= the average bispectral radiance factor of the speci-
b (µ)
5 l
the Wavelength Scale of Spectrophotometers
men, as weighted by the specified irradiation and
viewing bandpass functions.
3. Terminology
3.2.8 Donaldson radiance factor, D(µ,l), n—a special case
3.1 Definitions—The definitions contained in Terminology
of the discrete bispectral radiance factor, for which the speci-
E284 are applicable to this practice.
fied irradiation and viewing bandpass functions are perfectly
3.2 Definitions of Terms Specific to This Standard:
rectangular, with bandwidth equal to irradiation and viewing-
3.2.1 bispectral fluorescence radiance factor, b (µ), n—the
wavelength sampling interval.
F
l
ratio of the spectral radiance at wavelength l due to fluores-
NOTE 2—The Donaldson radiance factor is approximately equal to the
cence from a point on the specimen when irradiated at
ratio of the specimen radiance within the rectangular waveband of width
wavelength µ to the total radiance of the perfectly reflecting
Dl centered at l to the radiance of the perfect reflecting diffuser when
diffuser similarly irradiated and viewed (see NPL Report
each is irradiated over the rectangular waveband of width Dl centered at
MOM 12). µ.
3.2.2 bispectral radiance factor, b (µ) , n—the ratio of the
l
3.2.9 fluorescence, n—this standard uses the term “fluores-
spectralradiance(radianceperunitwaveband)atwavelength l
cence” as a general term, including both true fluorescence
-8
from a point on a specimen when irradiated at wavelength µ to
(with a luminescent decay time of less than 10 s) and
the total (integrated spectral) radiance of the perfectly reflect-
phosphorescence with a delay time short enough to be indis-
ing diffuser similarly irradiated and viewed.
tinguishable from fluorescence for the purpose of colorimetry.
b ~µ! [ L ~µ!/L~µ! (1) 3.2.10 near-diagonal element, n—off-diagonal elements of
l l d
an uncorrected bispectral matrix whose values include a
3.2.3 bispectral reflection radiance factor, b (µ) , n—the
Rl
significant reflection component, due to reflection overspill.
ratio of the spectral radiance at wavelength l due to reflection
For instruments with irradiation and viewing bandpass func-
from a point on the specimen when irradiated at wavelength µ
tions which approximate the recommended trapezoidal or
tothetotalradianceoftheperfectlyreflectingdiffusersimilarly
triangular shape, this should be limited to within two to three
irradiated and viewed.
bands of the diagonal.
3.2.4 bispectrometer, n—an optical instrument equipped
3.2.11 off-diagonal element, n—any element of a bispectral
with a source of irradiation, two monochromators, and a
matrix for which irradiation and viewing wavelengths are not
detection system, such that a specimen can be measured at
equal.
independently-controlled irradiation and viewing wavelengths.
3.2.12 reflection overspill, n—the contribution of reflection
The bispectrometer is designed to allow for calibration to
to off-diagonal values of the discrete bispectral radiance factor
provide quantitative determination of the bispectral radiation-
matrix, due to the partial overlap of irradiation and viewing
transfer properties of the specimen. (6)
wavebands when nominal irradiation and viewing wavelengths
NOTE 1—Typically, a reference detection system monitors the radiation
are not equal (µfil).
incident on the specimen. This reference detection system serves to
3.2.13 spectral effıciency factor, b(µ), n—the ratio of the
compensate for both temporal and spectral variations in the flux incident
total (integrated spectral) radiance from a point on a specimen
upon the specimen, by normalization of readings from the instrument’s
when irradiated at wavelength µ to the total radiance of the
emission detection system.
perfectly reflecting diffuser identically irradiated and viewed.
3.2.5 diagonal elements, n—elements of a bispectral matrix
b~µ! [ L~µ!/L~µ! (3)
d
for which irradiation and viewing wavelengths are equal.
3.2.6 diagonal fluorescence, n—the contribution of fluores-
4. Summary of Practice
cence to diagonal values of a bispectral radiance factor matrix,
4.1 Procedures are given for selecting the types and oper-
ating parameters of bispectrometers used to provide data for
3 thecalculationofCIEtristimulusvaluesandothercolorimetric
Available from National Physical Laboratory, Queens Road, Teddington,
values to quantify the colors of objects. The important steps in
Middlesex, United Kingdom TW11 0LW, http://www.npl.co.uk/.
AvailablefromU.S.NationalCommitteeoftheCIE(InternationalCommission
the calibration of such instruments, and the material standards
on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
requiredforthesesteps,aredescribed.Guidelinesaregivenfor
St., Salem, MA 01970, http://www.cie-usnc.org.
the selection of specimens to obtain the highest measurement
Available from National Institute of Standards and Technology (NIST), 100
Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov. precision. Parameters are identified which must be specified
E2153–01 (2006)
when bispectral photometric measurements are required in 6.1.5 Special requirements determined by the nature of the
specific test methods or other documents. specimen, such as measurement orientation for anisotropic
4.2 Inthispractice,themeasuringinstrument,abispectrom- specimens.
eter, is equipped with two separate monochromators. The first,
the irradiation monochromator, irradiates the specimen with
7. Apparatus
monochromatic light. The second, the viewing monochroma-
7.1 Bispectrometer—The basic instrumental requirement is
tor, analyzes the radiation leaving the specimen. A two-
a bispectrometer designed for measurement of Donaldson
dimensional array of bispectral photometric values is obtained
radiance factor using one or more of the standard irradiation
by setting the irradiation monochromator at a series of fixed
and viewing geometries described in Section 8.
wavelengths (µ) in the excitation band of the specimen, and for
7.2 Irradiator—The irradiator, which consists of the radia-
each µ, using the viewing monochromator to record readings
tion source, a dispersive element and related optical compo-
for each wavelength (l) in the specimen’s emission range.The
nents, shall irradiate the specimen with monochromatic radia-
resulting array, once properly corrected, is known as the
tion of known wavelength bandpass and measurement interval.
Donaldson matrix (2), and the value of each element (µ,l) of
7.2.1 The radiation source must be stable with time and
this array is the Donaldson radiance factor (D(µ,l)).
have adequate energy output over the wavelength range used
4.3 While recognizing the CIE recommendation (in CIE
for specimen irradiation.
Publication 15.2) of numerical integration at 1 nm intervals as
7.2.2 The dispersive element, which provides energy in
the basic definition, this practice is limited in scope to
narrow wavelength bands across the UV and visible spectral
measurements and calculations using spectral intervals greater
range, may be a prism, a grating, or one of various forms of
than or equal to 5 nm.
interference filters or wedges. The element should conform to
the following requirements:
5. Significance and Use
7.2.2.1 Whenhighestmeasurementaccuracyisrequired,the
5.1 The bispectral or two-monochromator method is the
wavelength range should extend from 300-830 nm; otherwise
definitive method for the determination of the general
the range from 300 to 780 nm should suffice. For specimens
(illuminant-independent) radiation-transfer properties of fluo-
confirmed to be non-fluorescent or those exhibiting only
rescent specimens (2). The Donaldson radiance factor is an
visible-activated fluorescence (negligible excitation below 380
instrument- and illuminant-independent photometric property
nm), the wavelength range from 380 to 780 can be used. Each
of the specimen, and can be used to calculate its color for any
user must decide whether the loss of accuracy in the measure-
desired illuminant and observer. The advantage of this method
ments is negligibly small for the purpose for which data are
is that it provides a comprehensive characterization of the
obtained.
specimen’s radiation-transfer properties, without the inaccura-
7.2.2.2 The wavelength interval should be 5 or 10 nm. Use
cies associated with source simulation and various methods of
of wider wavelength intervals, such as 20 nm, may result in
approximation.
reduced accuracy. Each user must decide whether the loss of
5.2 This practice provides a procedure for selecting the
accuracy in the measurements is negligibly small for the
operating parameters of bispectrometers used for providing
purpose for which data are obtained.
data of the desired precision. It also provides for instrument
7.2.2.3 The irradiation wavelength interval should equal the
calibration by means of material standards, and for selection of
viewing wavelength interval.
suitable specimens for obtaining precision in the measure-
7.2.2.4 The spectral bandpass (full-width at half maximum
ments.
powerinthebandofwavelengthstransmittedbythedispersive
6. Requirements for Bispectral Photometry element) should, for best results, be equal to the wavelength
interval. The spectral bandpass function should be symmetri-
6.1 When describing the measurement of specimens by the
cal, and approximately triangular or trapezoidal.
bispectral method, the following must be specified:
7.2.3 The irradiator should uniformly irradiate the sample.
6.1.1 Thephotometricquantitydetermined,suchasDonald-
7.3 Receiver—The receiver consists of the detector, a dis-
son radiance factor or spectral efficiency factor.
persive element and related optical components.
6.1.2 The geometry of irradiation and viewing, including
7.3.1 The detector must be a suitable photodetector such as
the following:
a photoelectric device or s
...