ASTM E2153-01(2011)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: E2153 − 01 (Reapproved 2011)
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
Thefundamentalprocedureforevaluatingthecolorofafluorescentspecimenistoobtainbispectral
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 establish appropriate safety and health practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This practice addresses the instrumental measurement
requirements, calibration procedures, and material standards
2. Referenced Documents
needed for obtaining precise bispectral photometric data for
computing the colors of fluorescent specimens. 2.1 ASTM Standards:
E179 Guide for Selection of Geometric Conditions for
1.2 This practice lists the parameters that must be specified
Measurement of Reflection and Transmission Properties
when bispectral photometric measurements are required in
of Materials
specific methods, practices, or specifications.
E284 Terminology of Appearance
1.3 This practice applies specifically to bispectrometers,
E925 Practice for Monitoring the Calibration of Ultraviolet-
which produce photometrically quantitative bispectral data as
Visible Spectrophotometers whose Spectral Bandwidth
output, useful for the characterization of appearance, as op-
does not Exceed 2 nm
posed to spectrofluorimeters, which produce instrument-
E958 Practice for Measuring Practical Spectral Bandwidth
dependent bispectral photometric data as output, useful for the
of Ultraviolet-Visible Spectrophotometers
purpose of chemical analysis.
E1164 PracticeforObtainingSpectrometricDataforObject-
Color Evaluation
1.4 The scope of this practice is limited to the discussion of
object-color measurement under reflection geometries; it does E1341 Practice for Obtaining Spectroradiometric Data from
Radiant Sources for Colorimetry
not include provisions for the analogous characterization of
specimens under transmission geometries. E2152 Practice for Computing the Colors of Fluorescent
Objects from Bispectral Photometric Data
1.5 This standard may involve hazardous materials,
operations, and equipment. This standard does not purport to
2.2 NPL Publications:
address all of the safety concerns, if any, associated with its NPL Report MOM 12 Problems of spectrofluorimetric stan-
use. It is the responsibility of the user of this standard to
dards for reflection and colorimetric use
1 2
This practice is under the jurisdiction of ASTM Committee E12 on Color and For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Appearance and is the direct responsibility of Subcommittee E12.05 on Fluores- contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
cence. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2011. Published November 2011. Originally the ASTM website.
approved in 2001. Last previous edition approved in 2006 as E2153 - 01 (2006). Available from National Physical Laboratory, Queens Road, Teddington,
DOI: 10.1520/E2153-01R11. Middlesex, United Kingdom TW11 0LW, http://www.npl.co.uk/.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2153 − 01 (2011)
2.3 CIE Publications: 3.2.7 discrete bispectral radiance factor, B(µ,λ), n—the
CIE No. 38 Radiometric and Photometric Characteristics of matrix defined for specified irradiation and viewing bandpass
Materials and Their Measurement functions, and viewing-wavelength sampling interval (∆λ) as
CIE No.15.2 Colorimetry, 2nd Edition follows:
CIE Report of TC-2.25: Calibration Methods and Photolu-
H
B~µ,λ![b ~µ!·∆λ (2)
λ
minescent Standards for Total Radiance Factor Measure-
ment
where:
¯
2.4 NIST Publications:
b (µ) = theaveragebispectralradiancefactorofthespecimen,
λ
NBS No. 260-66 Didymium Glass Filters for Calibrating the
as weighted by the specified irradiation and viewing
Wavelength Scale of Spectrophotometers
bandpass functions.
3.2.8 Donaldson radiance factor, D(µ,λ), n—a special case
3. Terminology
of the discrete bispectral radiance factor, for which the speci-
3.1 Definitions—The definitions contained in Terminology
fied irradiation and viewing bandpass functions are perfectly
E284 are applicable to this practice.
rectangular, with bandwidth equal to irradiation and viewing-
wavelength sampling interval.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 bispectral fluorescence radiance factor, b (µ), n—the
F
λ
NOTE 2—The Donaldson radiance factor is approximately equal to the
ratio of the spectral radiance at wavelength λ due to fluores-
ratio of the specimen radiance within the rectangular waveband of width
cence from a point on the specimen when irradiated at
∆λcenteredat λtotheradianceoftheperfectreflectingdiffuserwheneach
is irradiated over the rectangular waveband of width ∆λ centered at µ.
wavelength µ to the total radiance of the perfectly reflecting
diffuser similarly irradiated and viewed (see NPL Report
3.2.9 fluorescence, n—this standard uses the term “fluores-
MOM 12).
cence” as a general term, including both true fluorescence
-8
(with a luminescent decay time of less than 10 s) and
3.2.2 bispectral radiance factor, b (µ), n—the ratio of the
λ
phosphorescence with a delay time short enough to be indis-
spectral radiance (radiance per unit waveband) at wavelengthλ
tinguishable from fluorescence for the purpose of colorimetry.
from a point on a specimen when irradiated at wavelength µ to
the total (integrated spectral) radiance of the perfectly reflect-
3.2.10 near-diagonal element, n—off-diagonal elements of
ing diffuser similarly irradiated and viewed.
an uncorrected bispectral matrix whose values include a
significant reflection component, due to reflection overspill.
b µ [L µ /L µ (1)
~ ! ~ ! ~ !
λ λ
d
For instruments with irradiation and viewing bandpass func-
3.2.3 bispectral reflection radiance factor, b (µ), n—the
Rλ
tions which approximate the recommended trapezoidal or
ratio of the spectral radiance at wavelengthλ due to reflection
triangular shape, this should be limited to within two to three
from a point on the specimen when irradiated at wavelength µ
bands of the diagonal.
tothetotalradianceoftheperfectlyreflectingdiffusersimilarly
irradiated and viewed. 3.2.11 off-diagonal element, n—any element of a bispectral
matrix for which irradiation and viewing wavelengths are not
3.2.4 bispectrometer, n—an optical instrument equipped
equal.
with a source of irradiation, two monochromators, and a
detection system, such that a specimen can be measured at 3.2.12 reflection overspill, n—the contribution of reflection
independently-controlled irradiation and viewing wavelengths. to off-diagonal values of the discrete bispectral radiance factor
The bispectrometer is designed to allow for calibration to matrix, due to the partial overlap of irradiation and viewing
provide quantitative determination of the bispectral radiation- wavebands when nominal irradiation and viewing wavelengths
transfer properties of the specimen. (6)
are not equal (µ≠λ).
3.2.13 spectral effıciency factor, b(µ), n—the ratio of the
NOTE 1—Typically, a reference detection system monitors the radiation
incident on the specimen. This reference detection system serves to
total (integrated spectral) radiance from a point on a specimen
compensate for both temporal and spectral variations in the flux incident
when irradiated at wavelength µ to the total radiance of the
upon the specimen, by normalization of readings from the instrument’s
perfectly reflecting diffuser identically irradiated and viewed.
emission detection system.
b~µ![L~µ!/L~µ! (3)
3.2.5 diagonal elements, n—elements of a bispectral matrix d
for which irradiation and viewing wavelengths are equal.
4. Summary of Practice
3.2.6 diagonal fluorescence, n—the contribution of fluores-
4.1 Procedures are given for selecting the types and oper-
cence to diagonal values of a bispectral radiance factor matrix,
ating parameters of bispectrometers used to provide data for
due to the finite range of actual irradiation and viewing
thecalculationofCIEtristimulusvaluesandothercolorimetric
wavelengths when nominal irradiation and viewing wave-
values to quantify the colors of objects. The important steps in
lengths are equal (µ = λ).
the calibration of such instruments, and the material standards
requiredforthesesteps,aredescribed.Guidelinesaregivenfor
AvailablefromU.S.NationalCommitteeoftheCIE(InternationalCommission
the selection of specimens to obtain the highest measurement
on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
precision. Parameters are identified which must be specified
St., Salem, MA 01970, http://www.cie-usnc.org.
when bispectral photometric measurements are required in
Available from National Institute of Standards and Technology (NIST), 100
Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov. specific test methods or other documents.
E2153 − 01 (2011)
4.2 In this practice, the measuring instrument, a 6.1.5 Special requirements determined by the nature of the
bispectrometer, is equipped with two separate monochroma- specimen, such as measurement orientation for anisotropic
tors. The first, the irradiation monochromator, irradiates the specimens.
specimen with monochromatic light. The second, the viewing
monochromator, analyzes the radiation leaving the specimen.
7. Apparatus
A two-dimensional array of bispectral photometric values is
7.1 Bispectrometer—The basic instrumental requirement is
obtainedbysettingtheirradiationmonochromatorataseriesof
a bispectrometer designed for measurement of Donaldson
fixed wavelengths (µ) in the excitation band of the specimen,
radiance factor using one or more of the standard irradiation
and for each µ, using the viewing monochromator to record
and viewing geometries described in Section 8.
readings for each wavelength (λ) in the specimen’s emission
7.2 Irradiator—The irradiator, which consists of the radia-
range.Theresultingarray,onceproperlycorrected,isknownas
tion source, a dispersive element and related optical
the Donaldson matrix (2), and the value of each element (µ,λ)
components, shall irradiate the specimen with monochromatic
of this array is the Donaldson radiance factor (D(µ,λ)).
radiation of known wavelength bandpass and measurement
4.3 While recognizing the CIE recommendation (in CIE
interval.
Publication 15.2) of numerical integration at 1 nm intervals as
7.2.1 The radiation source must be stable with time and
the basic definition, this practice is limited in scope to
have adequate energy output over the wavelength range used
measurements and calculations using spectral intervals greater
for specimen irradiation.
than or equal to 5 nm.
7.2.2 The dispersive element, which provides energy in
narrow wavelength bands across the UV and visible spectral
5. Significance and Use
range, may be a prism, a grating, or one of various forms of
5.1 The bispectral or two-monochromator method is the
interference filters or wedges. The element should conform to
definitive method for the determination of the general
the following requirements:
(illuminant-independent) radiation-transfer properties of fluo-
7.2.2.1 Whenhighestmeasurementaccuracyisrequired,the
rescent specimens (2). The Donaldson radiance factor is an
wavelength range should extend from 300-830 nm; otherwise
instrument- and illuminant-independent photometric property
the range from 300 to 780 nm should suffice. For specimens
of the specimen, and can be used to calculate its color for any
confirmed to be non-fluorescent or those exhibiting only
desired illuminant and observer. The advantage of this method
visible-activated fluorescence (negligible excitation below 380
is that it provides a comprehensive characterization of the
nm), the wavelength range from 380 to 780 can be used. Each
specimen’s radiation-transfer properties, without the inaccura-
user must decide whether the loss of accuracy in the measure-
cies associated with source simulation and various methods of
ments is negligibly small for the purpose for which data are
approximation.
obtained.
7.2.2.2 The wavelength interval should be 5 or 10 nm. Use
5.2 This practice provides a procedure for selecting the
of wider wavelength intervals, such as 20 nm, may result in
operating parameters of bispectrometers used for providing
reduced accuracy. Each user must decide whether the loss of
data of the desired precision. It also provides for instrument
accuracy in the measurements is negligibly small for the
calibration by means of material standards, and for selection of
purpose for which data are obtained.
suitable specimens for obtaining precision in the measure-
7.2.2.3 The irradiation wavelength interval should equal the
ments.
viewing wavelength interval.
6. Requirements for Bispectral Photometry 7.2.2.4 The spectral bandpass (full-width at half maximum
powerinthebandofwavelengthstransmittedbythedispersive
6.1 When describing the measurement of specimens by the
element) should, for best results, be equal to the wavelength
bispectral method, the following must be specified:
interval. The spectral bandpass function should be
6.1.1 Thephotometricquantitydetermined,suchasDonald-
symmetrical, and approximately triangular or trapezoidal.
son radiance factor or spectral efficiency factor.
7.2.3 The irradiator should uniformly irradiate the sample.
6.1.2 The geometry of irradiation and viewing, including
7.3 Receiver—The receiver consists of the detector, a dis-
the following:
6.1.2.1 For bi-directional geometry, whether annular, persive element and related optical components.
circumferential, or uniplanar measurement conditions are to be
...