ASTM E2153-01
(Practice)Standard Practice for Obtaining Bispectral Photometric Data for Evaluation of Fluorescent Color
Standard Practice for Obtaining Bispectral Photometric Data for Evaluation of Fluorescent Color
SCOPE
1.1 This practice addresses the instrumental measurement requirements, calibration procedures, and material standards needed for obtaining precise bispectral photometric data for computing the colors of fluorescent specimens.
1.2 This practice lists the parameters that must be specified when bispectral photometric measurements are required in specific methods, practices, or specifications.
1.3 This practice applies specifically to bispectrometers, which produce photometrically quantitative bispectral data as output, useful for the characterization of appearance, as opposed to spectrofluorimeters, which produce instrument-dependent bispectral photometric data as output, useful for the purpose of chemical analysis.
1.4 The scope of this practice is limited to the discussion of object-color measurement under reflection geometries; it does not include provisions for the analogous characterization of specimens under transmission geometries.
1.5 This standard may involve hazardous materials, operations, and equipment. 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.
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:E2153–01
Standard Practice for
Obtaining Bispectral Photometric Data for Evaluation of
Fluorescent Color
This standard is issued under the fixed designation E 2153; 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 (e) 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 E 2152. General
considerations regarding the selection of appropriate irradiating and viewing geometries are contained
in Guide E 179; further specific considerations applicable to fluorescent specimens are contained in
this practice.
1. Scope 2. Referenced Documents
1.1 This practice addresses the instrumental measurement 2.1 ASTM Standards:
requirements, calibration procedures, and material standards E 179 Guide for Selection of Geometric Conditions for
needed for obtaining precise bispectral photometric data for Measurement of Reflection andTransmission Properties of
computing the colors of fluorescent specimens. Materials
1.2 This practice lists the parameters that must be specified E 284 Terminology of Appearance
when bispectral photometric measurements are required in E 925 PracticeforthePeriodicCalibrationofNarrowBand-
specific methods, practices, or specifications. Pass Spectrophotometers
1.3 This practice applies specifically to bispectrometers, E 958 Practice for Measuring Practical Spectral Bandwidth
which produce photometrically quantitative bispectral data as of Ultraviolet-Visible Spectrophotometers
output, useful for the characterization of appearance, as op- E 1164 Practice for Obtaining Spectrophotometric Data for
posed to spectrofluorimeters, which produce instrument- Object-Color Evaluation
dependent bispectral photometric data as output, useful for the E 1341 Practice for Obtaining Spectroradiometric Data
purpose of chemical analysis. from Radiant Sources for Colorimetry
1.4 The scope of this practice is limited to the discussion of E 2152 Practice for Computing the Colors of Fluorescent
object-color measurement under reflection geometries; it does Objects from Bispectral Photometric Data
not include provisions for the analogous characterization of 2.2 NPL Publications:
specimens under transmission geometries. NPLReport MOM 12 Problems of spectrofluorimetric stan-
1.5 This standard may involve hazardous materials, opera- dards for reflection and colorimetric use
tions, and equipment. This standard does not purport to 2.3 CIE Publications:
address all of the safety concerns, if any, associated with its CIE No. 38 Radiometric and Photometric Characteristics of
use. It is the responsibility of the user of this standard to Materials and Their Measurement
establish appropriate safety and health practices and deter-
mine the applicability of regulatory limitations prior to use.
Annual Book of ASTM Standards, Vol 06.01.
Annual Book of ASTM Standards, Vol 03.06.
1 4
This practice is under the jurisdiction of ASTM Committee E12 on Color and Available from National Physical Laboratory, Queens Road, Teddington,
Appearance and is the direct responsibility of Subcommittee E12.05 on Fluores- Middlesex, United Kingdom TW11 0LW.
cence. AvailablefromUSNC/CIEPublicationsOffice,TLA-LightingConsultants,Inc,
Current edition approved June 10, 2001. Published August 2001. 7 Pond St., Salem, MA 01970–4819.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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.
E2153–01
CIE No.15.2 Colorimetry, 2nd Edition
where:
CIE Report of TC-2.25: Calibration Methods and Photolu- –
= the average bispectral radiance factor of the speci-
b (µ)
l
minescent Standards for Total Radiance Factor Measure-
men, as weighted by the specified irradiation and
ment
viewing bandpass functions.
2.4 NIST Publications:
3.2.8 Donaldson radiance factor, D(µ,l)—a special case of
NBS No. 260-66 Didymium Glass Filters for Calibrating
the discrete bispectral radiance factor, for which the specified
the Wavelength Scale of Spectrophotometers
irradiation and viewing bandpass functions are perfectly rect-
angular, with bandwidth equal to irradiation and viewing-
3. Terminology
wavelength sampling interval.
3.1 Definitions—The definitions contained in Terminology
NOTE 2—The Donaldson radiance factor is approximately equal to the
E 284 are applicable to this practice.
ratio of the specimen radiance within the rectangular waveband of width
3.2 Definitions of Terms Specific to This Standard:
Dl centered at l to the radiance of the perfect reflecting diffuser when
3.2.1 bispectral fluorescence radiance factor, b (µ)—the each is irradiated over the rectangular waveband of width Dl centered at
F
l
µ.
ratio of the spectral radiance at wavelength l due to fluores-
cence from a point on the specimen when irradiated at
3.2.9 fluorescence—this standard uses the term “fluores-
wavelength µ to the total radiance of the perfectly reflecting
cence” as a general term, including both true fluorescence
-8
diffuser similarly irradiated and viewed (see NPL Report
(with a luminescent decay time of less than 10 s) and
MOM 12).
phosphorescence with a delay time short enough to be indis-
3.2.2 bispectral radiance factor, b (µ) —the ratio of the
l tinguishable from fluorescence for the purpose of colorimetry.
spectralradiance(radianceperunitwaveband)atwavelength l
3.2.10 near-diagonal element—off-diagonal elements of an
from a point on a specimen when irradiated at wavelength µ to
uncorrected bispectral matrix whose values include a signifi-
the total (integrated spectral) radiance of the perfectly reflect-
cant reflection component, due to reflection overspill. For
ing diffuser similarly irradiated and viewed.
instruments with irradiation and viewing bandpass functions
which approximate the recommended trapezoidal or triangular
b ~µ! [ L ~µ!/L~µ! (1)
l l d
shape,thisshouldbelimitedtowithintwotothreebandsofthe
3.2.3 bispectralreflectionradiancefactor,b (µ)—theratio
Rl
diagonal.
of the spectral radiance at wavelength l due to reflection from
3.2.11 off-diagonal element—any element of a bispectral
a point on the specimen when irradiated at wavelength µ to the
matrix for which irradiation and viewing wavelengths are not
total radiance of the perfectly reflecting diffuser similarly
equal.
irradiated and viewed.
3.2.12 reflection overspill—the contribution of reflection to
3.2.4 bispectrometer—an optical instrument equipped with
off-diagonal values of the discrete bispectral radiance factor
a source of irradiation, two monochromators, and a detection
matrix, due to the partial overlap of irradiation and viewing
system, such that a specimen can be measured at
wavebands when nominal irradiation and viewing wavelengths
independently-controlled irradiation and viewing wavelengths.
are not equal (µfil).
The bispectrometer is designed to allow for calibration to
3.2.13 spectral effıciency factor, b(µ)—the ratio of the total
provide quantitative determination of the bispectral radiation-
(integrated spectral) radiance from a point on a specimen when
transfer properties of the specimen. (6)
irradiated at wavelength µ to the total radiance of the perfectly
NOTE 1—Typically, a reference detection system monitors the radiation
reflecting diffuser identically irradiated and viewed.
incident on the specimen. This reference detection system serves to
b~µ! [ L~µ!/L~µ! (3)
d
compensate for both temporal and spectral variations in the flux incident
upon the specimen, by normalization of readings from the instrument’s
4. Summary of Practice
emission detection system.
4.1 Procedures are given for selecting the types and oper-
3.2.5 diagonal elements—elements of a bispectral matrix
ating parameters of bispectrometers used to provide data for
for which irradiation and viewing wavelengths are equal.
the calculation of CIE tristimulus values and other colorimetric
3.2.6 diagonal fluorescence—the contribution of fluores-
values to quantify the colors of objects. The important steps in
cence to diagonal values of a bispectral radiance factor matrix,
the calibration of such instruments, and the material standards
due to the finite range of actual irradiation and viewing
requiredforthesesteps,aredescribed.Guidelinesaregivenfor
wavelengths when nominal irradiation and viewing wave-
the selection of specimens to obtain the highest measurement
lengths are equal (µ = l).
precision. Parameters are identified which must be specified
3.2.7 discretebispectralradiancefactor,B(µ,l)—thematrix
when bispectral photometric measurements are required in
defined for specified irradiation and viewing bandpass func-
specific test methods or other documents.
tions, and viewing-wavelength sampling interval (Dl) as
4.2 Inthispractice,themeasuringinstrument,abispectrom-
follows:
eter, is equipped with two separate monochromators. The first,
–
B~µ,l! [ b ~µ!· Dl (2)
l the irradiation monochromator, irradiates the specimen with
monochromatic light. The second, the viewing monochroma-
tor, analyzes the radiation leaving the specimen. A two-
dimensional array of bispectral photometric values is obtained
Available from National Institute of Standards and Technology (NIST), 100
Bureau Drive, Stop 3460, Gaithersburg, MD 20899–3460. by setting the irradiation monochromator at a series of fixed
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.
E2153–01
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 380-780 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
6.1 When describing the measurement of specimens by the interval. The spectral bandpass function should be symmetri-
cal, and approximately triangular or trapezoidal.
bispectral method, the following must be specified:
6.1.1 Thephotometricquantitydetermined,suchasDonald-
7.2.3 The irradiator should uniformly irradiate the sample.
son radiance factor or spectral efficiency factor.
7.3 Receiver—The receiver consists of the detector, a dis-
6.1.2 The geometry of irradiation and viewing, including
persive element and related optical components.
the following:
7.3.1 The detector must be a suitable photodetector such as
6.1.2.1 For bi-directional geometry, whether annular, cir-
a photoelectric device or silicon photodiode.The detector must
cumferential, or uniplanar measurement conditions are to be
be stable with time and have adequate responsivity over the
used, and the number and angular distribution of any multiple
wavelength range used.
beams.
7.3.2 The dispersive element, which provides energy in
6.1.2.2 For hemispherical geometry, whether total or diffuse
narrow wavelength bands across the visible spectral range,
measurement conditions (specular
...
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