ASTM E2152-12(2023)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2152 − 12 (Reapproved 2023)
Standard Practice for
Computing the Colors of Fluorescent Objects from
Bispectral Photometric Data
This standard is issued under the fixed designation E2152; 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. Procedures for such computation are contained in this practice. This
practice also contains procedures for computing illuminant-specific spectral radiance factor values
from illuminant-independent bispectral photometric data.
1. Scope 2. Referenced Documents
1.1 This practice provides the values and practical compu- 2.1 ASTM Standards:
tation procedures needed to obtain tristimulus values, desig- E284 Terminology of Appearance
nated X, Y, Z and X , Y , Z for the CIE 1931 and 1964 E308 Practice for Computing the Colors of Objects by Using
10 10 10
observers, respectively, from bispectral photometric data for the CIE System
the specimen. Procedures for obtaining such bispectral photo- E2153 Practice for Obtaining Bispectral Photometric Data
metric data are contained in Practice E2153. for Evaluation of Fluorescent Color
2.2 CIE Standards:
1.2 Procedures for conversion of results to color spaces that
CIE 15 Colorimetry
are part of the CIE system, such as CIELAB and CIELUV are
2.3 ISO Standards:
contained in Practice E308.
ISO 11476 Paper and Board—Determination of CIE-
1.3 This standard may involve hazardous materials, 4
Whiteness, C/2 Degrees
operations, and equipment. This standard does not purport to
address all of the safety concerns, if any, associated with its
3. Terminology
use. It is the responsibility of the user of this standard to
3.1 Definitions—The definitions contained in Terminology
establish appropriate safety, health, and environmental prac-
E284 are applicable to this practice.
tices and determine the applicability of regulatory limitations
3.2 Definitions of Terms Specific to This Standard:
prior to use.
3.2.1 bispectrometer, n—an optical instrument equipped
1.4 This international standard was developed in accor-
with a source of irradiation, two monochromators, and a
dance with internationally recognized principles on standard-
detection system, such that a specimen can be measured at
ization established in the Decision on Principles for the
independently-controlled irradiation and viewing wavelengths.
Development of International Standards, Guides and Recom-
The bispectrometer is designed to allow for calibration to
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
This practice is under the jurisdiction of ASTM Committee E12 on Color and Standards volume information, refer to the standard’s Document Summary page on
Appearance and is the direct responsibility of Subcommittee E12.05 on Fluores- the ASTM website.
cence. Available from CIE (International Commission on Illumination) at www.cie-
Current edition approved June 1, 2023. Published July 2023. Originally approved .co.at or www.techstreet.com.
in 2001. Last previous edition approved in 2017 as E2152 – 12 (2017). DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/E2152-12R23. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2152 − 12 (2023)
provide quantitative determination of the bispectral radiation- color for any desired illuminant and observer. The advantage of
transfer properties of the specimen (1). this method is that it provides a comprehensive characteriza-
tion of the specimen’s radiation-transfer properties, without the
NOTE 1—Typically, a reference detection system monitors the radiation
inaccuracies associated with source simulation and various
incident on the specimen. This reference detection system serves to
methods of approximation.
compensate for both temporal and spectral variations in the flux incident
upon the specimen, by normalization of readings from the instrument’s
emission detection system.
6. Procedure
3.2.2 diagonal elements, n—elements of a bispectral matrix
6.1 Selecting Standard Observer—Select standard observer
for which irradiation and viewing wavelengths are equal.
according to the guidelines of Practice E308.
3.2.3 fluorescence, n—this standard uses the term “fluores-
6.2 Selecting Illuminants—Select illuminants that are simi-
cence” as a general term, including both true fluorescence
lar to the light under which the objects will be viewed or for
-8
(with a luminescent decay time of less than 10 s) and
which their colors will be specified or evaluated. In general,
phosphorescence with a delay time short enough to be indis-
follow the recommendations of Practice E308. For fluorescent
tinguishable from fluorescence for the purpose of colorimetry.
samples, however, special attention must be given to the
3.2.4 off-diagonal element, n—any element of a bispectral relative UV content of the selected illuminants and the light
matrix for which irradiation and viewing wavelengths are not
under which the objects will be viewed.
equal. 6.2.1 When object will be viewed indoors, by daylight
filtered through a glass window, use values for the extended
4. Summary of Practice
version of Illuminant C defined in ISO 11476.
6.2.2 When object will be viewed outdoors, by unfiltered
4.1 Procedures—Procedures are given for computing from
daylight, use values for CIE Illuminant D65, or other daylight
bispectral photometric measurements the CIE tristimulus val-
illuminants, as defined by the formulas developed by Judd, and
ues X, Y, Z for the CIE 1931 standard observer and the CIE
presented in CIE 15.
1964 supplementary standard observer. While recognizing the
6.2.3 When object will be viewed under well-defined spe-
CIE recommendation of numerical integration at 1 nm intervals
cial conditions of irradiation which are not similar to any
(in CIE 15) as the basic definition, this practice is limited in
standard illuminant, a provisional illuminant may be defined.
scope to measurements and calculations using spectral inter-
Such a provisional illuminant must represent the relative
vals greater than or equal to 5 nm.
spectral irradiance upon the object surface under these special
4.2 Calculations—CIE tristimulus values X, Y, Z or X ,
conditions.
Y , Z are calculated by numerical summation of the prod-
10 10
ucts of weighting factors for selected illuminants and observers
7. Calculation
with the bispectral Donaldson radiance factor of the specimen.
7.1 Calculation of Colorimetric Quantities—Use the
The tristimulus values so calculated may be converted to
method of calculating tristimulus values at 5 nm intervals over
coordinates in a more nearly uniform color space such as
the viewing wavelength range 380 nm to 780 nm, and irradia-
CIELAB or CIELUV.
tion wavelength range 300 nm to 780 nm.
5. Significance and Use
7.2 Calculation of Tristimulus Values—The calculation pro-
cedures described below involve numerical summation of the
5.1 The bispectral or two-monochromator method is the
products of the Donaldson radiance factor of the specimen and
definitive method for the determination of the general
a bispectral factor derived from the tabulated standard illumi-
radiation-transfer properties of fluorescent specimens (2). In
nant and observer functions. After normalization, the sums are
this method, the measuring instrument is equipped with two
the CIE tristimulus values X, Y, Z (3, 2, 1).
separate monochromators. The first, the irradiation
7.2.1 Application of Illuminant Weights—Select the desired
monochromator, irradiates the specimen with monochromatic
CIE standard illuminant from Tables given in Practice E308.
light. The second, the viewing monochromator, analyzes the
Multiply each element D(μ,λ) of the specimen’s Donaldson
radiation leaving the specimen. A two-dimensional array of
matrix by the tabulated value of the relative spectral power of
bispectral photometric values is obtained by setting the irra-
the illuminant Φ at the element’s irradiation wavelength (μ).
diation monochromator at a series of fixed wavelengths (μ) in
7.2.2 Calculation of Stimulus Function—Obtain the sum
the ultraviolet and visible range, and for each μ, using the
over μ of these products at 5 nm intervals over the wavelength
viewing monochromator to record readings for each wave-
range 300 nm to 780 nm. The sum obtained at each viewing
length (λ) in the visible range. The resulting array, once
wavelength λ is the value of the specimen’s stimulus function
properly corrected, is known as the Donaldson matrix, and the
(relative spectral radiance) F(λ), under the specified conditions
value of each element (μ,λ) of this array is here described as the
of irradiation. From these values, either tristimulus values or
Donaldson radiance factor (D(μ,λ)). The Donaldson radiance
spectral radiance factor values may be derived.
factor is an instrument- and illuminant-independent photomet-
ric property of the specimen, and can be used to calculate its
F λ 5 Φ μ D μ,λ (1)
~ ! ~ ! ~ !
(
μ5300
7.2.3 Derivation of Tristimulus Values—Use the color-
The boldface numbers in parentheses refer to a list of references at the end of
this standard. matching functions selected in 6.1. Multiply the specimen’s
E2152 − 12 (2023)
stimulus function at each viewing wavelength (λ) by the fluorescence components may be employed, description of
corresponding tabulated values of the observer color-matching such calculations lies outside the scope of this standard.
functions. Obtain the sum of these spectral products at 5 nm
7.6 Abridged Calculation Procedures:
intervals over the wavelength range 380 nm to 780 nm:
7.6.1 Wavelength Intervals of Greater than 5 nm—When
data for D(μ,λ) are not available at 5 nm intervals, estimated
X 5 k xH λ F λ (2)
~ ! ~ !
(
values at 5 nm intervals should be derived by appropriate
λ5380
interpolation, as described in Annex A1.
7.6.2 Viewing Wavelength Range Less Than 380 nm to 780
Y 5 k yH λ F λ
~ ! ~ !
(
λ5380 nm—When data for D(μ,λ) are not available for the full
viewing wavelength range, add the illuminant or obs
...