ASTM D7195-21

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7195 − 16a D7195 − 21
Standard Guide for
Setting Object Color Specifications
This standard is issued under the fixed designation D7195; 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.
1. Scope
1.1 This guide leads the user through a process for establishing color specifications, including the target color and allowable
tolerances. It refers to the appropriate ASTM standards that more thoroughly describe each step of the process beginning with
expectations, encompassing caveats within the process and finally concluding with reporting.
1.2 This guide does not suggest numerical values for tolerances. These values must be agreed upon by the parties involved.
1.3 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
D523 Test Method for Specular Gloss
D1003 Test Method for Haze and Luminous Transmittance of Transparent Plastics
D1729 Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
D3134 Practice for Establishing Color and Gloss Tolerances
D3964 Practice for Selection of Coating Specimens for Appearance Measurements
D4086 Practice for Visual Evaluation of Metamerism
D4449 Test Method for Visual Evaluation of Gloss Differences Between Surfaces of Similar Appearance
D5531 Guide for Preparation, Maintenance, and Distribution of Physical Product Standards for Color and Geometric
Appearance of Coatings
E179 Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of Materials
E284 Terminology of Appearance
E308 Practice for Computing the Colors of Objects by Using the CIE System
E805 Practice for Identification of Instrumental Methods of Color or Color-Difference Measurement of Materials
E1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation
E1345 Practice for Reducing the Effect of Variability of Color Measurement by Use of Multiple Measurements
This guide is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.04 on Color and Appearance
Analysis.
Current edition approved Aug. 1, 2016June 1, 2021. Published September 2016June 2021. Originally approved in 2006. Last previous edition approved in 2016 as
D7195D7195 – 16a. – 16. DOI: 10.1520/D7195-16A.10.1520/D7195-21.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7195 − 21
E1347 Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry
E1499 Guide for Selection, Evaluation, and Training of Observers
E1708 Practice for Electronic Interchange of Color and Appearance Data
E1808 Guide for Designing and Conducting Visual Experiments
E2214 Practice for Specifying and Verifying the Performance of Color-Measuring Instruments
E2867 Practice for Estimating Uncertainty of Test Results Derived from Spectrophotometry
2.2 CIE Publications:
CIE Publication 015 Colorimetry
3. Terminology
3.1 Definitions—For definitions of terms related to this guide see Terminology E284.
4. Summary of Guide
4.1 This guide describes the process for establishing color specifications for a material, including the decision as to whether this
specification will be based on visual or instrumental methods.
4.2 General considerations of appearance, evaluation of observers, and measurement techniques are included.
4.3 It begins the process of setting a tolerance by first selecting a standard or target color for the material, including the production,
measurement, and storage of that target.
4.4 It next identifies methods to establish acceptable color tolerances.
4.5 Finally, it discusses reporting techniques.
5. Significance and Use
5.1 The rejection of materials due to color is a common and expensive occurrence, and it is useful for a customer and producer
to set color specifications with an associated tolerance before the transaction. This guide discusses the concept and details the
ASTM standards to be used in the process.
6. Introduction
6.1 A common reason stated for rejection of goods or materials is that the product color does not meet expectations. The best way
to avoid the problem of returned goods or materials because of color is to establish color specifications with associated tolerances.
Then the producer can be confident that if they supply material that falls within the specification, the customer will accept the
product.
6.2 To supply product within specification consistently requires production that is under statistical process control, and a program
of color measurement and evaluation.
6.3 This guide will lead the user through the decision-making process and point to the appropriate ASTM standards that are
pertinent to each step. It will include the discussion points on which the two parties must agree and will provide caveats for various
options selected.
7. General Discussions
7.1 In setting up the specification, one must first decide whether there will be a visual or instrumental evaluation of the color.
Observers have different color perception skills. A highly trained colorist can see very minute color differences whereas the more
casual observer or color-anomalous observer would not normally detect very small differences. Additionally, the visual abilities
or perception levels of observers, may vary between persons and over time within an individual. Thus if the color of the material
Available from CIE (International Commission on Illumination), http://www.cie.co.at or http://www.techstreet.com.
D7195 − 21
will be evaluated visually, we must ensure consistent conditions for the evaluation. Guide E1499 provides detailed information
about the selection of observers. Guide E1808 provides guidance on how to conduct critical visual observations.
7.2 Numerous advances have occurred in both the accuracy and repeatability of color measurement instruments. However, there
may still be considerable differences between instruments of different make, type, and geometry. Advances have also occurred in
the equations and software programs for evaluating color and color quality control. It is not uncommon for the specification to be
set numerically and evaluated by instrumental measurement, but then the question, “what should my tolerance be?” must be
resolved.
7.3 A number of color difference calculations are widely used throughout industry. See Practice D2244 for more details on color
difference and color tolerance equations. Which color-difference metric will be used should be agreed upon by the two parties
involved. For years, color tolerances were set up as rectangular tolerancing. In some industries the phrase “box tolerancing” is the
accepted terminology. However, elliptical tolerancing is preferred.
7.4 In most cases, the limits of acceptability will be greater than a just perceptible difference, but in some cases, the tolerance may
be less than a perceptible difference. If it is less than a perceptible difference, then instrumental methods should be used. Both the
producer and the customer should refer to Practice E2214.
7.5 While the goal is to have an agreed color specification with an acceptable tolerance for both the producer and the customer,
each party must carefully consider their position. The producer should be assured that they are able to control the color in
production to the level specified without excessive waste and undue loss. The customer should be assured that the tolerance is such
that the color of the goods will be acceptable.
7.6 Color is one aspect of the appearance of a material. Other appearance parameters include, but are not limited to, gloss, haze,
and texture. In order to compare the color of a test material to a target material, either visually or instrumentally, all aspects of
appearance should be the same, or as similar as possible. Test Method D4449 covers the visual evaluation of gloss difference, while
Test Method D523 covers instrumental gloss measurement. Test Method D1003 covers the measurement of transmission and haze
of transparent plastics.
7.7 It is important to use established and consistent viewing conditions. These include the illumination, the positioning of the
standard and specimen, and the receptor system, whether human or instrumental. If one is trying to have instrumental readings that
correlate with the visual appearance of a material, one needs to establish consistency between the visual situation and the
instrumental set up. Guide E179 discusses the terminology and instrumentation for evaluating appearance characteristics. Some
of the considerations when choosing the geometry of evaluation are:
7.7.1 What are one’s internal needs such as formulation, quality control, auditing, trouble shooting?
7.7.2 What are one’s customer’s specifications and needs?
7.7.3 Does one want the numbers to match visual evaluation?
7.7.4 If the gloss or surface texture of the standard and specimen are different, does one want specimen’s gloss or grain levels to
produce the same colorimetric values as the standard when measured?
7.7.5 Does one want to deal with a small or large process window?
7.8 It is important to have the producer and the customer agree on the target color and the criteria for acceptance.
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