ASTM D7195-06
(Guide)Standard Guide for Protocol for Setting Color Specifications for a Material
Standard Guide for Protocol for Setting Color Specifications for a Material
SIGNIFICANCE AND USE
The rejection of materials due to color is a common and expensive occurrence, and it is useful for a customer and producer to set a color specification with an associated tolerance before the transaction. This guide discusses the concept and details the ASTM standards to be used in the process.
SCOPE
1.1 This guide leads the user through the process for setting a color tolerance for a product or material. It points to the appropriate ASTM standards that affect each step of the process. It includes the discussion points on which the two parties must agree and provides caveats for various options selected.
1.2 This guide does not suggest numerical values for tolerances. These values must be agreed upon by the two parties involved.
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.
General Information
Relations
Standards Content (Sample)
Designation:D7195 −06
Standard Guide for
Protocol for Setting Color Specifications for a Material
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 Measurement of Reflection and Transmission Properties
of Materials (Withdrawn 2012)
1.1 This guide leads the user through the process for setting
E253 Terminology Relating to Sensory Evaluation of Mate-
a color tolerance for a product or material. It points to the
rials and Products
appropriate ASTM standards that affect each step of the
E284 Terminology of Appearance
process. It includes the discussion points on which the two
E308 PracticeforComputingtheColorsofObjectsbyUsing
parties must agree and provides caveats for various options
the CIE System
selected.
E805 Practice for Identification of Instrumental Methods of
1.2 This guide does not suggest numerical values for toler-
Color or Color-Difference Measurement of Materials
ances. These values must be agreed upon by the two parties
E1164 PracticeforObtainingSpectrometricDataforObject-
involved.
Color Evaluation
1.3 This standard does not purport to address all of the E1345 Practice for Reducing the Effect of Variability of
safety concerns, if any, associated with its use. It is the
Color Measurement by Use of Multiple Measurements
responsibility of the user of this standard to establish appro- E1347 Test Method for Color and Color-Difference Mea-
priate safety and health practices and determine the applica-
surement by Tristimulus Colorimetry
bility of regulatory limitations prior to use. E1499 Guide for Selection, Evaluation, and Training of
Observers
2. Referenced Documents
E1708 Practice for Electronic Interchange of Color and
Appearance Data
2.1 ASTM Standards:
E1808 Guide for Designing and Conducting Visual Experi-
D523 Test Method for Specular Gloss
ments
D1729 Practice for Visual Appraisal of Colors and Color
E2214 Practice for Specifying and Verifying the Perfor-
Differences of Diffusely-Illuminated Opaque Materials
mance of Color-Measuring Instruments
D2244 Practice for Calculation of Color Tolerances and
Color Differences from Instrumentally Measured Color
2.2 CIE Publications
rd 4
Coordinates
CIE 15:2004 Colorimetry, 3 edition
D3134 Practice for Establishing Color and Gloss Tolerances
D3964 Practice for Selection of Coating Specimens for 3. Terminology
Appearance Measurements
3.1 Definitions—For definitions of terms related to this
D4086 Practice for Visual Evaluation of Metamerism
guide see Terminology E253 and Terminology E284.
D4449 Test Method for Visual Evaluation of Gloss Differ-
ences Between Surfaces of Similar Appearance
4. Summary of Guide
D5531 GuideforPreparation,Maintenance,andDistribution
4.1 This guide describes the process for establishing a color
of Physical Product Standards for Color and Geometric
specification for a material, including the decision as to
Appearance of Coatings
whether this specification will be based on visual or instrumen-
E179 Guide for Selection of Geometric Conditions for
tal methods.
4.2 General considerations of appearance, evaluation of
This guide is under the jurisdiction of ASTM Committee D01 on Paint and
observers, and measurement techniques are included.
Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.26 on Optical Properties.
Current edition approved April 1, 2006. Published April 2006. DOI: 10.1520/
D7195-06. The last approved version of this historical standard is referenced on
For referenced ASTM standards, visit the ASTM website, www.astm.org, or www.astm.org.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM AvailablefromU.S.NationalCommitteeoftheCIE(InternationalCommission
Standards volume information, refer to the standard’s Document Summary page on on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
the ASTM website. St., Salem, MA 01970.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7195−06
4.3 It begins the process of setting a tolerance by first the two parties involved. For years, color tolerances were set
selecting a standard or target color for the material, including up as boxes. However, it is now possible and desirable to use
the production, measurement, and storage of that target. elliptical tolerancing.
4.4 It next identifies methods to establish acceptable color
7.4 In most cases, the limits of acceptability will be greater
tolerances.
than a just perceptible difference, but in some cases, the
tolerance may be less than a perceptible difference. If it is less
4.5 Finally, it discusses reporting techniques.
than a perceptible difference, then instrumental methods will
have to be used. Both the producer and the customer should
5. Significance and Use
refer to Practice E2214.
5.1 The rejection of materials due to color is a common and
expensive occurrence, and it is useful for a customer and 7.5 While the goal is to have an agreed color specification
with an acceptable tolerance for both the producer and the
producer to set a color specification with an associated toler-
ance before the transaction. This guide discusses the concept customer, each party must carefully consider their position.
The producer must know that they are able to control the color
and details the ASTM standards to be used in the process.
inproductiontothelevelspecifiedwithoutexcessivewasteand
6. Introduction undue loss. The customer must be assured that the tolerance is
suchthatthecolorofthegoodswillbefunctionallyacceptable.
6.1 A common reason stated for rejection of goods or
materials is that the product color does not meet expectations.
7.6 Color is one aspect of the appearance of a material.
The best way to avoid the problem of returned goods or
Other appearance parameters include, but are not limited to,
materials because of color is to establish a color specification
gloss, haze, and texture. In order to compare the color of a test
with an associated tolerance. Then the producer can be
material to a target material, either visually or instrumentally,
confident that if they supply material that falls within the color
the other aspects of appearance should be the same, or as
specification, the customer will accept the color of the product.
similar as possible. Test Method D4449 covers the visual
evaluation of gloss, while Test Method D523 covers instru-
6.2 To supply color within specification consistently re-
mental gloss measurement.
quires production that is in statistical control, and a program of
color measurement and evaluation
7.7 Since it is not always possible to have all appearance
parameters the same or even if they are the same, it is
6.3 This guide will lead the user through the decision-
important to use established viewing conditions. These include
making process and point to the appropriate ASTM standards
the illumination, the positioning of the standard and specimen,
that are pertinent to each step. It will include the discussion
andthereceptorsystem,whetherhumanorinstrumental.Ifone
points on which the two parties must agree and will provide
is trying to have instrumental readings that correlate with the
caveats for various options selected.
visual appearance of a material, one needs to establish consis-
tency between the visual situation and the instrumental set up.
7. General Discussions
Guide E179 discusses the terminology and instrumentation for
7.1 In setting up the specification, one must first decide
evaluating appearance characteristics. Some of the consider-
whether there will be a visual or instrumental evaluation of the
ations when choosing the geometry of evaluation are:
color.Observershavedifferentcolorperceptionskills.Ahighly
7.7.1 What are your internal needs such as formulation,
trained colorist can see very minute color differences whereas
quality control, auditing, trouble shooting?
the more casual observer or color-anomalous observer would
7.7.2 What are your customer’s specifications and needs?
not normally detect very small differences. Additionally, the
7.7.3 Do you want the numbers to match visual evaluation?
visual abilities or perception levels of observers, may vary
betweenpersonsandovertimewithinanindividual.Thusifthe 7.7.4 If the gloss or surface texture of the standard and
color of the material will be evaluated visually, we must ensure specimen are different, do you want specimen’s gloss or grain
consistent conditions for the evaluation. Guide E1499 provides levels to produce the same colorimetric values when mea-
more detailed information. sured?
7.7.5 Do you want to deal with a small or large process
7.2 Numerous advances have occurred in both the accuracy
window?
and repeatability of color measurement instruments. However,
theremaystillbeconsiderabledifferencesbetweeninstruments
7.8 It is important to have the producer and the customer
of different make, type, and geometry. Advances have also
agree on the target color and the criterion for acceptance. For
occurredintheequationsandsoftwareprogramsforevaluating
many users the final criterion is visual acceptance, that is,
color and color quality control. It is not uncommon for the
visual appearance is the final deciding factor. However, some
specification to be set numerically and evaluated by instrumen-
usershavedemonstratedthatmoreconsistentproductqualityis
tal measurement, but then the question “what should my
obtainedinstrumentally,avoidingthe“finalvisualinspection.”
tolerance be?” must be resolved.
Once the color is agreed upon, then one should decide whether
to use visual or objective standards and tolerances.
7.3 A number of color difference calculations are widely
7.8.1 Someoftheadvantagesofusingadigitalstandardare:
used throughout industry. See Practice D2244 for more details
on the color difference and color tolerance equations. Which 7.8.1.1 Both supplier and customer have the same absolute
color-difference metric will be used should be agreed upon by numbers to judge against, the same starting point,
D7195−06
TABLE 1 Summary of ASTM Standard Used
7.8.1.2 Reduced costs of making and maintaining master
standards, Color Specification Objective ASTM Standard Reference
7.8.1.3 Easy to co
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