ASTM C609-23
(Test Method)Standard Test Method for Measurement of Light Reflectance Value and Small Color Differences Between Pieces of Ceramic Tile
Standard Test Method for Measurement of Light Reflectance Value and Small Color Differences Between Pieces of Ceramic Tile
SIGNIFICANCE AND USE
5.1 This test method describes the means of determining the LRV of a tile specimen. Certain building codes require the use of materials rated by LRV. Application of this test method provides the means for rating ceramic tile. LRVs reported for ceramic tile should include reference to the observer and illuminant for which the rating is valid.
5.2 LRV is a property dependent on the overall color of a tile specimen. Control of LRV is achieved through control of color and adherence to color specifications will govern the acceptability of a product with respect to LRV. Therefore, a product cannot be judged as having an unacceptable LRV unless the color of the product is found to be unacceptable.
5.3 Mixtures of several tile products are commonly installed on a surface, requiring a means to calculate LRV for a product mix. The rating obtained for an individual tile product can be used to calculate the LRV for a product mix using the following equation:
where:
n = number of products included in the mix, p1 to n = the proportion of the surface area taken up by each product; the sum of p1 to pn must equal one), and LRV1 to n = the LRV for each product used. For example, a mixture of two products is used on a surface. Two thirds of the surface area is covered by product A with a LRV of 75 %, and one third of the surface is covered by product B with an LRV of 60 % (see Fig. 2). Using the equation, the product mix is found to have an LRV of 70 %.
FIG. 2 Example of Product Mix Used on Surface
5.4 The test method described herein provides instrumental means as the basis for judging color difference. Magnitude of color difference between pairs of ceramic tile can be determined and expressed in numerical terms.
5.5 Based on interlaboratory investigation,3 color difference ΔE of plain-colored tile, if determined in accordance with this test method, should give excellent reproducibility with a standard deviation of not more than σ = ±...
SCOPE
1.1 This test method covers the measurement of Light Reflectance Value (LRV) and visually small color difference between pieces of glazed or unglazed ceramic tile, using any spectrophotometer that meets the requirements specified in the test method. LRV and the magnitude and direction of the color difference are expressed numerically, with sufficient accuracy for use in product specification.
1.2 LRV may be measured for either solid-colored tile or tile having a multicolored, speckled, or textured surface. For tile that are not solid-colored, an average reading should be obtained from multiple measurements taken in a pattern representative of the overall sample as described in 9.2 of this test method. Small color difference between tiles should only be measured for solid-color tiles. Small color difference between tile that have a multicolored, speckled, or textured surface are not valid.
1.3 For solid colored tile, a comparison of the test specimen and reference specimen should be made under incandescent, fluorescent and daylight illuminant conditions. The use of multiple illuminants allows the color difference measurement to be made without the risk of wrongly accepting a match when the tiles being compared are metamers (see 3.1.4).
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard.
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standard...
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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: C609 − 23
Standard Test Method for
Measurement of Light Reflectance Value and Small Color
1
Differences Between Pieces of Ceramic Tile
This standard is issued under the fixed designation C609; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers the measurement of Light
Reflectance Value (LRV) and visually small color difference
2. Referenced Documents
between pieces of glazed or unglazed ceramic tile, using any
2
2.1 ASTM Standards:
spectrophotometer that meets the requirements specified in the
C242 Terminology of Ceramic Whitewares and Related
test method. LRV and the magnitude and direction of the color
Products
difference are expressed numerically, with sufficient accuracy
D2244 Practice for Calculation of Color Tolerances and
for use in product specification.
Color Differences from Instrumentally Measured Color
1.2 LRV may be measured for either solid-colored tile or
Coordinates
tile having a multicolored, speckled, or textured surface. For
E284 Terminology of Appearance
tile that are not solid-colored, an average reading should be
obtained from multiple measurements taken in a pattern
3. Terminology
representative of the overall sample as described in 9.2 of this
3.1 Definitions:
test method. Small color difference between tiles should only
*
3.1.1 color difference, ΔE and ΔE , n—the vector sum of
H
be measured for solid-color tiles. Small color difference * * * *
the three component differences ΔL , Δa , and Δb for ΔE and
between tile that have a multicolored, speckled, or textured
ΔL , Δa , Δb for ΔE . The superscript * indicates color
H H H H
surface are not valid.
difference based on the use of CIELAB color space equations,
1.3 For solid colored tile, a comparison of the test specimen
while the subscript H indicates color difference based on the
and reference specimen should be made under incandescent, use of the Hunter equations. ΔE is expressed in units of judds,
H
*
fluorescent and daylight illuminant conditions. The use of
while ΔE is a unit-less value. Either form of the ΔE can be
multiple illuminants allows the color difference measurement
solved for using the equation shown in 10.3. For both the
to be made without the risk of wrongly accepting a match when
CIELAB and Hunter equations, the values ΔL, Δa, and Δb are
the tiles being compared are metamers (see 3.1.4).
obtained by calculating the component differences as follows:
1.4 The values stated in inch-pound units are to be regarded ΔL 5 L 2 L
t r
as standard. The values given in parentheses are provided for Δa 5 a 2 a
t r
Δb 5 b 2 b
information only and are not considered standard.
t r
1.5 This standard does not purport to address all of the
where:
safety concerns, if any, associated with its use. It is the
t = test specimen, and
responsibility of the user of this standard to establish appro-
r = reference specimen.
priate safety, health, and environmental practices and deter-
The quantity ΔE has a positive value and it describes the
mine the applicability of regulatory limitations prior to use.
magnitude but not the direction of color difference between the
1.6 This international standard was developed in accor-
test specimen and the reference specimen. The direction of
dance with internationally recognized principles on standard-
color difference depends upon the algebraic signs of the
ization established in the Decision on Principles for the
components ΔL, Δa, and Δb. A positive ΔL value means that
Development of International Standards, Guides and Recom-
the test specimen is lighter than the reference against which it
is being compared, and a negative ΔL value means that the test
1
This test method is under the jurisdiction of ASTM Committee C21 on Ceramic
Whitewares and Related Products and is the direct responsibility of Subcommittee
2
C21.06 on Ceramic Tile. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2023. Published October 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1967. Last previous edition approved in 2020 as C609 – 20. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0609-23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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: C609 − 20 C609 − 23
Standard Test Method for
Measurement of Light Reflectance Value and Small Color
1
Differences Between Pieces of Ceramic Tile
This standard is issued under the fixed designation C609; 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 test method covers the measurement of Light Reflectance Value (LRV) and visually small color difference between pieces
of glazed or unglazed ceramic tile, using any spectrophotometer that meets the requirements specified in the test method. LRV and
the magnitude and direction of the color difference are expressed numerically, with sufficient accuracy for use in product
specification.
1.2 LRV may be measured for either solid-colored tile or tile having a multicolored, speckled, or textured surface. For tile that
are not solid-colored, an average reading should be obtained from multiple measurements taken in a pattern representative of the
overall sample as described in 9.2 of this test method. Small color difference between tiles should only be measured for solid-color
tiles. Small color difference between tile that have a multicolored, speckled, or textured surface are not valid.
1.3 For solid colored tile, a comparison of the test specimen and reference specimen should be made under incandescent,
fluorescent and daylight illuminant conditions. The use of multiple illuminants allows the color difference measurement to be made
without the risk of wrongly accepting a match when the tiles being compared are metamers (see 3.1.4).
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are provided for
information only and are not considered standard.
1.5 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 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
2.1 ASTM Standards:
C242 Terminology of Ceramic Whitewares and Related Products
D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
1
This test method is under the jurisdiction of ASTM Committee C21 on Ceramic Whitewares and Related Products and is the direct responsibility of Subcommittee C21.06
on Ceramic Tile.
Current edition approved April 1, 2020Oct. 1, 2023. Published April 2020October 2023. Originally approved in 1967. Last previous edition approved in 20192020 as
C609 – 07 (2019).C609 – 20. DOI: 10.1520/C0609-20.10.1520/C0609-23.
2
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
1
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C609 − 23
E259 Practice for Preparation of Pressed Powder White Reflectance Factor Transfer Standards for Hemispherical and
Bi-Directional Geometries
E284 Terminology of Appearance
3. Terminology
3.1 Definitions:
* * * * *
3.1.1 color difference, ΔE and ΔE , n—the vector sum of the three component differences ΔL , Δa , and Δb for ΔE and ΔL ,
H H
Δa , Δb for ΔE . The superscript * indicates color difference based on the use of CIELAB color space equations, while the
H H H
*
subscript H indicates color difference based on the use of the Hunter equations. ΔE is expressed in units of judds, while ΔE is
H
a unit-less value. Either form of the ΔE can be solved for using the equation shown in 10.3. For both the CIELAB and Hunter
equations, the values ΔL, Δa, and Δb are obtained by calculating the component differences as follows:
ΔL 5 L 2 L
t r
Δa 5 a 2 a
t r
Δb 5 b 2 b
t r
where:
t = test specimen, and
r = reference s
...
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