ASTM C609-07

Standard Test Method for Measurement of Light Reflectance Value and Small Color Differences Between Pieces of Ceramic Tile

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 the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Apr-2007
• ICS: 91.100.25 - Terracotta building products
• Technical Committee: C21 - Ceramic Whitewares and Related Products
• Drafting Committee: C21.06 - Ceramic Tile

Relations

• Replaces: ASTM C609-90(2000) - Standard Test Method for Measurement of Small Color Differences Between Ceramic Wall or Floor Tile
• Effective Date: 01-May-2007
• Replaced By: ASTM C609-07(2014) - Standard Test Method for Measurement of Light Reflectance Value and Small Color Differences Between Pieces of Ceramic Tile
• Effective Date: 01-Jan-2014

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:C609 −07
StandardTest 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 2. Referenced Documents
2
1.1 This test method covers the measurement of Light 2.1 ASTM Standards:
Reflectance Value (LRV) and visually small color difference C242 Terminology of Ceramic Whitewares and Related
between pieces of glazed or unglazed ceramic tile, using any Products
spectrophotometer that meets the requirements specified in the D2244 Practice for Calculation of Color Tolerances and
test method. LRV and the magnitude and direction of the color Color Differences from Instrumentally Measured Color
difference are expressed numerically, with sufficient accuracy Coordinates
for use in product specification. E259 Practice for Preparation of Pressed Powder White
Reflectance Factor Transfer Standards for Hemispherical
1.2 LRV may be measured for either solid-colored tile or
and Bi-Directional Geometries
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, ∆E and ∆E —the vector sum of the
H
be measured for solid-color tiles. Small color difference
* * * *
three component differences ∆L , ∆a , and ∆b for ∆E and
between tile that have a multicolored, speckled, or textured
∆L ,∆a ,∆b for ∆E . 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,
useoftheHunterequations. ∆E isexpressedinunitsofjudds,
H
*
fluorescent and daylight illuminant conditions. The use of
while ∆E is a unit-less value. Either form of the ∆E can be
multiple illuminants allows the color difference measurement
solved for using the equation shown in 10.3. For both the
tobemadewithouttheriskofwronglyacceptingamatchwhen
CIELAB and Hunter equations, the values ∆ L, ∆a, and ∆b 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
∆L 5 L 2 L
t r
as the standard. The values given in parentheses are for
∆a 5 a 2 a
t r
information only.
∆b 5 b 2 b
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 and health practices and determine the applica-
bility of regulatory limitations prior to use. The quantity ∆E has a positive value and it describes the
magnitude but not the direction of color difference between the
test specimen and the reference specimen. The direction of
1
ThistestmethodisunderthejurisdictionofASTMCommitteeC21onCeramic
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 May 1, 2007. Published May 2007. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approvedin1967.Lastpreviouseditionapprovedin2000asC609 – 90(2000).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0609-07. the ASTM website.
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C609−07
color difference depends upon the algebraic signs of the 3.1.7 reproducibility—the standard deviation of results ob-
components ∆ L, ∆a, and ∆b. A positive ∆L value means that tained by different operators using the same or different types
the test specimen is lighter than the reference against which it of instruments in different laboratories.
is being compared, and a negative ∆Lvalue means that the test
3.1.8 standard—the plaque or other media of established
specimen is darker. However, the algebraic signs of chroma-
tristimulus value, against which standardization of the
...