ASTM D6531-00(2019)
(Test Method)Standard Test Method for Relative Tinting Strength of Aqueous Ink Systems by Instrumental Measurement
Standard Test Method for Relative Tinting Strength of Aqueous Ink Systems by Instrumental Measurement
SIGNIFICANCE AND USE
5.1 Tinting strength is an essential property of printing ink dispersions. Although results on bulk tints do not guarantee equivalency of dry printed films, they provide useful parameters for quality control of production batches of bases and finished inks. Test results may also be used for color matching purposes.
SCOPE
1.1 This test method covers the procedure for determining the relative tinting strength of waterbased ink systems using a computer-aided spectrophotometer.
1.2 This test method is applicable to waterbased printing inks and bases to be used primarily in flexographic and gravure printing applications.
1.3 This test method applies only to single, non-fluorescent pigmented colors and black ink systems for which there is a reference standard containing a pigment of the identical color index name and number.
1.4 The procedure in this test method specifies placing tinted samples in a cuvette for spectrophotometric measurements. The use of thick wet drawdowns as in Test Methods D2066 are inappropriate due to severe floating problems with aqueous systems.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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.
1.7 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.
General Information
Relations
Standards Content (Sample)
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: D6531 − 00 (Reapproved 2019)
Standard Test Method for
Relative Tinting Strength of Aqueous Ink Systems by
Instrumental Measurement
This standard is issued under the fixed designation D6531; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 ASTM Standards:
1.1 This test method covers the procedure for determining
D2066Test Methods for Relative Tinting Strength of Paste-
the relative tinting strength of waterbased ink systems using a
Type Printing Ink Dispersions
computer-aided spectrophotometer.
D2244Practice for Calculation of Color Tolerances and
1.2 This test method is applicable to waterbased printing
Color Differences from Instrumentally Measured Color
inksandbasestobeusedprimarilyinflexographicandgravure
Coordinates
printing applications.
E691Practice for Conducting an Interlaboratory Study to
1.3 This test method applies only to single, non-fluorescent
Determine the Precision of a Test Method
pigmented colors and black ink systems for which there is a
E1331Test Method for Reflectance Factor and Color by
reference standard containing a pigment of the identical color
Spectrophotometry Using Hemispherical Geometry
index name and number.
E1347Test Method for Color and Color-Difference Mea-
surement by Tristimulus Colorimetry
1.4 The procedure in this test method specifies placing
E1349Test Method for Reflectance Factor and Color by
tinted samples in a cuvette for spectrophotometric measure-
Spectrophotometry Using Bidirectional (45°:0° or 0°:45°)
ments. The use of thick wet drawdowns as in Test Methods
Geometry
D2066 are inappropriate due to severe floating problems with
aqueous systems.
3. Terminology
1.5 The values stated in SI units are to be regarded as
3.1 Definitions related to color differences are covered in
standard. No other units of measurement are included in this
Practice D2244. The definitions of tinting strength terms are
standard.
given in Test Methods D2066.
1.6 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 A standard and unknown samples are each reduced to
responsibility of the user of this standard to establish appro-
the same concentration in a white tinting base then dispersed
priate safety, health, and environmental practices and deter-
on a paint shaker.
mine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accor-
4.2 The dispersed samples are transferred to cuvettes for
dance with internationally recognized principles on standard- reflectance measurements on a spectrophotometer. Hue and
ization established in the Decision on Principles for the
strength relative to the standard tint are computed.
Development of International Standards, Guides and Recom-
NOTE 1—The hue readings indicate the closeness of the unknown
mendations issued by the World Trade Organization Technical
sample to that of the standard.
Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 Tinting strength is an essential property of printing ink
dispersions. Although results on bulk tints do not guarantee
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.56 on Printing Inks. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2019. Published January 2019. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2000. Last previous edition approved in 2010 as D6531–00(2010). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D6531-00R19.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6531 − 00 (2019)
equivalency of dry printed films, they provide useful param- 9.4 Divide exact weight of ink by 0.02. The resulting
eters for quality control of production batches of bases and number represents the total weight of sample plus tinting base
finished inks. Test results may also be used for color matching for a 2% tint.Add tinting base accordingly. If the sample is a
purposes. base, divide the exact weight by 0.01. Add tinting base
accordingly to make a 1% tint. In both cases, total weight
6. Apparatus
should be approximately 50 g. The amount of colorant should
be adjusted so that, at the wavelength of calculation, the
6.1 GlassJars,capacityapprox.64g,33mmindiameterby
reflectance is approximately 0.40.
70 mm in height, with screw cap lids.
9.5 Place cap on jar and close tightly.
6.2 Paint Shaker.
9.6 Repeat 9.1 – 9.5 with the standard ink or base.
6.3 Spectrophotometer, with small-area view (10-mm
aperture, diffuse/8° geometry) and with a computer and soft-
9.7 Securely position the samples in the paint shaker.
ware to measure reflectance factor, calculate color differences
Positionthesamplesattheleadingedgeoftheshakertogetthe
by CIELAB 1976 equation. Tinting strength is calculated by a
most vigorous shaking action.
Kubelka-Monk equation transformed from the lowest tristimu-
9.8 Shake sample jars for five minutes.
lus value.Alternate instrumentation and software may be used
9.9 Stop the paint shaker and invert the sample jars. Shake
by agreement between producer and user, or different plant
for another five minutes.
locations.
9.10 Visually check the jars to make sure that the tints are
6.4 Disposable Cuvettes, 10 mm in diameter, with at least
uniform with no white remaining, especially in the corners of
one optically true face.
the jar. If any white remains, repeat 9.8 until it is completely
6.5 Disposable Pipettes 7-mL capacity, 3.5-mL bulb draw
mixed.
or suitable substitute.
9.11 Let the samples sit for five minutes so the air bubbles
6.6 Balance, capacity 100 g, accurate to 10 mg, preferably
can dissipate.
1 mg.
6.7 Black Electrical Tape.
10. Procedure for Spectrophotometric Measurements
6.8 Black Cover, 90 mm in diameter such as 1-lb ink can,
10.1 CalibratethespectrophotometerwithD65lightsource,
with interior painted flat black.
10° observer, and specular component included. (See 10.9.)
6.9 Ink Knives, small.
10.2 Referring to the manual of the software that is being
used, set the computer to measure the reflectance of the
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