ASTM D6531-00

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D6531–00
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope E1349 Test Method for Reflectance Factor and Color by
Spectrophotometer Using Bidirectional Geometry
1.1 This test method covers the procedure for determining
the relative tinting strength of waterbased ink systems using a
3. Terminology
computer-aided spectrophotometer.
3.1 Definition related to color differences are covered in
1.2 This test method is applicable to waterbased printing
Test Method D2244. The definitions of tinting strength terms
inksandbasestobeusedprimarilyinflexographicandgravure
are given in Test Methods D2066.
printing applications.
1.3 This test method applies only to single, non-fluorescent
4. Summary of Test Method
pigmented colors and black ink systems for which there is a
4.1 A standard and unknown samples are each reduced to
reference standard containing a pigment of the identical color
the same concentration in a white tinting base then dispersed
index name and number.
on a paint shaker.
1.4 The procedure in this test method specifies placing
4.2 The dispersed samples are transferred to cuvettes for
tinted samples in a cuvette for spectrophotometric measure-
reflectance measurements on a spectrophotometer. Hue and
ments. The use of thick wet drawdowns as in Test Methods
strength relative to the standard tint are computed.
D2066 are inappropriate due to severe floating problems with
aqueous systems.
NOTE 1—The hue readings indicate the closeness of the unknown
sample to that of the standard.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 Tinting strength is an essential property of printing ink
priate safety and health practices and determine the applica-
dispersions. Although results on bulk tints do not guarantee
bility of regulatory limitations.
equivalency of dry printed films, they provide useful param-
2. Referenced Documents
eters for quality control of production batches of bases and
finished inks. Test results may also be used for color matching
2.1 ASTM Standards:
purposes.
D2066 Test Methods for Relative Tinting Strength of
Paste-Type Printing Ink Dispersions
6. Apparatus
D2244 Test Method for Calculation of Color Differences
6.1 GlassJars,capacityapprox.64g,33mmindiameterby
from Instrumentally Measured Color Coordinates
70 mm in height, with screw cap lids.
E691 Practice for Conducting an Interlaboratory Study to
6.2 Paint Shaker.
Determine the Precision of a Test Method
6.3 Spectrophotometer, with small area view (10-mm aper-
E1331 Test Method for Reflectance Factor and Color by
ture,diffuse/8°geometry)andwithacomputerandsoftwareto
Spectrophotometer Using Hemispherical Geometry
measure reflectance factor, calculate color differences by
E1347 Test Method for Color and Color-Difference Mea-
CIELAB 1976 equation. Tinting strength is calculated by a
surement by Tristimulus (Filter) Colorimetry
Kubelka-Monk equation transformed from the lowest tristimu-
lus value.Alternate instrumentation and software may be used
by agreement between producer and user, or different plant
This specification is under the jurisdiction of ASTM CommitteeD1on Paint
locations.
andRelatedCoatings,Materials,andApplications,andisthedirectresponsibilityof
Subcommittee D01.56 on Printing Inks.
6.4 Disposable Cuvettes, 10 mm in diameter, with at least
Current edition approved March 10, 2000. Published May 2000.
one optically true face.
Annual Book of ASTM Standards, Vol 06.02.
6.5 Disposable Pipettes 7-mL capacity, 3.5-mL bulb draw
Annual Book of ASTM Standards, Vol 06.01.
Annual Book of ASTM Standards, Vol 14.02. or suitable substitute.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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.
D6531
6.6 Balance, capacity 100 g, accurate to 10 mg, preferably 10.2 Referring to the manual of the software that is being
1 mg. used, set the computer to measure the reflectance of the
6.7 Black Electrical Tape. standard sample.
6.8 Black Cover, 90 mm in diameter such as 1-lb ink can, 10.3 Remove port cover and center an empty cuvette over
with interior painted flat black. the port with the optically true side facing the light source.
6.9 Ink Knives, small. Tape it in place using the black electrical tape.
6.10 Medicine Droppers. 10.4 Open the tint of standard sample and stir it with a
disposable pipet to insure homogeneity. Fill the pipet with the
7. Materials
tint.
7.1 Standard Ink or Base—The standard should be 100%
10.5 Touch the tip of the pipet to the inside surface of the
intended strength of the same pigmentation and similar in
cuvette that the spectrophotometer will read, and fill the
viscosity to the unknown sample.
cuvette to above the level of the spectrophotometer port in one
7.2 White Tinting Base, compatible with and of a viscosity
continuous motion. If it is not, the specimen will not read
similar to samples being tested.
properly.
10.6 Attach the port cover to the front of the spectropho-
8. Sampling
tometer and place the black cover over the cuvette on the port.
8.1 Carefully select a sample that is free of skin and other
10.7 Take reflectance factor readings of the standard tint at
contamination.Theminimumsamplepertestis1.0gofink,or
spectral measurements of 20 nm or smaller intervals.
0.5 g of base.
10.8 Remove cuvette from the sample port.
8.2 When ready to conduct the test, remove enough sample
10.9 Repeat 10.1-10.9 with the unknown tint sample.
for the test then reseal the container.
10.10 Alternatively, measure the CIE tristimulus values of
thespecimenonaspectrophotometerortristimuluscolorimeter
9. Preparation of Tints
in accordance with Test Method E1331,
...