ASTM D4942-20

Standard Test Methods for Water Pickup of Lithographic Printing Inks and Vehicles in a Laboratory Mixer

SIGNIFICANCE AND USE
3.1 The lithographic printing process requires that some dampening solution be emulsified into the ink. These test methods provide a rapid means for determining water pickup under laboratory conditions. Test results may be useful for specification acceptance between the supplier and the customer.  
3.2 In order that results be comparable, the tests must be run at the same temperature and with the same type and quantity of liquid added prior to mixing.  
3.3 The emulsions obtained in these test methods are of larger particle size than those typically produced in printing nips. Because of these and other variables in the printing process, water pickup results do not by themselves predict lithographic printing performance.
SCOPE
1.1 These test methods cover two procedures for determining the amount of water picked up by lithographic printing inks in a laboratory mixer.  
1.2 Test Method A covers single-point water pickup; Test Method B covers the rate of water pickup. Both test methods are applicable to any printing ink and vehicle intended for the lithographic printing process.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 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.  
1.5 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

• Status: Published
• Publication Date: 31-May-2020
• ICS: 87.080 - Inks. Printing inks
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.56 - Printing Inks

Relations

• Replaces: ASTM D4942-11 - Standard Test Methods for Water Pickup of Lithographic Printing Inks and Vehicles in a Laboratory Mixer (Withdrawn 2020)
• Effective Date: 01-Jun-2020

Overview

ASTM D4942-20 is a globally recognized standard developed by ASTM International, specifying test methods for determining the water pickup of lithographic printing inks and vehicles using a laboratory mixer. The ability of printing inks to emulsify water is a critical aspect of the lithographic printing process, making these standardized procedures essential for both ink manufacturers and print service providers.

The standard outlines two distinct procedures: single-point water pickup (Test Method A) and rate of water pickup (Test Method B). Both methods provide a consistent, quantitative approach to evaluate the interaction of inks with water or fountain solution under controlled laboratory conditions. These test methods are vital for specification acceptance and quality control between suppliers and customers in the printing industry.

Key Topics

• Water Pickup Measurement: Defines how to determine the amount of water emulsified into lithographic inks during laboratory mixing, reflecting ink formulation performance.
• Test Method A (Single-Point Water Pickup): Assesses total water absorbed after a fixed mixing period using a volumetric technique.
• Test Method B (Rate of Water Pickup): Evaluates water uptake at multiple intervals over ten minutes, measured gravimetrically for a dynamic profile.
• Laboratory Conditions: Stresses the importance of maintaining constant temperature and standardized test parameters for reliable, comparable results.
• Interpretation of Results: Results indicate water acceptance characteristics but do not directly predict actual press performance due to differences in emulsion formation in real printing processes.
• Reporting Requirements: Specifies the minimum reporting items, including percentage of water pickup, mixing time, and details of the water or solution used.
• Precision and Reproducibility: Discusses repeatability within labs and reproducibility between labs, supporting quality assurance.

Applications

ASTM D4942-20 is widely utilized in the graphic arts and printing sectors to support:

• Quality Control: Enables ink manufacturers and end users to verify ink performance, ensuring compatibility with dampening systems in lithographic printing presses.
• Product Development and Evaluation: Provides rapid feedback for formulators developing new or modified lithographic inks and vehicles.
• Specification Acceptance: Serves as a benchmark in purchase agreements between ink suppliers and print companies, reducing disputation through objective test results.
• Process Optimization: Assists in troubleshooting production issues related to ink-water emulsion stability on press.
• Inter-laboratory Testing: Facilitates industry-wide consistency, allowing different organizations to compare results accurately when using the same standardized equipment and procedures.

Related Standards

• ASTM D6043: Standard Guide for Testing Printing Ink and Related Materials
• ASTM D4212: Standard Test Method for Viscosity by Dip-Type Viscosity Cups
• ISO 2834: Graphic technology - Laboratory preparation of test prints
• ISO 2846: Graphic technology - Colour and transparency of ink sets for four-colour printing

Keywords: lithographic printing inks, water pickup, laboratory mixer, ASTM D4942-20, ink emulsification, printing ink performance, quality control, fountain solution, printing industry standards.

Using ASTM D4942-20 ensures reliable and standardized assessment of water pickup properties of lithographic inks, supporting better product development, quality assurance, and clear communication across the printing supply chain.

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: D4942 − 20
Standard Test Methods for
Water Pickup of Lithographic Printing Inks and Vehicles in a
Laboratory Mixer
This standard is issued under the fixed designation D4942; 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 3. Significance and Use
1.1 These test methods cover two procedures for determin- 3.1 The lithographic printing process requires that some
ingtheamountofwaterpickedupbylithographicprintinginks dampening solution be emulsified into the ink. These test
in a laboratory mixer. methods provide a rapid means for determining water pickup
under laboratory conditions. Test results may be useful for
1.2 Test Method A covers single-point water pickup; Test
specification acceptance between the supplier and the cus-
Method B covers the rate of water pickup. Both test methods
tomer.
are applicable to any printing ink and vehicle intended for the
lithographic printing process. 3.2 In order that results be comparable, the tests must be run
at the same temperature and with the same type and quantity of
1.3 The values stated in SI units are to be regarded as
liquid added prior to mixing.
standard. No other units of measurement are included in this
standard. 3.3 The emulsions obtained in these test methods are of
larger particle size than those typically produced in printing
1.4 This standard does not purport to address all of the
nips. Because of these and other variables in the printing
safety concerns, if any, associated with its use. It is the
process, water pickup results do not by themselves predict
responsibility of the user of this standard to establish appro-
lithographic printing performance.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4. Apparatus
1.5 This international standard was developed in accor-
4.1 Laboratory Mixer, equipped with a stainless steel speci-
dance with internationally recognized principles on standard-
men bowl 83 mm wide and 88 mm high, mixer blades that
ization established in the Decision on Principles for the
rotate at 90 r/min, and a timing device.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.2 Balance, accurate to 0.1 g, 600-g capacity.
Barriers to Trade (TBT) Committee.
4.3 Palette knives, two.
2. Summary of Test Methods
4.4 Thermometer, quick response.
2.1 Thesetestmethodsutilizealaboratorymixerforbeating
4.5 pH Meter (optional).
water or other agreed upon fluid into the test ink.
4.6 Conductivity Meter (optional).
2.2 For single-point water pickup (Test Method A), 50 mL
4.7 Graduated Cylinder, 50 or 100-mL.
of water is normally added to 50 g of ink and mixed in for 5
min. The water picked up is determined from volumetric
5. Reagents and Materials
measurements of free water.
5.1 Water—Deionizedordistilledwater,preferably having a
2.3 Forrateofwaterpickup(TestMethodB),waterisadded
pH of 5.0 to 7.0 (100 to 200 mL per sample); alternatively,
to 50 g of ink in increments of 20 mL and mixed in for 1 min
fountain solution or other aqueous medium as agreed upon
or more over a cumulative time period totaling 10 min. The
between the supplier and the customer may be used.
water taken up by the ink after each mixing interval is
5.2 Cleanup Materials—Naptha and rags or tissues.
determined gravimetrically.
6. Test Specimen
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and are the direct
6.1 A minimum of 100 g is sufficient for two determina-
responsibility of Subcommittee D01.56 on Printing Inks.
tions. Before removing ink from the can, stir or otherwise
Current edition approved June 1, 2020. Published June 2020. Originally
ensure that the ink specimen is representative. Close the can
approved in 1989. Last previous edition approved in 2011 as D4942 – 11 which was
withdrawn January 2020 and reinstated in June 2020. DOI: 10.1520/D4942-20. and replace sealing tape immediately after each ink removal.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4942 − 20
7. Conditioning 8.11 Discard ink left in the bowl. Clean the bowl and the
mixer blades with tissue wetted with naphtha. Discard the
7.1 Condition the instrument, water, and ink samples in a
returned water and rinse the cylinder clean.
constant temperature room or bath, preferably at 23 6 1°C.
8.12 Repeat 8.3 through 8.10 with a second specimen of the
7.2 Prior to use, check the alignment of the mixer blades.
same ink.
With the power switch of the mixer in the off position, set the
clean bowl into the turntable and engage the locking pin firmly
9. Test Method B—Rate of Water Pickup (by
into the slot in the side of the turntable. Tilt the mixer head
Gravimetry)
back and insert the blades, marked left and right, into their
respective holders. Lower the mixer head. If the blades hit the 9.1 Program the counter for the first interval of the mixing
side or bottom of the bowl, return the instrument to the cycle.
manufacturer for realignment.
NOTE 3—A commonly used cycle is 1-min intervals (90 revolutions)
times ten determinations. Intervals need not be uniform, for example, 1, 2,
8. Test Method A—Single Point Water Pickup (by
3, 5, and 10 min (90 times 3 plus 180 plus 450 revolutions).
Volumetry)
9.2 Optional—Measure water properties in accordance with
8.1 Program the counter of the mixer for 5 min mixing time 8.2.
(450 revolutions).
9.3 Weigh or tare the clean dry mixing bowl and blades on
8.2 Optional—If the first run of the day, pour test water into the balance. Add 50 6 0.1 g of ink to the center of the bowl.
a beaker. Measure pH, conductivity, and temperature at the
9.4 Lock the bowl on the platform of the mixer. With the
beginning of testing.
mixer head raised, carefully insert the blades into their respec-
8.3 Weigh or tare the clean dry mixing bowl.Add 50 6 0.1 tive holders. If ink on one blade touches the upper parts of the
other blade or the side of the bowl, carefully remove the ink
g of the ink to the center of the bowl.
with two palette knives and transfer to the bottom of the bowl.
8.4 Pour 50 mL of water (from 8.2) into a graduated
Lower the mixer head.
cylinder. If the ink is expected to pick up more than 100 %
9.5 Pour 100 mL of water (from 8.2) into a beaker. Meter
water, use 100 mL of water. Adjust the volume to 60.5 mL.
out 20 mL and add to the bowl.
Add the entire contents to the bowl.
9.6 Press the counter reset button, making sure that the
8.5 With the mixer head tilted back insert the clean blades,
desired number of revolutions is displayed on the face of the
marked left and right, into their respective holders. Lock the
counter. Turn the mixer on. Examine the contents of the bowl
bowl on the turntable. Lower the mixer head. Press the counter
as mixing progresses. If all liquid disappears into the ink, add
reset button, making sure that 450 is displayed on the face of
more as needed to maintain a layer of excess water on the
the counter.
surface of the ink.
8.6 Turn the mixer on. Examine contents of the bowl as
mixing progresses. If 50 mL of water had been added and all NOTE 4—Few specimens will take up more than 20 mLof water within
a 1-min mixing interval. If a high-water pickup specimen is being run and
of it disappears into the ink, stop, discard the i
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