ASTM D6531-24

1.1 This practice covers the procedure for determining the relative tinting strength of waterbased ink systems using a computer-aided spectrophotometer.

1.2 This practice is applicable to waterbased printing inks and bases to be used primarily in flexographic and gravure printing applications.

1.3 This practice 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 practice 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.