ASTM D7734/D7734M-13(2020)

3.1 When formulating printing inks and overprint varnishes that dry primarily by oxidation it is important to know the stay open time so that premature drying does not occur on the printing press rollers and other components.

3.2 The applied ink or OPV film used for testing is thicker than the film printed on the substrate and nominally represents the film on the printing press rollers.

1.1 This test method covers a manual procedure for determining the stay open time of oxidative drying printing inks and overprint varnishes by a finger transfer method. Open is defined as a wet ink/varnish film.

1.2 The amount of time required to reach the endpoint is recorded in hours.

1.3 Typical inks and overprint varnishes that dry by oxidation are oil based sheetfed offset, letterpress, and screen inks.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.6 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.