ASTM D7734/D7734M-13

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 may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with 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 responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.