Accessory to execute the Mottle test (Back trap or Print method) on the Amsterdam, AIC2-5, Global Standard Tester 2 or Global Standard Tester 3H
Mottling is the uneven appearance, mostly in solid areas: small dark and light areas appearing in the surface of paper (board) caused by ink, paper or presswork.
Mottle is influenced by many parameters: type of ink, colour sequence, construction of printing press, speed, rubber blanket and the damping water. The most important influence however is the type of paper. Variations in the surface characteristics as absorption and smoothness play an important role in the mottle and are caused by the production process and the components in the paper.
There can be three kinds of mottle:
• Back trap mottle: an uneven printing result, caused by uneven ink absorption of the paper.
• Water interference mottle: an uneven printing result, caused by insufficient and uneven water absorption of the paper, followed by uneven ink absorption.
• Ink trap mottle: an uneven printing result, caused by a wrong trapping of the ink in tack and/or viscosity and is also influenced by an uneven absorption of the ink by the paper.
The test be executed on the following IGT Printability testers:
For more information look at the test method information W57 Mottle (Back trap method) and W58 Mottle (Print method)