Testing the Lithographic Behaviour of Printing Inks in Printing Presses and in the Laboratory

A special method to test printing inks in a sheetfed press equipped with a set of measuring instruments has been devised. This set consists of devices measuring the amount of water on a nonimage area, water and ink contents of the emulsion on an image area on the plate, as well as wet tack and emulsion film thickness on a form roller. Such print tests give an excellent evaluation, but are expensive, owing to the cost for operator payment and for stock purchase. Additionally, a new laboratory testing device using the same set of instruments, the Litho-Lab has been developed and presented. This testing device permits simulation of the procedure of emulsification of the dampening solution on a roller system. Several printing inks have been tested on a sheetfed press, as well as on the Litho-Lab. Although there is no ink flow, the Litho-Lab gives a lot of information and a good correlation with the behavior of inks in a production press.