After a screen has been burned, washed out, and dried it is nearly ready to go press. However, it still must get a final look through and prep. Because a burned screen is essentially a stencil to print ink with it is very important to make sure the screen does not have any imperfections. Imperfections in the screen could be anything from emulsion drying in the print area/not being fully washed out, detail lost within the design during the washing out process, and any “pinholes”. A pinhole is a small hole in the emulsion that will allow ink to come through the screen and thus be printed on a product where it shouldn’t. To fix a pinhole a chemical that acts like a fast drying emulsion called “blockout” can be painted over the problem using a small paint brush. If emulsion has dried in the print area or detail has been lost in the design during the washout process, then the screen will most likely need to be re-claimed and the design burned on a new screen.
In order to get the best overall performance out of a plastisol screen print ink one or multiple ink additives should be used. The most common screen print ink additives are: soft hand fashion base, stretch additive, puff, thickening powder, & viscosity reducer. Ink additives cost very little compared to the outcome of how a plastisol ink will perform on press and on the final product (opacity and feel).
When mixing an additive with an ink, it should be done by weight and it is very important to not add too much of an additive as it can create a chemical imbalance that will cause the ink to not have the ability to fully cure, which is the worst possible problem. So it's always a good idea to start at the lower end of the suggested % amount as it is easy to add more, but not really possible to remove what has already been mixed with ink. Always check the additive’s directions as far as how much % weight can be mixed with ink and use a high quality scale that can measure to the hundredths of a gram.
