It’s a rush job and the press operator is on your case, the boss is on his case, and the customer is on the boss’s case. “We can’t do the job without screens! Where are they?”
You try to explain that you have pinholes and has anyone seen the bottle of block-out? And isn’t it Murphy’s law that the bottle of block-out was thrown out by the cleaners over the weekend because it looked old and had been sitting around for a long time?
In addition to always having block-out close at hand on the shelf with a “Do not touch my block-out” label on it, there are things to know about preventing pinholes. First of all, it’s almost never the fault of the emulsion — no decent emulsion manufacturer includes pinholes as an ingredient. It’s usually one of these things:
- mesh contamination
- poor degreasing techniques
- poor post-degreasing drying techniques
- dirty screen-making department
- improper preparation of emulsion
- particles in the emulsion or film
- coating speed
- trough design
- incomplete drying of the emulsion
- improper exposure
- contaminated exposure unit glass
- contaminated film positives
Take care of these basics and your &#!!*@! pinhole disasters should be few and far between. Blaming the emulsion is barking up the wrong tree — unless you bought some really cheap rubbish, But you’d never do that, would you?