Proper screen exposure must take many factors into account –
the emulsion type, coating thickness, exposure unit, etc. As a general guideline for the different emulsion
types (diazo, dual cure, and photopolymer) use these times as a reference.
Photopolymer – These are typically the fastest
exposing emulsions, with many exposing correctly from 30-50 seconds. The shortest times can be seen when using a
newer LED-type exposure unit.
Dual Cure – If you have established a good exposure
time with photopolymer emulsions, you can typically add 90 seconds (1.5
minutes) to that time for most dual cure emulsions.
Diazo - If you have established a good exposure time
with photopolymer emulsions, you can typically add 210 seconds (3.5
minutes) to that time for most diazo emulsions.
These times will depend heavily on your exposure unit and
should only be considered as a starting point.