Burning or exposing screens for screen printing can be a very difficult and frustrating step, especially if you don't know the proper time to expose your screens. Improper exposure times can cause numerous problems, including screens that break down on the press while you are printing or screens that will not wash out or develop after exposure.
Every brand and type of emulsion will have a different exposure time. There are many factors to consider when figuring the correct exposure time for your screens and emulsion. Factors such as your exposure unit (does it have LED or Fluorescent light bulbs?) - the color of mesh on your screens (are they white or yellow?) - whether or not there are halftones in your design (or are they solid spot colors?)- and last of all- (is your Emulsion Dual Cure or Photopolymer?) These are just a few of the factors to consider when figuring up your emulsion exposure time.
After you are armed with the right tools and education you can dial in a find the correct time and process to expose your screens.
The above videos- will show and explain emulsions, show some common screen exposure problems and the solutions to keep exposure great & screens that develop well.