No, you absolutely should not expose screen print emulsion to direct sunlight.
Sunlight is the Enemy of Screen Print Emulsion
When preparing screens for screen printing, photosensitive emulsion is applied to the screen mesh. This emulsion hardens when exposed to UV light. The sun is a strong source of UV light, which means exposing your coated screen to sunlight will cause the emulsion to harden prematurely and uncontrollably.
According to the provided reference, "Sunlight is your enemy!"
Why Avoid Sunlight?
Exposing your screen to sunlight before you are ready to expose your design will:
- Harden the emulsion, making it impossible to wash out the areas needed for your stencil.
- Ruin your screen, requiring you to strip the emulsion and start over.
- Lead to poor stencil quality, resulting in blurry or incomplete prints.
While you can work with coated screens under normal room light (away from uncovered windows), sunlight provides a level of UV intensity that will quickly expose and ruin the photosensitive emulsion.
Best Practices for Handling Coated Screens
- Apply emulsion in a dark or subdued light environment (like a room with low wattage bulbs or yellow 'safe' lights).
- Dry screens thoroughly in a dark place, like a drying cabinet or closet.
- Store screens in a dark location.
- Transport screens to your exposure unit and washout booth under normal room light, ensuring you avoid uncovered windows.
By following these guidelines, you protect your photosensitive emulsion and ensure successful screen preparation.
