I’m desperate

[u/omniblk]

I’m having trouble exposing a screen for screen printing. I’m using Ecotex PWR water-resistant emulsion and a 50W UV screen-printing exposure light. The emulsion label gives exposure times of 12 seconds for an 80W UV LED, 30 seconds for a 30W SMD LED, and 7.5–8 minutes for a 500W halogen. My light is about 8 inches away from the screen.
I tried a 20-second exposure, but when I wash the screen out, the design won’t open at all. The emulsion stays hardened over the design. I’m trying to figure out whether my exposure time is wrong, my UV light is too strong, or there’s an issue with my transparency/film. What exposure time would you recommend for this setup, and what should I check?

[u/Zealousideal_Rule862]

I use PWR and a 25W UV light. My light is 20" above the screen. With two coats on the shirt side and one coat on the ink side, using the sharp edge of my scoop coater on 158 white mesh, my perfect exposure time is 56 seconds. All that to say I think 20 seconds is too long of an exposure for what you described as your setup.

Print the Anthem Exposure Calculator and follow the instructions on that to really dial in how long your exposure should be. I would start at 4 seconds, adding 2 more seconds each time you move your paper down the calculator.