You cannot take it out into normal lighting until you've burnt your design into the screen. Any emulsion exposed to UV rays will not wash out of the screen.

 

A quick flash of daylight isn't going to hurt too much but just keep it in a lightproof wrapper because it will start exposing and become difficult to wash-out.

 

You can actually coat your screen under normal room light, but away from uncovered windows. Dry and store in the dark. Again, you can take your screen to the exposure unit and to your washout under normal room light. But never by uncovered windows. Sunlight is your enemy!

 

You can actual coat your screen under normal room light, but away from uncovered windows. Dry and store in the dark. Again, you can take your screen to the exposure unit and to your washout under normal room light. But never by uncovered windows. Sunlight is your enemy!

I've coated every single one of my screens under normal room light, and it didn't hurt. Luckily, I don't have any windows in the back of the shop. I even wash my screens out under normal room light. I still get a perfect washout every time.

I just make sure not to over-do it..