Screen Printing Forum

I've been using a piece of clear plastic that I got from Lowe's to keep the transparency in place during exposure. Is this step necessary? I was talking to a clerk at Dick Blick's and he said that the plastic can actually reflect light away from the screen, causing underexposure (which has been my problem). Is the glass or plastic necessary? Is the only point to hold the transparency in place? Could I just use tape instead?

Thanks!

Not only is the glass necessary, well, it's necessary. Stop getting screen print advice from an idiot at Dick whatever. WHile we're at it somebody please go burn down speedball. You need to use pressure with glass to keep the positive absolutely smashed against the screen. Any place where there is space between the positive and the emulsion or film will get light undercuttting it. A vacuum blanket is optimal but foam rubber you can get from an upholstery shop can be use along with glass and gravity to keep your positive in place. Your exposure problem might be because of poor quality positive. If your positive is not opaque enough light will shine right through it. Then you still need to consider light source, distance, temp, humidity, etc. There's a lot of variables that go into making a proper screen, the more you can control the more reliable your process will be.

Thanks for the reply! I just got a piece of clear plastic from Lowe's Hardware, would glass be better?

yes