Im completely new to this and Im getting by using found/free tools and materials and yes I know Im being a bum but times are tough!
The latest problem Im encountering is that the edges from around the acetate are been exposed as a thin border on the screen.
As my resources are limited Ive being printing using an ink jet printer and in order to expose larger images Ive had to stick separate pages together. This is exposing a bunch of lines where the acetates meet. Im also using a 500 watt halogen floodlight hanging above it for 20 mins to expose, would this be refracting the light?
Possibly expose it for a bit longer? Sounds like the light is refracting a bit. I get this sometimes unless I use a large/strong exposure unit. Try and get larger transparencies so all you have to do is tape/blockout the outer edges.