To make rapid prototyping, I make my PCBs at home. I print the PCB tracks negative to normal A4 paper using laser printer so that I dont get stretching. Then place this paper on a film in a dark room and expose it to strong light for 1 second, develop the film and I get professional quality mask for uv exposure.
This is all for rapid prototyping for single layer and double layer boards without plate through holes.
In no way i can compete with comercial PCB makers and for production I send my gerber files away to fabricate pcbs with full silkscreen and coating.
However I tried to buy the film sheets today, but a supplier said they are out of them and told me to try a special thermal transparency paper colored blue for printing directly using laser printer without the trouble associated with developping and said the blue acts as a filter and produces very good quality dark patches and he uses it for comercial purposes.
I bought a box and will try it tommorrow.
Mahmood