Check your Laser Printer. Is it set on the darkest setting. Go to “My Computer” – “Control Panel” Printers”. Some months ago we introduced a blackening Art spray. Which is used by spraying over your Vellum printed Artwork to make the black of the art blacker. This helps block out light in the art area of the vellum during exposure making for a quicker wash out time. It’s not absolutely necessary but helps the process. If you have bad water pressure this may help get a faster wash out.
Clean your Letralite’s Acrylic cylinder regularly with an Acrylic polish such as our McGuires brand. This keeps the Acrylic clear and clean and keeps your exposure time correct by preventing clouding of the cylinder. 3,4,5mil resist is exposed through the letralite for 30 seconds. 6,9mill is exposed for 45 seconds. Do not over expose. When exposing Vellum artwork you do get some light getting through the black as it is not a true opaque, So if you overexpose you’ll get more light in the wash away area making it take longer to wash out, which may cause excessive water on the resist during washout creating a soggy resist which will not give you the best quality.
Make sure you do not expose the resist to natural sunlight before you have washed it out. This will ruin the resist. Make sure passing windows are covered up OR buy an Attache bag to slip the exposed resist’s into for transporting to the washout room. When washing large areas always lay the finest detail at the top of the wash out board. DO NOT WASH YOUR FILM OUTSIDE IN SUNLIGHT.