Screens arent completely washing out.

[Jesseacosta]

Hello!
Very new to screen printing, trying to make my first print using my own artwork. I made a film positive on a transparency at Office Depot, and they look really great. Super dark blacks. My pdfs I took them were 1200 dpi bitmap images, so they were real crisp.
At home, I am using a speedball 10x14 screen, their diazo emulsion kit, and a 500 watt Ulitech halogen lamp with the glass removed. I coated the screen, let them dry about five hours. I cut black foamcore board to stuff inside the frame, and used a black sheet behind it as well, laid down my image on the screen with glass on top. I burned the image 14" away for 12.5 minutes.
When I washed out the screen, there is still some image in there. and I really did some good scrubbing too. Ive attached a picture of the screen, and the output when I pulled a picture on paper. Some of the areas would not come out. Am I doing something wrong in my process?

[drew]

Are you putting any extra weight on the glass to get better positive contact? Im pretty new as well but it looks like the issue could be the film positive isn't pressed to the emulsion well enough. Just my opinion though, hope it helps

[Jesseacosta]

Ill try that, as well as doubling up the film positives. Ive been reading up my situation, and it might just be that the film isn't doing its job of protecting the areas that need to be washed out. According to everything I've read, washing out a screen should be easy, and if it's not, it's because it wasn't exposed right. Wish me luck, attempting again this evening.

[Catspit Productions]

You got it Jesseacosta! That is exactly it. A color copier transparency is not dense enough to do the job. Normally with those copy store transparencies people will double them up as you suggested. It will work for a lot of designs but for finer detail it may cause some detail lose.

For this design you should be able to double them up and you may want to trim off a few minutes in your exposure time. You want to use the least amount of time needed to make the emulsion harden while not affecting detail or the quality of the burn.

In your post image it appears there is some emulsion cured within the design area of the stencil. These are areas where the light was able to pass through the copier transparencies. Inkjet film positives are the best for the money because you can use black inks that have UV blocking abilities or you can run standard inks as “color rich” blacks by printing 100% CMYK instead of only K.

I know everyone has a budget so I offer small quantities of some decent inkjet film here:

http://www.catspitproductionsllc.com/in ... tives.html

It may not be the best solution financially for all situations but it allows you to buy at lower dollar amounts.