Can I use an enlarger or projector to make screens for printing t-shirts.

[GaryFlorida]

I would like to make screens for printing t-shirts by projecting an image onto the screen instead of contact printing it. This way I can use make whatever size I want from a single piece of small acetate film. I understand the limitation is that UV light is what is needed to cure the chemicals used to make the screen. Are there any UV bulbs or lamps that can be put into an enlarger or projector to accomplish this? Or would that even work?

Thanks
Gary

 

[Steve Smith]

Unfortunately, not much UV light will get past the lens. You could enlarge onto line film then contact print it.


Steve.

 

[GaryFlorida]

Unfortunately, not much UV light will get past the lens. You could enlarge onto line film then contact print it.


Steve.

Thanks Steve. Can you tell me more about line film? Sounds interesting.

 

[winger]

Would enlarging onto Arista lith film work? (I really want to try screen printing someday - just haven't had time and the projects list is already too long)

 

[removed account4]

gary

i just googled light sources for screen print emulsion and speedball has a chart you can work with
depending on the light source there are different exposure times. i also read use a 500 watt halogen light.
you can convert your artwork to a transparency by giving a copyshop your artwork / or file and asking them for a mylar or transparency of it
these don't really cost too much $$. coat half your screen with emulsion and do the equiv. of a test strip to figure out your exposure times.
speedball's home silkscreen diazo emulsion kit ( sold on amazon ) should have the light source chart with the kit.
i'd shy away from projecting with an enlarger/slide projector because it will take lots and lots of time compared with IDK 5 minutes with a bright source.

good luck !
john

 

[Steve Smith]

Thanks Steve. Can you tell me more about line film? Sounds interesting.

It's a very high contrast film. It will process as either black or clear depending on how much light it has received. To make a screen, the film is placed emulsion side towards the emulsion of the screen (underside) and is exposed to UV light. Areas of screen emulsion which received UV light will harden whereas anywhere which was shielded from UV light by the dark areas of the film will be able to be washed out to allow ink to pass through.

The film is a negative film so if you enlarge your image onto it and process it, you will have a negative. It will need to be contact printed to produce a positive again. Actually, if you are starting with a negative, the first run will create a positive so the contact printing isn't required.

Another way, out of the scope of this forum really, is to scan the negative, adjust the contrast so you have only black or white and get a company which specialises in producing artwork for the print industry to make the film for you.

Look up Agfa Orthochromatic film.

Would enlarging onto Arista lith film work?

It would if the original negative is of a high enough contrast.


Steve.

 

[Ian Grant]

There was an emulsion made for making silk screens by projection, I think from memory it was made by Rockland Colloids but it's 40 years since I dealt with them, they are still trading..

In theory there are a variety of ways to use a conventional emulsion and some have been used in practice for commercial applications. You could coat a screen with home made or commercial liquid emulsions and use the etch-bleach process, you'd need a high contrast negative though.

Ian