CMYK Films

Here you can discuss issues related to exposing screens for screen printing. This includes determining the exposure, light sources and washing out the stencil in the washout booth. Emulsion issues may also be addressed here.

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CarlREvans
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Joined: Thu Apr 06, 2017 6:51 am

CMYK Films

Post by CarlREvans »

Hey there, any help is appreciated.

I am attempting my first 4 color process print, and I have hit a snag. My screens are not washing out properly. I know that the screen for each color is supposed to overlap, in contrast to spot color which does not. It seems as though, it's "all or nothing" and the screens clear out where the image is darkest, but are burned in where the image is lighter.

Emulsion: Kiwo Polycol Multi-Tex Blue
Exposure: Single source Halogen, Vacum sealed exposure unit
Screen Mesh: 305
Film and screen:
Film
Film
1491487556400-472417912.jpg
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Catspit Productions
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Location: Phoenix, Arizona

Re: CMYK Films

Post by Catspit Productions »

It looks like an over exposure but I do not see any dot in the film really. CMYK needs to be done as a full halftone. The colors will not mix properly if you print them as spot colors on top of each other. CMYK uses halftone dots to mix and/or place the colored dots near one another.

So what I see here looks like an over exposure as far as film to screen but if there is no dot in this CMYK image, it will not work out properly.

If you do have dot in the film I cannot see then this is most certainly an over exposure. With fine halftones and such sometimes we need to under expose a bit using a very thin stencil on a higher mesh count. This video may help out in getting some detail off:

Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!

http://catspitscreenprintsupply.com/
http://www.youtube.com/user/CatspitProductions
CarlREvans
Posts: 2
Joined: Thu Apr 06, 2017 6:51 am

Re: CMYK Films

Post by CarlREvans »

Yeah, I moved exposure down from 10 seconds to 5 seconds, still washing out detail.

Do you have a video showing the method you use to wash out? I am worried I might be doing it wrong.

Above video was helpful, thank you.
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Catspit Productions
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Location: Phoenix, Arizona

Re: CMYK Films

Post by Catspit Productions »

Interesting. Perhaps there is something else going on. Maybe this video will help given your film positives are okay.

Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!

http://catspitscreenprintsupply.com/
http://www.youtube.com/user/CatspitProductions
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