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Discussion Starter · #1 ·
Hi there,
My students and I have been having an issue with shooting screens. It seems that areas with lots of detail get washed out, or seem blurry. The detail will not hold, and other areas where there are thin lines by themselves or small dots do not want to wash out at all. I suspect the vacuum seal on our exposure unit is not sealing properly, causing the acetate with image on it to be too far away from the mesh when exposed. Does this seem like it could be the answer? Any other ideas for troubleshooting the issue? I have fresh emulsion (Kiwocol Polyplus S) and fresh bulbs in my exposure unit.

Thanks in advance for any insights you might have!! This is for art school screen printing, not commercial BTW.

In the image you can see the area on the left is supposed to be a cross-hatch pattern, but the sharpness is not there. the line work in the center didn't want to wash out at all. The flats did fine.
Rectangle Wood Material property Tints and shades Flooring
 

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How are you creating the transparency? Perhaps it is not opaque enough. I presume these were hand inked rather than computer printed. The large area may have worked better due to using a different tool/technique to apply the ink. Or as you suggest, maybe the art is not making good contact with the emulsion ... but I've had leaks in my unit before, and it still got the job done.
 

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a) use an exposure calculator to calculate the optima exposure time.
b) Ensure the printed side of the film is facing the emulsion.
c) Dye inks work better so use them if possible.
The last bit is something many people don't understand. The visible spectrum is irrelevant, and dye inks stop UV light much better than pigments.
If you have a Canon printer for example, the yellow dye will expose the screen better than the pigment based black.
 

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Discussion Starter · #4 ·
How are you creating the transparency? Perhaps it is not opaque enough. I presume these were hand inked rather than computer printed. The large area may have worked better due to using a different tool/technique to apply the ink. Or as you suggest, maybe the art is not making good contact with the emulsion ... but I've had leaks in my unit before, and it still got the job done.
I did hand ink these, but my students printing on canon printers onto transparency are having a similar issue, bit map patterns are completely washing out. But thank you, good to know the vacuum is probably not the culprit. I'll keep trying things.
 

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Discussion Starter · #5 ·
a) use an exposure calculator to calculate the optima exposure time.
b) Ensure the printed side of the film is facing the emulsion.
c) Dye inks work better so use them if possible.
The last bit is something many people don't understand. The visible spectrum is irrelevant, and dye inks stop UV light much better than pigments.
If you have a Canon printer for example, the yellow dye will expose the screen better than the pigment based black.
Thanks so much, I don't think we have the capability to use dye inks but I'll keep that in mind. I'll also check out the exposure calculator. Really appreciate it!
 
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