# photo emulsion issues



## hgArt (Nov 5, 2016)

Im having a lot of trouble with photo emulsion . I want to know how emulsion is suppose to feel/look like after its been exposed and washed off .Like are the exposed areas suppose to feel smooth or they have a textured feel ? My image shows up clearly after i expose, and it seems to wash off fine. I'm using speedball diazo emulsion (its green) and I'm exposing images with a Yudu machine unit . Im using a yellow 200 mesh screen . I don't know if I'm not washing the emulsion off properly , or if I'm not over/under exposing . Some areas are printing out fine where others are just not printing . I hope i made sense trying to explain my situation 
This is my drawing that I'm trying to screen print surreal eye drawing by hg-art on DeviantArt


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## Wig (Jul 8, 2014)

Sounds like you might be having the same issues I am. I expose my screen and the image appears to wash out fine but after it is dry you can see a sheen on portions of the washed out area, sort of a "ghosting" look. I have to take a wet rag and scrub the image area a little then blow dry it, sometimes more than once, to get the screen to work. That is the only solution I've come up with so far. There has to be a better emulsion to use out there but I don't know what it is. I've tried Green Galaxy Cryocoat from Ryonet and Ulano Orange. Both do the same thing.


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## sben763 (May 17, 2009)

Under exposure. To the OP you post problems with photo emulsion and then say your using Speedball Diazo which is dual cure and not photo emulsion. In your case under exposure is allowing the diazo to not fully cure. Expose longer and or use a thinner coat of emulsion if you have a thick coat of emulsion. 
@Wig under exposure also but the Ryonet which is a Saati product and the Ulano are photopolymer and tend to be temperamental to humidity. Having a dehumidifier and keeping humidity 35% will keep exposure times consistent. 

To both Search a step wedge test here or google. You can download and print. As long as you can print decent films IMO that's better then a exposure calculator although if you use a exposure calculator and then have a hard time washing out would indicate your films aren't blocking enough UV. If you pat dry the ink side after washing out and you get any emulsion color on paper towel from the image area then your under exposed. You can get dolor from the thicker edges from scoop coater. 

If your leaving water on or wiping it off can cause issues. I use a shop vac(never been used besides drying screens) in blow mode with crevice tool and blow off excessive water. Only takes a few seconds and help screen dry much faster.


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## sspllc (Nov 5, 2016)

Make sure your film positive is nice and opaque too. When you hold it up to the light you shouldn't be able to see light coming through the black areas.


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