How Long Do I Expose My Screen For?

This is a question I get a lot.  Any my answer is, That depends.  Many things factor into the equation of how long to expose the screen for like, screen mesh, type and age of emulsion, type of lamps in the exposure unit, how old that lamps are, and the list goes on.  So what to do?  You need to do a step wedge test.  A step wedge test is basically exposing the screen for a few different times and seeing which time produced the best image on wash out.  There are a few ways to do this test.  The expensive way is to buy a test strip for $30 bucks which is a piece of transparency that has a gradient of darker shades.  The benefit of this test is you only have to expose once and the strip lets different levels of light hit the screen.

The cheap way to do a test wedge.  Take construction paper and do 4-5 different exposures.  Move the paper to expose more of the image each time.  At the end you will have 4-5 different exposure times.  Just pick the one that washes out the best and there ya go.

{ 9 comments }

Patrick

just got a new exposure unit.. had a fun time doing the wedge test.. that is the best/ efficient way to go.. most emulsion companies will give u them if you ask

steve

Good point Patrick.. I should have asked, I paid $30 for test strip from Ulano.

satchi

im just using 3 10 flourescent daylights and expose it for 5 mins.and it works fiine
im doing this for 3 years and its ok

chris

So glad to have found your blog. I’ve been exposing all my screens in the sun, counting slowly to 100. probably about 2 to 3 minutes. I use the speedball diazo emulsion. Creating an indoor system would probably be good. I will do some experimenting.

mike

just wondering if the 15 second exposure time you stated was a misprint.that seems realy fast.
thanks

steve

just built my exposer hopin to use it 2marrow ill let you guys know

Jonathan

If you purchase some emulsion and chemicals from Saati, they will probably give you a test strip if you ask. My sponsor sells Satti products. Nice post!

Denise

I have some artwork that is very light. Should I burn it at a longer time? As of right now I tried burning it for 50 seconds.

Westix

It seems like everyone has different exposure times that work best for them. Even when you have 2 screen printers with the same emulsion, equipment and screen mesh, I have seen guys use completely different exposure times and get great results.

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