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Post exposure image washes out of screen

Posted: Mon Oct 17, 2011 1:51 pm
by dude
Hello, This is my first screen printing expirience as well as my first forum.

My first attempt, all the holes were filled leaving no image :shock: . I used one coat of emulsion and exposed it for 10 minutes under a BBA NO.1 photoflood 250 watt bulb... 12" over screen. The emulsion was mixed 24 hours prior to this attempt.

My second attempt, the image came though clear after exposure but washed off when I rinsed it with a kitchen sink sprayer, luke warm :roll: . I put two coats of emulsion on my 10" by 14" screen, letting the first coat dry before applying the second then I let it sit over night. This was exposed for the same amount of time with the same bulb at the same height.

I used speedballs ultimate screen printing kit. The emulsion sat in a 75 deg. garage for 2 months prior to second attempt.

I am very excited to get this going. Any help is greatly appreciated.

Thank you,
dude 8)

Re: Post exposure image washes out of screen

Posted: Tue Oct 18, 2011 6:19 am
by tompaine
Approach this methodically:
Does the emulsion work? Leave some in the sun for a while and see if it washes out, or over-expose on your unit.
If it goes hard you're OK.
Work out your optimum exposure, there's a guide here: http://www.positivityltd.co.uk/Tutorial ... ation.html
Make sure everything is standarised, same distance, same coating thickness etc.
Put a coin on your screen, it will act as a good mask so if your positives are too weak you can isolate the cause.
Are you coating & drying in the dark/filtered light? You could be pre-exposing.
Let us know the results.

Re: Post exposure image washes out of screen

Posted: Tue Oct 18, 2011 6:52 pm
by dude
Thanks for the help, I will try the things you suggested and post my results as soon as I can.

Thank you,
dude 8)