Introduction: Basic DIY Woodglue Photoemulsion
These Instructions will lay bare the simplicity and flexibility of making photoemulsion for screenprinting. I feel that the Photoreactivity of emulsion spooks some beginners, who think something like a dark room is needed. Watch as i burn a screen with no regard for ambient lighting and the most minimal of materials.
Woodglue - I had the tail end of a bottle , like 1/4 cup or so
Potassium DiChromate - bought some about a year ago and haven't even used half. I dumped out what looked like about 1/4 gram ish.
water from the tap
squeegee
stretched screen
random clear sticker with a muppet drawn on in sharpie
scrubbie
Step 1: Mix Dichromate and Tapwater in a Little Vial
Added a few ml of water and shook until mostly dissolved.
Step 2: Dump and Shake
dump the vial of now orange water into the glue bottle. wear gloves and shake it well. at this point it becomes photosensitive so i moved to the dimly lit bathroom
Step 3: Coat the Screen
I just squirt it on and smooth both sided again and again. whatever scrapes off onto the squeegee is discarded until theres no holes or unevenness. Immediately i dried it with the hairdryer on cool for about five minutes. Keep it dim, once dry the emulsions sensitivity is at max.
Step 4: Make a Master
this one some dude drew and left at my house. Its just sharpie on clear vinyl
Step 5: Burn (exposure)
Stuck the sticker on, put a black board under and set it in the partial sun for 30-60 seconds. check after thirty you should see a marked color change. if not, give it more sun
Step 6: Washout
peel off the master and wet the screen. let it sit a couple minutes then rub it gently with fingertips under cold water . once the emulsion is washing out a short burst from the spray nozzle will clear it out. Be careful. after its clear let it cook in the sun to dry
Step 7: Print!
Thats it , It works!
Ammonium bichromate is even more sensitive and can be used with any polyvinyl acetate based glue.
From Wikipedia: "[...] potassium dichromate is carcinogenic and should be handled with gloves and appropriate health and safety protection. The compound is also corrosive and exposure may produce severe eye damage or blindness.[12] Human exposure further encompasses impaired fertility, heritable genetic damage and harm to unborn children."
"Aquatic organisms are especially vulnerable if exposed, and hence
responsible disposal according local environmental regulations is
advised."
thanks for the comments and catching that typo. It's dichromate, and I fixed it. Wear gloves, throw away the container used for mixing, and avoid contact of any kind with raw chemicals.
Please note: this Instructable says "chromate" in one place and "dichromate" in another. It should be "dichromate" according to the bottle in the first image.
Here I've been quietly gathering minimal screen printing ideas for two months, and everything you've uploaded in the last week has been everything I was looking for. Between this cheap photo-emulsion & your diy presses, I'm just waiting on supplies. Thanks a lot, I'll show you how it turns out!
cool