Make your own Photo Emulsion

I found a great tutorial on Instructables for “true DIY guide to screen printing” that included instructions on making photo emulsion using a chemical called Potassium Dichromate (which I found at Kama Pigment in Montreal).

WARNING: Potassium Dichromate can kill you ‘n shit.

This is the cheapest photo emulsion you will ever find… and it works for fine detail artwork and on any screen mesh. But only with water based inks.

**this post gets so many visitors! it’s crazy!!**

UPDATED!! 2016

Definitely look at the tutorial on Instructables first, that guy offers lots of important information!! Read the comments there too…

This is my “converted to baking measurements” recipe. If you need help with conversions from oz to ml to cups, I use this conversion site.

Ingredients:

1/2 cup of PVA white craft or carpenters glue (water soluble)

1/2 teaspoon of potassium dichromate

3 teaspoons of warm water

White craft or carpenters PVA glue, I buy it at the dollar store or craft store. Any cheap water soluble glue will work. Carpenters glue has a slightly better bond, but it’s a little more expensive. 120ml of glue makes just enough to cover three medium/large size screens.

Potassium Dichromate can be purchased at speciality arts stores that carry supplies for wood staining, leather tanning, custom pigment paints, etc. I found mine at Kama Pigments in Montreal.

First of all, work in a dimly lit room (obviously not totally dark or you can’t see what you are doing, just don’t use an overhead light and not in direct sunlight you should be fine)

Wear gloves… try not to get this stuff on you, it is toxic as hell.

In a small plastic or glass container, put 3 teaspoons of warm water.

Add 1/2 teaspoon of Potassium Dichromate and stir until dissolved. (do not use these measuring utensils or containers for food or anything else afterwards!)

The Potassium Dichromate is sensitive to light only AFTER you add water, but I do keep mine in a airtight container that I covered with duct tape, just to keep it at max potency. The store where I bought it though just has it in clear plastic bags on a shelf. I bought a 1/4 pound bag of it for about 8 dollars over 5 years ago and it still hasn’t lost any strength that I can notice (and I’ve got enough left to last another few years!)

Add 1/2 cup of glue and stir well until consistent and no lumps etc…

Again, do this in a dimly lit room (no overhead light or sunlight)

Spread thin and even on your prepared screen with a squeegee, as you would regular photo emulsion, and allow to dry. The Instructable link has info for preparing screens and squeegees etc, and there is lots of other info out there for that so I won’t repeat it.

Exposure time!

Depends on your bulb, distance, size of the screen, image opaqueness, etc. This is a trial and error process you will have to experiment with your timings to get it right.

In the photo below I think I was using a 100 w bulb, and it’s definitely too close. Since then I’ve got a 250 w bulb suspended at least 2 feet above the screen and expose for about 12-14 minutes.

This is a pretty good article explaining all the different issues with determining your exposure timing.

OMG I made a video tutorial! Enjoy!

Cheerz and happy printing!

 

 

 

27 thoughts on “Make your own Photo Emulsion”

    1. Hi… the link to the Instructable is in my post there… but this is it http://www.instructables.com/id/STFL74AFL2BQOP6/

      fyi the recipe I’ve come to use is:

      1 & 1/2 tsp Potassium Dichromate
      1/4 c water

      mix together till crystals dissolve in water (do this in a very dim lit room)

      and add 1 & 1/4 cups of glue and mix well

      exposure time with 150 watt bulb 20″ above is about 30 min for 14″x17″ screen

      good luck and let me know how it goes! 🙂

  1. Thnx! ….Nice info!

    Are u still using this receipe? is it perfected after experimenting and do you care to share?

    Can you send me an example?

    1. definitely still using this. but not sure what you mean by an example? I updated the recipe in the post, that’s the one I use every time I make a new screen.

  2. Thanks for the great info!!
    Does it just wash off with water? Or do we use some sort of detergant? Is there a time frame to wash it off before it sticks on forever? And are the bulbs uv or just standard light bulbs?
    thanks again

    1. Hi… thanks for your comment 🙂 I generally keep my screens forever, but if you want to reclaim a screen you can use hot water (same method used to reclaim screens made with traditional emulsion) and bleach. Spray the screen both sides with some diluted bleach (can also use kitchen or bathroom cleaner), let it soak in a few minutes, then spray with hot water. Longer you’ve had the screen, harder it will be to remove.

    1. Regular emulsion remover is more/less diluted bleach. You can use this to reclaim the screen. Generally, I keep my screens forever. I tend to make my own screens and use cheap/free screen fabric, so I don’t have to worry about reclaiming it. But I have used this emulsion on commercial screens and reclaimed them for reuse.

  3. How much did you dilute the bleach when using it to reclaim your screen? Cleaners for emulsion are almost as expensive as the commercial emulsions!

    1. True! I try to avoid buying anything… bleach is cheap and don’t need much of it. When I clean a screen, usually spray it with bleach in a tub, and then fill up the water to cover the screen and let it soak for a while. Then spray it with pressure to clear away the glue. Often requires more than one soak/spray to fully clear the screen.

  4. Hi! Do you know if this would be food safe? I’m doing research and trying to find something I would be able to use to print on foods. Is this still toxic after it is dry?

    1. hmmm… that is a good question! After burning the image onto the screen, and you wash all the residual emulsion that wasn’t hardened by light away, leaving just enough to fill the weave in the screen mesh around the design… there really isn’t very much left, and it doesn’t come off onto the print, it stays on the screen. So if you were to print with something edible, like a food dye, it should just go through it without taking any emulsion with it. like a stencil. but I’m really not sure about how toxic it is, or how you could test it… probably safer to use a food grade ink jet ink printer system and transfer the design? or cut a stencil? you could get a vinyl stencil cut by machine and use a roller?

    1. yes it is wood glue or regular craft glue. I’ve used both. The wood glue seems to hold on a little better but basically the same.

  5. I use natural light how long wood it take to expos in sun light? also who sell Potassium Dichromate beside on line?

  6. Hi, I’ve been able to find 100grams of Potassium Dichromat online and was wondering how many screens roughly you think that could coat?

    1. If the emulsion on the screen is dry to the touch, it should expose and hold on. Possible you didn’t expose it long enough. Try a longer exposure. Could also be your potassium dichromate is a different concentration than mine? maybe add more to the next batch and try again.

Leave a Reply

Your email address will not be published. Required fields are marked *