Instructables

Step 3: Spread the Photo Emulsion onto the Screen

This is where all those scraps of cardboard come in handy. The backs of old notebooks work particularly well.

Read the instructions on the emulsion and activator bottles and follow them carefully to mix them together properly. Pour a little bit of the emulsion onto the screen and spread it as evenly as possible onto the screen. You have to coat both sides. You can scoop the excess back into the pot of emulsion. Don't put it on too thick. You need a thin coat, as even as possible, and on both sides. Try to avoid drips. Again, you don't have to be a perfectionist. Just do your best.

Once you've got the emulsion on there, put the screen in a darkish place to dry. Closets work pretty well. It doesn't have to be totally dark like a photo lab or anything. I like to point a fan at the screen to help it dry faster.

Once it's dry you're going to want to go straight on to the next step so that the emulsion doesn't get exposed and harden completely on your screen. You can touch the screen to feel if it is dry.

beebek2 years ago
Didnt found the emulsion like "Diazo Photo Emulsion". But found some kinda orange crystalline material. The shopkeeper told me that it is the stuff that screenprinter guyz asks for. But the shopkeeper guy dont know which chemical to mix the crystalline material with to prepare the emulsion. Dont wanna mess myself with mixing the chemicals....
Can somebody please post what kind of chemicals are used for making the photo emulsion !!
beebek beebek2 years ago
Yesterday I found out that the crystalline material was dichromate. Now what another chemical to mix with the dichromate....any Idea...??
murtaza1213 years ago
miss tracy i have one little problem we dont have emulsion in our country and its very expensive to import things rather we have some thing called alco (I hope i am spelling it right) and the sensitizer. the alco is a white paste (like white glue) the sensitizer an orangish sort of liquid. is it the same thing that u have described here ?
sa murtuza.. if u ur living in karachi pakistan then i can suggest u some places for all the material...
yeah tht wud be awsum where is it?
almateus7 years ago
it may be interesting to know that the "emulsion" is white glue with a dye (that´s why it may be green or blue) and the sensitizer is potassium dichromate (wash your hands after using, toxic). It is the same process as in the old photographic method with dichromate and gum, but it uses the glue to close the screen.
tnydul almateus3 years ago
The emulsion is just regular white glue with dye? and the sensitizer is just a potassium dichromate solution? Is there anything else to this? It seems like this should be easy enough to make on my own. Luckily I'm a chemistry teacher so I have the ability to order K2Cr2O7 easily enough.
almateus tnydul3 years ago
yes! I am a chemistry teacher too. I have done it with white glue and dichromate many times. The dichromate crosslinks the polymeric chains of the glue, making it insoluble. Cool project to work with the students, and they get to choose the design they want to put on the t-shirt.
lbrownlee3 years ago
I have just put my emulsion on my screens but that was like 2 hours ago and they are nowhere near dry! How long should they take! Help!
sbryer103 years ago
i just made my own screen using this method and its turned out well but from reading some comments im wondering wil this really turn out well? plus is it realy nesessary to coat the screen with emulsion both sides
Hal Newcome4 years ago
I must have used too much goo because my screen took a long time to dry. It stayed sticky for over an hour, until I pointed a fan at it. So, definitely use a fan. I also had some drips form that were harder to get rinsed out of my design. Everything worked out well in the end, though. Thanks for the instructions!
labo7 years ago
how to print with different colors?
tmillet labo5 years ago
1. Do all necessary steps until you get to the point where you have an image in your screen. 2. On the flat side of your screen (The side that will be placed on the shirt or whatever you are printing on) put tape on all parts of the image that you don't want printed yet. 3. Print your first color. 4. Wash the ink out of your screen and remove tape. 5. Now tape the places that you just printed. 6. Choose a second color and print it. Now, using this pocess you will have to guesstimate where to line it up, so it can be hard with a complicated image.
Hi! I'm so thankful that you've posted this tutorial! I did screenprinting in school and was considering purchasing a GOCCO for my wedding invites! However, I just couldn't bare spending $200 or more on a machine they don't even make anymore! Anywho, as it's been a while since I've done this, I have a couple of questions: 1. The emulsion, you let it dry for about a 1/2 hour. Then, once dry to touch, I can place my screen face-down (so that it's touching black fabric), place my transparency design on top of the screen (so that the text reads left to right, like normal), place glass on top. 2. So, when I set my screen and design in the sun, it dries the emulsion EVERYWHERE THE DESIGN IS NOT? Is that correct? 3. Then once the emulsion is hard, the area where my design is SHOULD WASH OFF... correct? Does the rest of the emulsion stay on the screen? I want to use this process for my wedding invites. My hope is to print them onto 100% recycled cardboard cd wallets. Not sure if I'll get them all done in one day sooooo, WILL THE SCREEN STAY AFTER SITTING IN THE SUN? Do i have to do anything to procure my screen to keep it "healthy" when I'm not using it? THANKS SO MUCH and your response will be greatly appreciated! x.o._x
Oh, an additional question: I'm reading that it's important to also have a bit of space between the screen and the surface you're printing on. I'm looking to print on Cardboard, do you have a recommended space? Is there something I could use? I hear screws in the four corners work well so you can adjust the height if needed. ANY SUGGESTIONS? THANKS!
Screws sound perfect to me. The space is especially more important when printing on paper. With fabric it seems to matter less.
You have understood everything perfectly. The screen will last for years and years. You have to use a solvent if you want the exposed emulsion to come off. Just keep the screen clean. Don't let any ink stay on it after printing.
First off, you are my personal hero for posting this. I'd have gone out and bought one of those $300 Yudu things if not for this instructable. I've seen on the Speedball instruction sheet and on some other instructables that you can use a 150W lightbulb or something to do the emulsion exposure indoors--what are your thoughts on that? (I've been stuck waiting for the weekends just to try and get good sun for the exposures, and I'm getting impatient to make more designs!) "slimguy379" says he uses that on his DIY for like 15-20 minutes, but then again, he also makes his own emulsion so it might not work the same as the Speedball stuff.
Ok I have just started looking into this and wonder if the process where you trace your design onto the screen and then paint with modge podge (excluding the areas where your design will be) will actually work. I do not have sunlight much at all here (Alaska Bush) and even if we did the screen would freeze within seconds. Is there another way to burn the design into it and another way to wash this off? I don't think using a hose outside would be wise for me. Any advice would be helpful.
I'm not experienced at burning a screen without sunlight, but a UV lamp ought to also work if you have one. There are some comments about burning the screen with artificial light. I was trying to do it with a halogen at one point, but that's not UV and I thought it was working because the sunlight coming in through the windows of my apartment was exposing the emulsion. I've done this process indoors in the winter in Boston. I burned the screen with sunlight coming in through the windows, and then I washed the screen in the bathtub with the shower head.
labo7 years ago
how many sensitizers mix with emulsion?
beeyalen7 years ago
i have emulsion that was sensitized a couple of weeks ago, and it worked fine. the other day i tried to use it, none of the emulsion washed out after being exposed. i'm thinking it might be one of the following: 1. I opened the bottle of emulsion in the light (only for a few seconds though) 2. I exposed my screen for too long 3. the emulsion is too old I'm thinking its #3. It was originally green, but has now turned blue, the same color as the part of my first screen that didn't wash off, and the same color I believe it was before I poured the sensitizer in. Could the emulsion be re-sensitized?
tracy_the_astonishing (author)  beeyalen7 years ago
Unfortunately, your emulsion is just too old. You'll have to dispose of it. Keeping the lid off the bottle for a few seconds didn't expose it too long. It just doesn't keep forever. It does keep longer if you put it in the fridge, though. About three or four months.
An4rkiss7 years ago
hello.. i have this emulsion which is blue color and it doesnt come with a sensitiver or activator that u mentioned.. can i coat the emulsion on the screen without sensitiver or activator? normally how long to wait it dry ?
tracy_the_astonishing (author)  An4rkiss7 years ago
You must go back to the store and buy the little bottle of sensitizer. it will not work without it. The sensitizer is yellow, so it turns the blue emulsion green. Without the sensitizer, your emulsion is useless.
kylew7 years ago
Tracy, How many screens are able to be coated with a 7oz bottle of emulsion?
tracy_the_astonishing (author)  kylew7 years ago
This completely depends on the size of the screens. There is no set rule.
hi.. how many hours do i need to wait to dry the emulsion?? i tried to let dry the emulsion on my screen for two hours and after it i stored it in a cabinet for 2 days before i decided to proceed to the next step(exposing to sunlight)..after 2 days, i heated the screen with my design in a 250watts bulb for 20 minutes but nothing happened.. the emulsion was too hard to be wahed up.. i wonder what could be the problem?? does leaving your screen with emulsion for 1 day would hardened it all that would possibly interrupt your work?? thanks a lot!
Oh no! I'm so sorry you lost your screen. I hope you don't feel too discouraged. You only have to let the screen dry for a half hour to an hour, usually. Until it is dry to the touch. Your screen ended up being fully exposed to light everywhere. (Over two days even a little bit of light will do that.) You need to do the steps from putting on the photo-sensitive emulsion through exposing it and washing it off all in one days' time. Washing it out can be the hardest part, I think. Once the screen is fully finished you can then wait to print as long as you want. I'll make some small changes in the instructable to make this more clear. I'm sorry that you had to have this frustrating experience.