So if you change your set up at all you might need to re-do the test. With every variable the result will be different. When you have done this and found the time that washes out perfectly (it should almost fall out) but all the detail is there, your edges are nice and crisp and the emulsion does not feel slimey, then this is YOUR EXPOSURE TIME! You can dial this in further, down to 10 second increments if you want. If it looks like your in between say 12 & 13 minutes. You'll find that some wash out too easily, some don't wash out at all but wait. So you've now got a screen with 10 different levels of exposure. When the timer gets to 15 minutes, slide the card down and allow the 15 minutes band to start getting exposed.Įvery minute move the card down until your last band is exposing, it should have 11 minutes to run at this point Cover everything apart from the 16 minutes band. Set your timer for 16 minutes counting down. Hopefully by now you can see where this is going! In this example we have put the card under the glass, you can also put the card on top of the glass if its easier for you.Īs we're testing from 16 -11 minutes, on the screen, give each inch mark it's own unit of time, starting at 16 minutes, working down to 11 minutes. Place your transparency on the screen as normal, so it fits your timing marks. We will use the card to allow part of the screen to be exposed for longer than others. The idea is that we are going to cover the screen with something that will not let light through, a large piece of black card works well, as you can manoeuvre this under the piece of glass. You could use masking tape and mark the tape if you don't want to mark the screen. Take a screen, mark on the frame, on the side you'll have the transparency, (print side) a line every inch. But we'll test from 16-11 minutes, because we're not totally sure and want to make sure we find out! By testing above and below your estimate you should find the sweet spot. In this example, we are set up with our Exposure kit and we're going to say that we estimate the exposure time to be about 13 minutes. If you need a bit of guidance on this, drop us a line and we'll try and suggest your best starting points.

If there are manufacturers guidelines on light brightness or power and distance from the screen, follow them, it will give you a starting point. So your overall exposure time will be different to others depending on how close your light is to the screen, how powerful your light is and what brand and type of emulsion you are using. If you're good on the above, let's carry on! The screen is correctly coated with emulsion and is completely dry. This way the glass weighs the transparency down and the foam supports the screen. Place your foam block one side, thin glass the other works best. The transparency is flat and tight to the screen. Read our guide to making great art work for transparencies. Hold it up to a light, if its not blocking the light, it won't work. Get your exposure set up ready, following any instructions or advice that come with it.Įxposures are best done either under a safe light, such as a yellow light or UV blocking filters, or if doing at home a dimly lit room is best with no major light sources that might fog your screen. Doing a step test and by checking the key points below, you'll find your perfect exposure time, for your set up, your environment and the equipment you have. Exposing screens using Photo Emulsion can feel tough, every set up is different and it's easy to miss something.

Large photo emulsion screen printing