Monday, 26 March 2012

Coating Your Screen

It took a while, but finally I am ready to start running some tests with the old screen printing set-up! I'll try not to drag this post out too much, but essentially it is about how to coat your screen with photo emulsion, ready for burning your images onto it.

Pictured above is a basic spray bottle that I picked up from a DIY store, and a bottle of degreaser. I diluted the degreaser 10 parts water to 1 part degreaser, as suggested on the bottle. I gave my screen a good dousing in the garden using the spray bottle and working the solution in with a brand new dustpan brush. Then I rinsed it well with a hose and left it to dry. (In the end I got the hairdryer out to finish it off. It's at times like this I appreciate the benefits of the drying cabinet at Uni!)

The point of degreaser is simply to make sure that you get rid of any dirt or oil that may be on your mesh, so no impurities will interfere with the photo emulsion and cause it to separate when applied.

Whilst my screen was drying, I activated my photo emulsion. It's really simple to do. You just shake up the little bottle of sensitizer with some water and mix it thoroughly into the emulsion, which changed from blue to green.

It is important that once you have activated the emulsion, you keep it out of the light as best you can. That isn't to say you need to use it in a darkroom, just ensure you replace the lid after use and ideally close blinds/turn off any lights when you are using it.

To coat your screen, you are going to need a coating trough slightly smaller than the width of your mesh. You can tape up the edges afterwards.

Fill the coating trough with emulsion. Don't be too stingy, as you can scrape what isn't used back into the emulsion pot afterwards.

Then, leaning your screen securely against a wall and starting from the bottom, put your trough to the mesh and tip it just enough for the emulsion to start spilling over the edge. In one smooth motion, drag the trough to the top of the screen, coating the mesh. It will take practice to get this right, but you can scrape away any drips with some scrap card.

If you layer the emulsion on too thickly, I can promise you it will be useless and you'll have to start all over again. If you think you've put a bit too much on, simply go up the screen again with the trough, skimming off and catching any excess.

Put your screen in a dark place to dry and scrape the leftover emulsion back into its pot. You've just successfully prepared your screen for exposing.

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