Screen-printing: The photo-emulsion process

Foreword

I learnt this method of printing at a fantastic print studio in Aberdeeen called Peacock studios last summer. This article is a way for me to document my time there and to provide an outline of this process, for other people wanting to learn more about Screen printing. I’ve found online and youtube tutorials only get you so far without explaining the basics along the way, and they assume an awful lot about previous experience. I hope this explanation works for you!


Screen-printing: The photo-emulsion process

This method is a fantastic way to screen-print as it allows you to print very fine lines. I use an A2 silk screen with a mesh size of 120 TPI (Threads per inch) which gives good detail.

Step 1:

I cut the paper to size, and remove any imperfections in the paper with a razor blade (fiddly work!). Then I smooth the paper over any slight dents with the end of a bone folder (a very smooth piece of plastic) over a piece of tissue so it doesn’t damage the fancy paper.

prepping paper

Step 2:

Next, I coat the silk screen frame in a thin layer of green emulsion, then leave it to dry. You can do this by using a metal ‘trough’ (As seen in the photos) filled with the emulsion. Lift the side of the trough to the bottom of the screen and tilt it very slightly, until the emulsion hits the screen. In a fast, sweeping motion, pull the trough to the top of the screen, maintaining a steady pressure so the emulsion doesn’t leak everywhere.

Bare silk screen Emulsified screen
Step 3:

I then take my design, which has been printed onto a transparent film, and place it under the silk screen. Then it is exposed to a bright light in a dark room, or in a specialist machine (see below). The area around the image that is exposed to the light will harden, while the emulsion hidden under the black lines of the design can be washed away. This causes the silk screen to act like a stencil, and also means I can use the stencil multiple times. This is far better than using a paper or plastic stencil, which may disintegrate or distort after several uses.

Film Exposure
Step 4:

I take the frame to a washing bay, and wash away all the un-hardened emulsion to reveal the stencil. It is then left to dry.

Step 5:

The silk screen frame is then attached to a printing bed, and I add masking tape around the edge of the emulsion to ensure the surrounding mesh doesn’t get paint on it! The squeegee is then fixed in place (this is the tool that pulls paint over the stencil).

Prepping printing bed Printing bed

Part 2 coming out next Monday! Stay tuned.

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