Screen Printing

1. Setting Up


Recently I decided to get back into printmaking, and took the plunge by investing in a small amount of screen-printing equipment. I have been preparing a space in the back room of my generous uncle's house; today my freshly painted shelves were dry, and my table cut to size. I'm off to IKEA in a few hours to pick up some cheap trestle legs for the old boy, and a bracket for suspending my exposing light.
I thought it would be nice to document this set-up (and my preliminary test runs when I'm ready for them), and share my experience with anyone out there who's thinking of doing the same thing. Or, for that matter, anyone who is even mildly interested.
Pictured above:
  • Stencil Strip, Degreaser, and Ghost Remover
  • A cat mug with some stationary in it
  • 2 squeegees: 1 x 8" and 1 x 15"
  • Photo Emulsion and Sensitizer
  • An assortment of Daler Rowney System 3 acrylic paints
  • Daler Rowney System 3 screen printing medium
  • 2 x spray bottles
  • Mixing sticks
  • Screen tape
  • Ply wood 'tabletop': 1220mm x 1090mm x 18mm
Although I have experience with screen printing, I have never attempted it on anything other than a proper screen printing bed, with access to a giant exposure machine, drying unit and jet-wash.
Watch this space.
 

This promises to be the longest, picture-heavy blog post of my life (edit: not as long as I thought!). Well, depending on how much I can possibly say about drilling and screwing, which is what I have done over the few days to get my workspace near completion. The above picture shows my desk, which is basically the aforementioned tabletop paired with some simple trestle legs that I picked up from IKEA.


Next, I drilled some pilot holes and screwed my hinge clamps into the tabletop, ensuring they were far enough apart to hold the screen steady, and also far back enough to accommodate a larger frame in the future. The screens I have at the moment are 24" x 20", 3 with 140T mesh and 1 with 120T. I would have photographed them, but you'll see them later on when I start printing anyway. Plus, no biggy, they're just 4 seemingly identical frames!


My final task of today was to suspend a make-shift exposure light over my desk. The lamp is a basic security light(400W) picked up from a supermarket, and the bracket was extended by screwing a piece of wood into the top. The top of the bracket is about 34" from the desk surface, so cross your fingers with me and pray it will be the right distance away from the screen for exposing. (I have done a bit of research, so I am hopeful!)

.. And that's about it for today. I already have my first project lined up, but before I can begin I need to do a test run with the exposure light, and organise a few little bits that should be arriving in the post this week. Until then - au revoir! - and if you have any questions, pop them in the comment field.


2. Preparing & 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.


3. Exposing Your Screen



For my test exposure, I used an old piece of work with heavy line work. In photoshop, I added time markers, which will make sense when you see them in action.

Ideally I would have my image printed on acetate, but this can run quite expensive. A cost-effective way of doing it, and the method I have always used, is to print the artwork onto basic printer paper and oil it up to make the white transparent. I have used baby oil (because it smells nice!), but cooking oil works just as well. When the paper is fully coated, blot away all the excess oil using some scrap paper. Newspaper is fine, but be careful that the ink doesn't transfer.

Now, for exposing the image, my equipment was layered as follows:
1. A black foam base
2. My coated screen
3. My artwork, right-side-down
4. A sheet of glass

The black base is to stop the light from scattering, and the glass is to keep the artwork still, and close to the mesh. The board you can see in the image is what I used to cover each section of the artwork at 10 minute intervals, to gauge what exposure time is best. After 40 minutes, the screen was thoroughly rinsed down with a hose, to reveal the burnt-on artwork.


Turns out, for a 400watt security light, 10 minutes is quite enough!

5 comments:

  1. Hi Catherine, I stumbled upon your blog and am fascinated and delighted as I too am just gathering the bits and pieces of equipment to do some screen printing so your blog is really helpful, thank you! Emma.

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    Replies
    1. Hi Emma, I'm thrilled! It's good to know that someone is finding this useful, and even interesting. :)

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  2. hi, i have been researching diy screenprinting these past few months for my cartoons and found your post very intresting, im still learning before i take the plunge. i had not heard of the baby oil method of transferring the image, does this work as well as films positives? i only have crappy inkjet so this might be better for me, how did the screenprint turn out? anyway very inspiring stuff! thank you so much, phil

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  3. Hello Catherine!!

    I currently have a security light sitting on my desk waiting for this exact purpose. Did you fit a plug yourself?
    An electrician was worried about the safety of the whole thing so wouldn't fit a plug for me... I assume you haven't had any trouble with it?

    Thanks, Grace x

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    1. Hi Grace,

      My uncle wired the plug onto the security light. Bit naughty, but an easy job and I haven't had any trouble with it. Just make sure you don't leave it on unattended.

      Catherine

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