[This is a wrap up of a screen printing course I took with The Print Club London. It’s mainly so I can remember what to do next time I give it a go, but I hope you find it helpful too!]

I got my start in graphic design as a digital designer, working for the website arm of a magazine in London. On the job, I picked up the basics of print design, largely by shadowing a colleague.

I quickly realised how satisfying working in print can be. When I could actually hold my designs in my hands, I found that I felt much more of a connection to my work, and I began to appreciate the finer details. There’s something quite therapeutic about spawning something tangible, over designing a webpage that you can only share on screen.

During my time at this publishing company, I visited the print factory where the magazines were made, and learnt more about different printing techniques. But one method that I’ve always wanted to try is screen printing. I have at least four screen prints on the walls in my home, and I absolutely adore the styles that are possible using this very simple technique. So last week I called in a belated Christmas present from my wife Laura and took a two-day screen printing course at The Print Club, London.

Day 1

The first day was spent learning the basics of screen printing, a little history, and learning how to set up our pre-prepared artwork files ready for printing on day two.

I spent quite a long time deciding on what artwork to prepare for the course. We would be printing using two colours, and I was told to bring a laptop with a photoshop design and my two colours already separated.

My wife Laura is famous among our friends for accidentally swapping out the wrong word in a sentence, or getting phrases ever-so-slightly wrong, but close enough so that you understand what she means. Some of her highlights include…

“The Harlem Witch Trials.” “I’m just so asphyxiated by that picture on the wall over there.” “I couldn’t get a word in sideways.” “That smell is really feng shui for me.”

Using one of these phrases, along with an uncanny depiction of her I made using the website familyguyyourself.com, I made an A3 poster in shocking pink and black.

“That couldn’t be more further from the opposite.” — The final artwork in two colours.

I traced the character in Adobe Illustrator and added a paint splatter effect behind the text, then brought everything into Photoshop for some tweaks and colour separation.

Registration and trapping.

Our class of six was shown some real-world examples, which were mostly done by artists based at The Print Club. I was absolutely blown away by what is possible using only a few colours.

This piece by Steve Wilson, for instance, was printed using only three colours (cyan, magenta and yellow). Using combinations of ink layers, the most incredible effects can be created. The gradients here were made using halftone dots.

Another piece here, demonstrated by our class tutor Simon, shows two versions of the same screen print, using the same colours, only printed in different orders!

We were also shown what can go wrong during the printing process. The Print Club has a poster show each year called Blisters, which has some seriously high standards for acceptance. One of the main reasons a piece might not be accepted is due to the mis-alignment of the colour layers. This alignment is called registration.

If the registration is off by even a millimetre, meaning the colour layer on top of a previous layer isn’t lined up exactly, then parts of another colour, or even the white paper underneath can show through the cracks.

This was a problem for my artwork. The black layer would be printed on top of the pink. Anywhere the black layer touched the pink, like the eyelids or around Laura’s head would need to be lined up utterly perfectly, otherwise white strips would show through.

With this in mind, I added an extra millimetre of pink to the edges of the first layer. I couldn’t think of a quick way to do this in Photoshop, so I painstakingly painted this in with the brush tool.

This file had already been ‘bitmapped’. More on this below.

This process is called trapping. The last colour layer hides any mistakes, as long as that colour is dark enough to cover any previous layers. Trapping my artwork would prove crucial later on.

Halftones and 50% threshold.

Once my two colours were separated to layers in photoshop, the file needed to prepared for printing onto ‘positives’ which would be transferred to my screens later.

To make your artwork edges appear smoother, Photoshop does this really clever thing called anti-aliasing. This goes back to the early days of digital fonts, when typesetters needed to make really small pt sizes work on pixellated screens. What happens is in areas of contrasting colour, the pixel values are changed to a series of varying colours and shades, to give the appearance of a smooth edge.

In screen printing however, this is bad. We can only print using a solid colour, not shades. So each colour layer needs to be converted to a bitmap.

A bitmap file is perhaps the simplest form of image file there is. It consists of pixel values of either black or white. That’s it. When we use a bitmap file to make a screen, we either get colour, or no colour, which is exactly what we need.

In Photoshop, we start by removing all colour from the image by converting our file to grayscale (Image / Mode / Grayscale). Then we can change our file to a bitmap (Image / Mode / Bitmap).

In Photoshop we’ll usually get a pop-up message with a few options. With a solid colour, illustrated design, like my artwork, this part is easy. Using a 50% threshold, the artwork is easily converted into black and white pixels. My artwork started as a vector, so its contrasting areas were solid blocks.