T-shirt Screen Printing – How does it work? Part 1

T-shirt screen printing has stood the test of time as a viable non-digital print solution. While evrything is going digital, the process of screen printing has stayed the same for many, many years but in saying that, at the most professional level, it is an extremely technical and intricate process with very little margin for error. And while the process hasn’t changed too much the technology used in the consumables ie Inks etc. has opened new ways of achieving specialised finishes with much less work.

So how does screen printing work?

Well basically it is a process where an amount of ink is passed through an open area of a mesh and deposited onto a substrate which could be a t-shirt, paper, plastic, timber or basically any smooth surface.

Here are the details…

The major players as far as equipment you need are –

1) Screen
2) Ink
3) Squeegee
4) T-shirt

Screen – Traditionally the screen was made from silk stretched across a rectangular timber frame, hence the traditional name for the process, Silkscreening. These days we use a polyester mesh sometimes still stretched across timber, but mostly aluminium frames are used now. Timber tends to bow and twist witch cause the mesh to loose tension across the frame where as aluminium is very rigid while still being very light.

Ink – Inks can usually be separated into 3 different categories for t-shirt screen printing. Water Based, Plastisol and Specialty. Water based are exactly what they sound like and have a water base which make them easy to clean up and accessible to amateurs who want to try their hand at screenprinting. On lighter coloured tees they also soak right in to the pile of the t-shirt leaving a very soft feeling print that becomes part of the fabric. Plastisol inks are solvent based and require turps to clean up. They also need a higher temperature to set them. Plastisols leave a harder more rubbery feel print on the t-shirt but perform really well when printing on dark shirts. Specialty inks are your metallics, flocks, and puffs etc that give a special finish to the garment.

Squegee – Ever had your car window squeegee’d at the traffic lights? Well a screen printing squeegee acts in exactly the same manor just on a bigger and bulkier scale. It has a blade made from a plastic/rubber called Polyurethane and a timber or aluminium handle. Instead of removing water from a window it pulls the ink across the screen.

T-shirt – We all know what this is!! The final part to complete the puzzle (almost). Best to use cotton and if you are just starting out, light colour fabric.

Stay tuned for part 2 when we will look at the processes involved.