Screen printing is the process of pushing ink through a mesh screen onto fabric or other surfaces. Different patterns and art can be produced by using a blocking stencil on the mesh which stops ink passing through. Screen printing requires three tools, a mesh screen, a squeegee and ink. One colour is printed at a time so if there is more than one colour, then a new mesh frame and stencil is needed for each additional colour. Stencils can be hand cut, printed film & exposed or printed directly onto the mesh. Smaller print shops will manually use squeegees to push the ink through the screen & larger print shops will use fully automatic carousels with multiple arms, where once its set up it’s a matter of someone loading the garments onto the carousel & someone unloading the garments to run through the conveyor oven to cure the print.
Fabrics that are best suited to screen printing include cottons, silks, jerseys and polyester. Fabrics that have a flat property and will absorb ink evenly are best suited. Fabrics that have some thickness to them often don’t print as well as smooth thin fabrics like combed cotton. Some prints with very fine details & gradients that print well on a t.shirt won’t necessarily print well on a fleece hoodie for instance. The fabric will also play a part in the quality of the print. The less fuzz on a garment the better.
Screen-Printing produces vibrant, bright colours and is suited to large or small prints on the front or back of T-shirts, polos, hoodies etc.
There are a number of different inks for different effects including glitter, metallics, stretch, puff, discharge, glow in the dark to name a few. The most common ink for your standard print job is plastisol. Some jobs may combine multiple types of inks for various effects.
Darker colour polyester fabrics & Polyester blends require a special base (undercoat) to block the migration of the garment colour into the print. Once the garment has been through the oven this migration can happen immediately or over time.
This isn’t usually a problem on lighter colour polyester garments or lower polyester percentage such as an 80/20 Cotton/ Poly blends. Darker colours will still generally require a white base then the print colour even if the print colour is white.
Screen printing is most cost effective in larger volumes. Smaller print jobs may be better suited to other methods such as embroidery, Direct to garment (DTG) and transfers to name a few particularly if there is multiple colours .