Screen printing - how does it work?
A screen is created for every colour of each print so an image is first separated into its individual colour elements (usually using Photoshop). Once separated, each colour element of the design is changed to black and printed out onto separate sheets of film at actual print size.
Each screen comprises mesh stretched over a wooden or aluminium frame. The mesh is coated with a UV-sensitive emulsion and left overnight in the dark to dry.
The acetate is then taped to the front of a screen and the screen placed face-down onto a UV light box. The screen is then exposed to UV light for a short time. Where the UV hits the screen, the emulsion changes its composition and crosslinks it together. Where the design on the acetate prevents the UV light from reaching the emulsion on the screen it does not crosslink. After exposure the screen is washed and the non-exposed emulsion washes away, leaving a stencil of the design behind.
The screens are attached to the arms of our printing carousel and garments are attached to the platen boards underneath. A multicolour design requires multiple screens (one for each colour) but, after careful registration, the different colour prints from these screens should fit together perfectly to reproduce the original design.
A squeegee is then used to press ink through the mesh stencil onto the fabric. Prior to printing and after each colour the T-shirt must be heated under a heater to permanently dry or cure the ink to the fabric.
This movie was produced in August 2007 by Amin Musa in collaboration with Conway and Young.