Traditional silk screen printing, or serigraphy, is a method of transferring an image onto a substrate using a mesh stencil. When printing t shirts we use a stencil that’s made from a fine mesh, stretched over a rectangular frame. Parts of this mesh are then blocked out to form a stencil, and that stencil is placed directly onto a t shirt. Next, ink is pressed through the mesh onto a t shirt. The parts that aren’t blocked will seep ink onto the fabric and form the print.
Imagine for a second that the mesh stencil is a flour sifter, and you’ve glued over some of the holes in the sifter, so that flour only comes out of certain holes, this is exactly the same principle for traditional silk screen printing.
Each stencil can typically only hold 1 colour of ink, so if you have a colourful design you'll need a separate stencil for each colour in your design, and this is printed consecutively one after the other. This printing method is currently used commercially to print fabric, garments, glass and also superfine computer components like circuit boards. It can also be used to print artisan ceramics, paper, bottles and many other things too.