Screen printing is a printing technique where a mesh screen is used to transfer ink onto a substrate, except in areas where there is a blocking stencil b. A squeegee is moved across the screen to fill the open mesh area with ink. Then a reverse stroke causes the screen to touch the substrate momentarily. This causes the ink to wet the substrate and be pulled out of the mesh screen leaving a image on the substrate One color is printed at a time, so several screens can be used to produce a multi-colored image or design.