Start Here November '21

Issue link:

Contents of this Issue


Page 38 of 102

34 S T A R T H E R E 2 0 2 1 much movement during the stroke process and can cause the ink to smear. A loose screen can also cause issues with registration when using multiple screens and result in blurry or jagged edges. Be sure to use the correct mesh size (larger for the underbase and smaller for a highlight color). Typically, I prefer a 110 mesh for the underbase white and a 160 mesh for a highlight white. Some use a 160 mesh as the base white and then a 230 mesh for the highlight white for highly detailed prints. Emulsion Coating Next, let's examine the emulsion. Sufficient emulsion coverage is crucial to obtaining an opaque, crisp print. Proper emulsion coverage is measured in EOM (emulsion over mesh) and should be around +/- 20%. Be sure to coat the underside (shirt side) of the screen thicker than the ink side. A thicker emulsion coating acts like a stencil wall that allows the ink to only go where it's supposed to, like a gasket. A thinner emulsion coating may not block ink as effectively, letting ink meander into pockets caused by the mesh texture. The resulting print image may show messy edges or smearing. Squeegee Hardness The squeegee is an excellent tool for controlling the amount of ink deposited onto the garment — a softer squeegee deposits more ink than a harder squeegee. To deposit a good amount of ink and thus increase the opacity of the resulting print, I recom- mend using a 65/70 durometer (medium) squeegee for both the underbase and the highlight white print. Dense Film Another critical aspect of achieving a crisp and clean print is the film. The artwork should appear as black as possible. When you hold the film up to a strong light, does it show through the dark, positive areas? If it does, your image may not translate well onto the screen. Be sure to start with a film that shows the design as opaque as possible. Similarly, the "clear" part of the film should be very clear and translucent instead of milky (such as vellum). This is especially crucial when working with detailed artwork. Heated Platens After the screens are mounted, and squeegees prepared, warm up the platens for about 5-10 minutes before printing. This is important as the heated platens improve the adhesion quality of the platen adhesive and can help make the ink flow better. Mat-Down/Flattening Screen Another "tool" is a mat-down/flattening screen, used right after the underbase print is exposed to the flash. The mat-down screen Another "tool" you can use for crisp, white prints is a mat-down/flattening screen. Used right after the underbase print is exposed to the flash, the mat-down screen "irons" the still-hot ink and pushes down fabric fibers, creating a smooth print. Ink is usually the most consistent part of the equation but is blamed for 90% of the problems.

Articles in this issue

Links on this page

view archives of GRAPHICS PRO - Start Here November '21