![]() The point on your screen where the emulsion doesn’t wash away is the ideal exposure time for your emulsion. Continue this process until you’ve tested several times, then wash the image away. Pull the piece of cardboard back and expose for a minute longer. It can be helpful to test your emulsion’s exposure time: Using a piece of cardboard, cover a swatch on the screen and expose. Can you see through the black ink of the positive? You need to use a darker ink to create your positives. If you can’t see through the ink, try lengthening your exposure times. The two most common culprits for inadequate exposure are transparent positives or too short exposure times. First, hold your film positive up to the light. Fortunately, when stencils wash away, the problem is clear: Your screens haven’t been adequately exposed. Seeing your newly exposed stencils wash down the drain can be extremely frustrating. Knowing how to troubleshoot the most common exposure problems can help you nip these issues in the bud, helping you to avoid a great deal of frustration in your screen printing shop. Problems with exposure generally manifest during the washout process, through screens that won’t wash out well enough, emulsion that softens too much or images that develop blurred lines or pinholes during the washout process. For that reason, exposure problems can cause some of the most frustration in screen printing shops. Use Haze Remover 5230 to remove ink and haze residues, if necessary.Are your screens giving you problems? You know how important a great stencil is in creating a great screen print. Wash the screen with a forceful spray of water. Do not let the stencil remover dry on the screen. Screen Systems Biodegradable solvent 2500 or 2550 will remove almost all inks. STENCIL REMOVAL: Remove ink from the screen using a solvent. Use Speedball blockout thinned with equal parts water and apply with a spotting brush. Touchup Use excess emulsion and re-expose the screen. Apply Speedball blockout with a plastic applicator squeegee or 14 ply cardboard. Blot excess water from the printing side with unprinted newspaper stock.īLOCKOUT / TOUCHUP: Blockout Before drying and exposure, use excess emulsion from the coating step to cover the blockout area. Rinse both sides with a gentle spray until no soft emulsion is left on the squeegee side, and no foam or bubbles remain. ![]() Then spray the printing side forcefully until the image areas clear. WASHOUT: Wet both sides of the screen with a gentle spray of cold water. The optimum exposure is when the emulsion first reaches its maximum color density, and the edges of the positive do not "resolve." The squeegee side emulsion is hard, not soft or slimy. Use a dehumidifier in the drying area is strongly recommended, if possible.ĭETERMINE OPTIMAL EXPOSING TIME: Make a Step Wedge or use an Exposure Calculator Kit carried through to actual printing to determine your optimum exposure time. Under humid conditions, dry the coated screen with warm, filtered air up to 104° F. Additional coats can be applied to the print side to optimize definition.ĭRY THE SCREEN: Dry screens thoroughly in a horizontal position, printing side down, at room temperature in a dirt- and dust-free area. After each coating, rotate the screen 180°. ![]() Method 2: Apply two coats on the printing side, then two coats on the squeegee side, wet-on-wet. Apply one coat of emulsion to the printing side, then one coat on the squeegee side. The coater should be at least two inches shorter that the narrow width of your screen. ![]() Wait at least one hour for the emulsion to de-bubble.ĬOAT THE SCREEN: Use the rounded edge of a scoop coater to apply an even coat of emulsion in one pass. Stir with a clean, broad, flat plastic or stainless steel instrument until the emulsion is uniform in color. Pour the fully dissolved sensitizer into the emulsion. Dissolve the diazo sensitizer powder by adding lukewarm water up to the shoulder of the bottle. SENSITIZE THE EMULSION:Handle under yellow light. It increases the surface area of fabric for a better mechanical bond of the stencil, increasing printing run length. (Mechanical roughening is an option for new fabric that is not surface treated. FABRIC PREPERATION: Used or surface treated fabric need only be degreased using Screen Systems Degreaser 5505.
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