June '16

For the Business of Apparel Decorating

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2 0 1 6 J U N E P R I N T W E A R || 61 overlapping edges to make registering easier. However, trapping without flashing in-between will cause your water-based col- ors to mix where they overlap. Most of the printing done with water-based inks will be printed wet-on-wet, so you will flash much less often; possibly not at all. When design- ing for water-based printing, you will need to be mindful of this and avoid trapping when preparing your separations. MAKING A SCREEN FOR WATER- BASED PRINTING One of the first steps in preparing a screen for water-based printing is to choose the right mesh for your ink. Since water-based inks are thinner than plastisol inks, you will need to choose a slightly higher mesh count to prevent the print from getting muddy. Base your mesh count decision on your image detail and the coverage area of your print. The larger the area and the less detail present in your design, the lower the mesh count. The higher the detail and smaller the coverage, the higher you can go in mesh count. In general, any mesh between 156 or 200 should be fine. As with any screen prep, don't skip degreasing. A degreaser removes any oils, dust, and dirt from the mesh, all of which can cause issues in the adhesion of your emulsion, such as pinholes and fish eyes. These issues are especially concerning when printing with water-based inks since the emulsion is already prone to break down faster. Starting with a properly degreased screen will help your stencil last longer. Unique to printing with water-based inks, it's also very important to choose a water- resistant emulsion to coat your screen. The truth is, all emulsion types are water-soluble at some level, but some more so than oth- ers. Using a water-resistant emulsion will help you to avoid premature emulsion breakdown, and, for those extra-long runs, there are additional steps you can take to fortify your emulsion to help prevent this. Once your screen has been exposed, you have the option to take an additional step of hardening it. You can do this a couple of ways. Firstly, you can put the screen back on the exposure unit and expose it again. This re-exposure process will help to harden any remaining soft emulsion. Do this after you have already washed out the image and your design is print-ready. Secondly, you can chemically harden it. To do this, spray a hardener onto the washed out and dried screen. Spread the hardener evenly over the emulsion and wipe the excess off with a rag. Then, let it dry. It will take time for the hardener and the emulsion to chemically bond. To get the best results, let it dry for at least 24 hours. Whether you use a hardener or just sim- ply post-expose with UV light, this step is important to create a screen that will last longer. The downside is that both of these steps make it more difficult to wash out the stencil during the reclaiming process. But, this is a small price to pay to prevent your screen from prematurely breaking down during the printing process. Opposite: Water-based printing is easy for beginners, but tran- sitioning from using plastisol ink can be tricky. (All images cour- tesy Ryonet) Below: When working with water-based inks, you'll need to use a water-resistant emulsion to coat your screens.

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