Rushing the separation process can lead to disaster in production. Find out how to determine which approach represents the best mix of quality and speed for your shop.
You can also define and edges manually, if necessary, by using Photoshop’s smudge, eraser, and brush tools. Finally, depending upon the image, you can copy the adjusted layer, paste it, run the poster-edges filter on it, and then adjust the opacity and blend mode so that just the edges merge down and help to define the original. Different options may be used depending on the colors and graphics in the image. Running through the layer-blend modes using the arrow keys is a good step here (Figure 4).
Edge quality The definition of the edges in an image contributes to its overall resolution. Many photographs that are used for designs to be screen printed are just plopped into a layout in Photoshop. These images may suffer from poor definition or unclear transitions from one shape to another in the graphic.
Solutions to poor edge quality in designs are complex and can take many forms, such as redrawing parts of the graphic, resetting type on top of fuzzy letters, and adjusting resolution selectively. You can also improve edge definition in a photograph by drawing on top of the original artwork in an extra layer using a fine black line to cut out shapes and define edges in the original. This works so well in screen printing because the black line knocks out a hole in the underbase or other colors, which helps to control ink gain, and the black line makes for a clean look on a printed shirt and gives the eye a place to stop.
Testing separation speeds
How fast can a separation run and still maintain the quality needed on press? Let’s look at what happened when two test images were processed through three separation methods that should work as quality processes for reproduction in screen printing (Figure 5). The results for simulated process, index color, and four-color process followed a predictable pattern with a few interesting exceptions.
Each method of separation has its advantages and flaws. The tests proved that expected variables would appear on press. The results of the speed tests of the prepared artwork were reviewed for time that it took to achieve final separations, number of colors necessary, and other considerations related to production.
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