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Predicting and Managing Dot Gain

(December 2011) posted on Wed Jan 11, 2012

The advice shared here will help you anticipate the dot gain you’ll experience in your garment-printing work and minimize its ne

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By Screen Printing's Solution Sourcebook

Output resolution and mesh count can affect dot gain dramatically. The artist should make these decisions instead of the production staff, thereby controlling how much ink goes into each color. The output decision is the control over the frequency, and therefore the size, of the printed dot. Relatively small adjustments in dot-gain size can make a huge difference. If an artist picks a 42-line/in. halftone instead of a 55-line/in. halftone, it may seem like a small difference in the number of dots, but it represents thousands of dots in relatively small halftoned area.

Do more dots mean more detail? Not always. There is a struggle between the loss of tonal range at higher resolution and the retention of detail. A loss of tonal range commonly occurs at 65 lines/in. or above that may make any additional detail retention irrelevant if a printer has normal levels of dot gain. Most garment printers achieve the best results with halftones in the 40- to 55-line/in. range.

The artist needs to experience the cause and effect of dot gain to properly pick mesh counts for halftone artwork. This is a function of practice and thoughtful observation of previously printed pieces. Mesh selection can make or break a design. It dictates how much ink is picked up on successive screens and how much ink is there in the first place to spread. Selecting a mesh count that is high enough, but not too high, is critical for controlling dot gain. If the mesh count is too high, you will have a dull printed image, and you may even have difficulty getting opacity on a colored garment. The right mesh count will cover a printed area with a stable ink deposit that is bright, vibrant, and consistent. For detailed halftone prints, the mesh count can vary between 180-230 threads/in. for an underbase color and up to 180-355 threads/in. for overprinted colors.

The visual method of adjusting artwork for dot gain can be effective when it’s used with knowledge and experience. There is always the possibility of some unforeseen variables skewing the results, but just remember to record and isolate any unexpected results and you will profit from these problems as well. Estimating dot gain in Photoshop will save significant time and head off potential disasters on press if it is carefully done. Rather than fear dot gain and the problems it represents, take charge of the issue by evaluating the results of print production and then implement a system in prepress to compensate.


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