This overview discusses halftone styles and how to match them to the designs you print.
The biggest drawback to traditional halftone dots is that they tend to gain in size on the final screen print. The reasons for this can be a variety of art and production issues, but the most common are: loose screen mesh (requiring higher pressure to get the ink to release onto the shirt), dull squeegees, poor exposure or underexposure of the screens, high print pressure, improper separations or print order, and poor dot quality. When these issues combine in a production run, the halftone may quickly gain in density to where the original image becomes almost solid ink with a loss of detail and clarity. This is one of the most common issues facing printers who want to start printing four-color process or detailed simulated process screen prints on garments. First, the dot gain needs to be managed on press and then the separations can be created and fine-tuned. Doing it in any other way takes a lot longer to achieve higher quality with screen-printed reproduction.
The main difference between the index style of dot and the traditional is that the index style of dot using a frequency pattern to reproduce density of value (Figure 4). These styles of dots are all the same size and they vary in distance from one another to recreate the proper value in an image. One other noticeable difference in a stochastic dot is that it is a square shape that will fit together like a checker board when different colors blend together.
The best types of artwork for index dots
Many screen printers use only index dots to reproduce their halftones. A lot of reasons may motivate this choice but it is common in certain styles of artwork and printing because of its specific advantages. Artwork that works the best as an index dot has shorter gradients in it and may already have a texture or grain to the image.
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