This overview discusses halftone styles and how to match them to the designs you print.
Art that works well with traditional halftones
The majority of screen printers who print halftones use traditional dots that have an angle and a density to them. They are created from common RIP software quickly and they tend to work well on most graphics with a few exceptions. The artwork that works the best with traditional halftones is artwork that has smooth gradients in it with blended colors that flow gently from one color to another. A soft, airbrushed image or a design with a lot of subtle effects works particularly well with this style of halftone because the shrinking dots can emulate the slow fading of one color into another color or the background of the garment (Figure 2).
Artwork that has a lot of realistic or photographic imagery is ideal for traditional halftones and these styles of dots can represent the delicate transitions needed for photographic reproduction the best out of the current halftone methods while using the least amount of screens and inks. The traditional dot’s flexibility and overall wide range of use make it a clear choice for the most popular halftone style in screen-printing shops. A close look at these dots shows how they merge together when then blend past 50% density (Figure 3).
The visual drawbacks to traditional halftones are fewer compared to some of the other types, but they are important to the screen printer because they directly relate to specific problems that can occur on press. Because these halftones shrink with size when they are reproducing a lower density, there is a fall-off point where the dots will simply not show up on the screen. This level depends upon several factors, but common things that dictate the fall-off point are the density and method of the film or image that exposes on the screen (CTS, computer-to-screen imaging machines are the best at controlling fall-off points) and what the actual screen mesh is. A lower screen mesh has bigger threads and will commonly block the reproduction of really small dots. A typical fall off density where dot exposure stops on the screen is around 8-12% for film-based exposure systems and 4-5% for CTS systems.
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