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Magnify Your Process to Multiply the Results

(December 2009) posted on Tue Nov 24, 2009

Using a loupe to check for errors makes for a good method of identifying flaws and making improvements in the printing process.

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By Thomas Trimingham

Check the screen printing process in the same order the design would follow through the production process. The focus review would check films, blank screen mesh, coated mesh, exposed mesh, and final print. This allows for insight on how one issue can transfer into another area to compound a problem that eventually leads to major printing concerns. The simple equipment needed for this type of magnified check are loupes that you often get for free from mesh or screen-printing suppliers. A 10x loupe will work fine though higher powered ones are available for those who print on flat stock and at higher resolutions than typical garment printing.

Reviewing the films
Films are the most critical portion of the process to examine because screens and print will never be any better than the detail that is captured and transferred from the original film positives. The primary thing with close-up film examination is to understand what you’re looking for and what may be problems. Start by creating a simple file that will create a film with a variety of edge qualities to it and several halftone line counts so that these can be reviewed first (Figure 1). The reason for this is a random piece of artwork may not have the right value range to show the dots clearly depending on the design.

Improving the film process through investigation with a loupe requires knowing what to look for. A simple diagram shows some common trouble spots in films (Figure 2).
The biggest issues with films that can be seen clearly with a loupe are edge quality and opacity. These areas can be difficult because they affect the exposure directly and show up as screen problems. It is best to catch defects at the film stage and then make corrections before they appear as ink on a garment.


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