Stand back and see what you can do to organize your shop processes.
Establishing process practices
To make rapid headway in standardizing your screen-printing process, first establish clear process practices for each department and put these into an internal manual for each area. Divide the sections into Art, Screens, Setup, Printing, etc. This new manual will help to create an environment where the specific tasks can be isolated and improved in the future.
The next stage is to create printed tests to show the current level of detail and printing capacity for improving detail based on the results. The easiest thing is to first go through and test print a gradient selection on your main mesh types using a specific pattern that is the most common for your shop (Figure 1). You can then assess the current print quality that a typical halftone gradient possesses and make determinations on necessary adjustments to reach optimum print quality.
An important point here is that the tests suggested in this article are for garment screen printing using plastisol ink. A typical print with plastisol ink will maintain the highest quality with the lowest level of printing pressure that releases the ink from the screen stencil onto the garment. In a water-based or solvent-based print, the pressure may need to be considered differently, depending upon the finished product. For water-based inks, more pressure may be necessary to ensure proper penetration into the fibers of the garment.
Once the basic dot-gradient print is done, then adjustments can be made to create optimal printing pressure. Depending on the visible results in the printed piece, adjustments may need to be made to the pressure, angle of the squeegee, ink viscosity, screen tension, and press, screen, or squeegee level. A very common result is to see tonal compression in the printed result of a halftone gradient (Figure 2). Tonal compression happens when the small dots that are created through a stencil halftone start to bleed together due to excessive printing pressure. The appearance of the printed gradient becomes overly dark and the 100-70% halftones blend together and look solid.
If a screen-printing shop is relatively new, it can be very helpful to have an experienced printer or industry veteran to help troubleshoot the process and quickly decide what variables should be adjusted to achieve the ideal print result.
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