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Prepress for Special-Effect Garment Printing

(December 2012) posted on Tue Jan 29, 2013

Decorating garments with special-effect inks can be a daunting task when you don’t have everything in place in prepress. These tips will assist you in building reliable and repeatable processes and procedures.


By Screen Printing's Solution Sourcebook

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As a general rule, you should select mesh with openings at least double the width of the largest particles in the ink. Ideally, you would use mesh with openings that are triple the width of the largest particles. Doing so would prevent multiple particles from wedging into openings and creating blockages in the mesh.

Mesh selection and stencil thickness are also important when you print an adhesive to which flock, glitter, or other particles with be affixed. Adhesive products must be printed thick enough on the substrate to hold the particles firmly in place, even during washing. For caviar beads, as an example, optimum adhesion occurs when at least half of each beads is embedded into the adhesive (Figure 2). Check with the manufacturers of the inks and coatings you use to find out about specifications for the adhesive thickness that best works with their specialty particles.

Mesh tension
Proper mesh tension is required for quality in any screen-printing job, but it takes on even greater importance when special-effects inks are concern. For example, high mesh tension is a must when working with high-density inks. High-density inks depend on thick layers of ink produced by thick stencils.

The combination of mesh and stencil is dynamic. Squeegee pressure causes flexing and stretching on press, and the greater the span from the edge of an opening in a thick stencil to the other, the greater the deflection of the mesh as it is brought into contact with the substrate. Deflection in large, open space leads to concave prints that have thick in deposits on the edges and thin areas in the centers (Figure 3). Highly tensioned mesh allows for lower off-contact and minimizes the deflection that causes concave prints.

Additional considerations
Thorough testing is the best way to determine compatibility between specialty inks, coatings, and additives. For example, your experiments may indicate that puff additives and metallic inks don’t play well together. Ink manufacturers can give you valuable insight about using special-effect inks properly, but trial and error will demonstrate how the inks behave with the artwork and equipment you use in your shop.

Generally speaking, less is more when it comes to special-effect inks. Sure, you can master the techniques necessary to put several types of specialty formulations to good use in a single design, but that doesn’t mean you should go crazy with lots of ink types in a single garment decoration. Using more than one specialty ink in a design can distract the consumer by creating a confusing field of visual and tactile effects that diminishes the overall impact of the design.

Finally, keep in mind that garments are washed and dried. Test your special-effect prints for washfastness and overall longevity after several wash/dry cycles. Be prepared to communicate the limitations of the special-effect designs to your customers, give them instructions about care and durability, and always focus on creative work and careful testing throughout your garment-printing workflow.

Excerpted from an article by Douglas Grigar, originally published in the June, 2004 edition of Screen Printing magazine. Images courtesy of Douglas Grigar.


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