Decoration - Outstanding Imprints
How To Screen Print With Gel Inks
Imprints that outshine the competition are easily within reach with clear gel ink. You can create a variety of effects from a "wet" finish to high-density to high-gloss. However, you must understand the nature of this medium to print successfully. Gel is very thick with high viscosity. Therefore, proper prep is required. "It must be stirred on a mixer prior to printing, and with long runs stirred again to lower the viscosity for it to print more easily through the screen," says Mary Poissant, marketing and sales for decorator Apple Imprints (asi/36553).
Gel ink itself is typically printed clear. It can enhance multicolor imprints when printed last as an overprint. Poissant recommends a limited use: "just certain highlighted areas, not as a whole overlay of the entire design." Applying gel ink over the entire imprint, she warns, "could result in too heavy of an ink deposit, particularly if the design is large."
A better choice, she suggests, is a single-color image with complete overlay. For example, look at the tone-on-tone imprint Apple created for Hunt Country Vineyards. "The print was first gone over in the art phase, taking out the small detail and making it a bold silhouette," Poissant explains. "What you see is two layers of clear gel on that design. The first was printed and flash-dried, and the next was printed over top for the thick look. (It could use the same screen.) The color of the shirt goes darker with the clear gel printed on it. No dark green was printed under the clear gel."
Be sure to follow these specific steps to print clear gel ink correctly.
Choose Screens With Ink Viscosity In Mind
"Screens need to be roller frames, 80 mesh at about 40-plus newtons," Poissant says. "This will open the mesh for easier flow of the high-viscosity gel ink. The emulsion needs to be capillary film type. The thicker you want the gel, the higher the capillary film. It comes in sheets of 100 microns all the way up to 700 microns. We used 300-micron film for our print."
Double the Printing
To make the final imprint of the Hunt Country logo really stand out, Apple printed it twice – both a regular print and flash print. "Shooting capillary film can be hard at times, and much harder when the microns go up," Poissant says. "Variance in exposure times and type of exposure unit will greatly affect your results. We use a NuArc 6 k lamp for our screens." The steps, she explains: "Print the first gel screen 300 micron 1/16-inch off contact, then flash-dry it. Let cool before the second print, then come back with second 300-micron screen at 1/8-inch off contact and print again."
Off-Contact Printing is Vital
"The 300-micron capillary film we used gives us the thickness we need for the thick gel look, but the screen can't be laying on top of the printing pallet. It has to be at least 1/16 of an inch off the printing pallet." She recommends a medium squeegee blade at a 45-degree angle, printing at a slow to medium speed.