There’s never been a better time to hop aboard the water-based inks train.
By Lon Winters
The lack of opacity may require multiple underbase techniques. It’s common to print a first-down clear or a low-opacity white base overprinted with a high-opacity white to create a smooth, white underbase with transitions. The less opaque white would be printed through a higher mesh, then flashed, with the more opaque white printed through a lower mesh count. Highlight whites are sometimes employed as well. The secondary underbase should include the brightest and whitest areas of the image. Many dark colors will overprint only on the first white. Additional screens may be required as dye blockers for polyester and blended fabrics. Transparent and fluorescent colors may require additional screens as well.
Jamie McCrae from Latitudes says, “Opacity is the big one for HSA. Choose wisely. Most plastisol printers are used to printing one to two screens of white and one screen per color. With HSA, it’s more like two to three screens of white and one to three screens of color – fluorescent colors being the worst.” We’ve seen that dynamic at Graphic Elephants. In order to get a fluorescent yellow on a black or red polyester shirt, the print sequence might be as complicated as this: Clear (to mat down fibers), flash, blocker (to control bleed), flash, blocker, flash, white, flash, white, flash, fluorescent color with white mixed in, flash, fluorescent yellow, flash, yellow.
The color mixing process for HSA and polyurethane hybrids will be familiar. Pigment percentage guidelines and a formula guide help in creating color matches. Most manufacturers provide RFU colors, though rarely is an ink ready to go straight from the bucket. Typically, inks require additives to combat in-screen dry time, washfastness, anticrocking, and/or lower curing temperatures for difficult fabrics. These and other additives are resourceful tools. HSA water-based inks and hybrids are easy to mix and store for future use.
Water-based inks can contain any number of additives and components including solvents to inhibit premature drying in the screen, assist in curing, and improve durability, among other things. These chemicals, combined with the water in the ink, can be extremely aggressive toward the stencil. Selecting the right stencil system is critical to producing durable, reclaimable screens for use with water-based inks.
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