Underbases For Light And Dark Shirts

Lets talk about underbases.  Every month we receive questions from our customers about whether they need to print an underbase and if so, which inks they should use.  Here’s Kieth Stevens, our Western Regional Sales Manager with some insight into this topic: "Underbases are used for many reasons:  On dark garments, white inks are used as an underbase to make the shirt background lighter in color so that the inks printed on top appear brighter.   As many of you have experienced, when printing a bright red on a black shirt without an underbase, for example, the resulting print of the red looks more like a muddy brown.  So a white underbase is used to obtain the actual tonal value of the original color intended.    On light- or lighter-colored garments, printing an underbase can actually improve washfastness/fibrillation control.  Here’s an example of what I mean: I have had many experiences were we printed an underbase on a particular design, such as a Disney^® Mickey Mouse image, everywhere except under the ears of old Mickey.  On one design in particular, the garment color was a bright fuchsia and the black ears were a large part of the design. Imagine our surprise when we found out that after washing, the black ears would have the fibers of the fuchsia showing through, but nowhere else on the print.   Naturally, we concluded that because the rest of the design had an underbase, in essence double the thickness of ink to hold the fibers back, only the black ears area had this problem.  So we added an underbase to the ears portion and saved the order.  Of course, this fibrillation issue may not occur with all T-shirts, but we were smart enough to do a wash-test before our large production run.  We didn’t save money on ink cost on the large order, but impressed our client with the quality.   (Incidentally, we also ended up adding a little suede additive to reduce the shine of the black). In another instance, we used a clear ink as an underbase (i.e. 3816 Sentri Clear) on white garments to not only improve the wash fastness/fibrillation but to also use it in areas of the design to actually create a slight gloss which the customer really liked.  For example, try using it on the tires of a hot rod image to give it that “just-detailed” look. Which inks are best-suited to use as an underbase?  This is a loaded question, as it really depends on your substrate.  For cotton fabrics, almost any white ink will do, although there are some that are brighter than others (i.e. International Coatings' 7033 or 7034 Ultra White).  For fabrics that tend to bleed (polyester or polyester blends), be sure to use a low-bleed white, such as International Coatings’ 711 or 7014 White, or 7041 Paramount White." For more on International Coatings’ line of white inks, go to our White Plastisols page on www.iccink.com.  Proceed to go to the Inks page from the Screen Print Plastisols drop-down, then choose White Plastisols.