Can you use discharge on light color shirts? Sure. Sometimes regular waterbased inks are better, but discharge can be used on light color shirts. Sometimes we use discharge without the activation powder in it on multi color prints on light color, just because you can print "wet on wet" which means you can print complicated shirts faster.
Discharge is a specialty ink used in screen printing. It results in very soft hand, showing the shirt's natural fiber instead of laying a thick layer of ink on top of the shirt, and can be printed as pure discharge or with pigments added so that the result is a colored discharge print. By itself, discharge ink removes the dye of the cotton fiber when it hits a certain temperature. It works with a variety of different brands and styles of t-shirts or other garments, with some styles and colors having stronger results than others.
Discharge printing can have various results in bleaching efficacy. In our experience, darker colors of Gildan and American Apparel shirts discharge well, while medium shade colors may not. Gildan colors that we have tried that discharge well include navy blue, black, olive, charcoal, chestnut, indigo, leaf, forest green, blue dusk and brown, as well as brown, slate, navy, asphalt and black in American Apparel, and many more colors in both. We have good experience with different colors and brands and their ability to discharge. It really depends on the specific dye used and results can vary within the same brand and color but in different sizes because sometimes a small shirt will be made in one country but medium in another country with slightly different dyes. It can be somewhat unpredictable so a little flexibility is good.
Shirt colors that don't discharge very brightly can still be used for discharge printing. If someone wants a white print with discharge qualities of minimal hand, white pigmented discharge can be used to acheive a bright white on garments that don't discharge 100% well. One layer of white pigmented discharge can have the same visual result as two layers of normal, opaque white ink but without the heavy hand or any of the difficulties in printing that can arise from having to do two layers.
Send us an email at order@dischargescreenprinting.com if you have any questions.