We absolutely love the results of printing with discharge ink. This waterbased method is for dark colored clothes and has been around for over thirty years. It has recently cycled back around due to the popularity of re-creating the look of vintage t-shirts. The colours typically don’t retain their vibrancy as regular plastisol printing but the feel is ultra soft and (when done properly) and can last longer than the shirt itself. Regular screen printing uses plastisol ink, which is a rubber-primarily based product. Plastisol ink lays a somewhat thick layer on top of a shirt’s fibers and normally requires multiple print layers… leaving a thick vinyl sticker-like feel on the garment. For example, if you’re wanting to print white ink on a black shirt, that white ink would need to be printed 2 times (print, flash, print) so the print appears bright and to prevent garment color migration. (A fancy way of saying you won’t see the color of the garment bleed through the imprint) Screen printing discharge ink printing is difficult and requires a ton of expertise. Make sure your printer knows what they are doing especially if you are supplying the garments. This technique should only be attempted by the most experienced screen printers.
How does discharge ink work?
Discharge printing bleaches out the original color of the garment and replaces it with the new color, or pigment. This method works only with one hundred percent cotton shirts that are dark colored. Polyester is a artificial material and will not react to discharge ink. There is a 12 hour shelf life to discharge ink, what ever isn’t used has to be thrown out. Hence the extra charge for using this process.
So, let’s say your wanting to print on a black t-shirt with white discharge ink. Seems easy right, not exactly… You initially would need to start out with a non-active base solution, then add white pigment, and then a little bit of activator (aka. agent or parolite) to bring the ink to life. The shirt itself additionally needs to be tested as all shirts can react slightly differently. The apparel trade is known for “over-dying”. Over-dying is when a t-shirt manufacturer runs out of black tees and needs to create stock fast. If they happen to have tons of red tees in stock, but no black, they may take that inventory of red and dye them once more in black to fill stock. That causes huge issues with discharge ink as a result of the white pigment desired, now turns pink upon testing. The good t-shirt brands constantly take a look at every new batch of tees to be sure their suppliers overseas aren’t over-dying. Most dark colours discharge well, except, kelly green and royal blue colored t-shirts.
The great news is, that once the job is setup and running, there’s no underbase needed or flashing ink process, so less product is employed and production time is quicker. Discharge ink is friendly to the environment.
In order for discharge and water- based ink to cure properly, we have to run the printed t’s through an oven for at least two minutes.
This process is technically difficult and tedius and comes with a minimum quantity threshold of at least 240 pieces to justify the added manual labor, ink waste cost and steps in the process.
In summary:
Discharge ink…
• Is for dark, cotton T’s only
• Bleaches out the dye of the tee and replaces it with the newly mixed color
• Is environmentally friendly
• Feels ultra soft
• Resembles vintage style
• Requires a very experienced printer
. Has minimum quantity restrictions
