Discharge Ink Screen Printing

What is the difference between discharge ink screen printing and regular screen printing?

We love the results of printing with discharge ink.  This waterbased process is for dark colored garments and has been around for over 30 years. It has recently cycled back around do to re-creating the look of vintage t-shirts.  The colors usually don’t retain its vibrancy as regular plastisol printing but the feel is ultra soft and (when done correctly) will last longer than the shirt itself.  Regular screen printing uses plastisol ink, which is a rubber-based product. Plastisol ink lays a somewhat heavy layer on top of a shirt and normally requires multiple print layers… leaving a thick vinyl sticker-like feel on the shirt.  For example, if you are looking to print white ink on a black shirt, that white ink would need to be printed 2 times (print, flash, print) in order for it to look bright and smooth. Plastisol ink is great for printing inside neck size labels because the ink does not bleed through to the other side of the garment.  Screen printing discharge ink is complicated and requires a lot of experience. Make sure you choose the right screen printer!

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 process only works with 100% cotton shirts that are dark. Polyester is a synthetic material and does not react to discharge. There is a 12 hour shelf life to discharge ink, what ever is not used gets trashed!

So, let’s say your looking to print on a black t-shirt with white discharge ink.  Seems easy right, not really… You first need to start with a non-active base solution, then add white pigment, and  then a small percentage of activator (aka. agent or parolite) to bring the ink to life.  The shirt itself also needs to be tested as all shirts can react slightly differently. This industry is known for “over-dying”. Over-dying is when a t-shirt manufacturer runs out of black tees and needs to replace them fast. If they have a ton of red tees in stock, they may take that inventory and dye them again in black to fill stock. That causes huge problems with discharge ink because the white pigment desired turns pink upon testing. The good t-shirt brands constantly test each new batch of tees to make sure their people overseas aren’t over-dying. Most dark colors discharge well, except, kelly green and royal blue colored t-shirts.

The great thing is, once the job is setup and running, there is no base needed or flashing of ink, or trapping so less product is used and production time is faster. Discharge ink is eco-friendly!

In order for discharge and water-based ink to cure properly, we have a huge 28 foot gas dryer that pumps tons of heat.  At least 2 minutes of heat time needed.

Because this process can be so tedious (especially with multiple ink colors) InkMyTee.com has a 150 piece order minimum.

Summary:

Discharge ink…

• is for dark, 100% cotton tees 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 experience

• expires after 12 hours

Plastisol ink…

• is rubber based and easy to work with

• usually needs 2 layers of ink on dark tees

• the colors stay vibrant

• has a long shelf life