Discharge screen printing is one water based solution for light prints on dark clothing or textiles. It ticks the environmental printing boxes, but it is not without it’s limitations. Firstly we would not use this method for printing orders of less than 50 T shirts, the reason being the ink has a shelf life of less than 24 hours when mixed, this means there is waste on small orders or in a situation where ink use cannot be predicted accurately. Ideally we like to see print runs of 100+ for this process. Another draw back is in its ability to reproduce accurate colour across a range of different materials, discharge ink is a bleaching agent which when combined with pigments will colour the shirt, unfortunately the underlying colour of the garment to be printed is rarely white and will affect the final print, the underlying cotton colours that are most often found are pale blue, pale cream, pale pink, all will have a grey tone to them. Quite often black T shirts can be stock that has been re-dyed, so a T shirt may have been coloured red originally and later changed to black, a batch such as this can be problematic when using the discharge system.

It is not possible to use discharge printing on synthetic materials, an 80% cotton content would be the minimum requirement in our opinion. True whites are hard to achieve, and good bright reds are also very difficult to make permenant and these are things to consider when designing for this process. Greens yellows and blues are bright and permanent. Although an organic solution for screen printers discharge printing will need a wash before wear label.
Despite all the draw backs of this technique there are some circumstances where it excells, the final print has no discernable texture to it after the first wash and can be ironed over.

Related posts:

1. Formaldehyde Free discharge printing on T-shirts
2. Red discharge print, earth positive T shirts
3. Discharge T shirt print using index separations
4. Water based inks, another look
5. Index Separation Method for Screen Printing