Discharge Printing is a screen printing process where the same techniques and equipment are used as used for regular screen printing but instead of normal ink, discharge inks are used, which remove the fabric’s dye instead of putting a color on top of the fabric.
It is somewhat similar to bleaching in a design, except it doesn’t damage the fibers like bleaching would. It results in an extremely soft print. It is a process in which a discharge ink is used to deactivate/replace a dyed fabric. It is also called Extract Printing as the dye of the fabric is removed, and a lighter colour is achieved.
For example, we could dye a fabric black, and use a discharge print in white to print a white motif on the black fabric (a reactive or pigment printing technique would not show a lighter colour on top of a dark one). The discharge chemical comes in a few colours, so you could print red on black (the red “discharges” the black and replaces it with red). Other colours include pink, blue, yellow, grey, and olive green.
The discharge ink used is a clear liquid deactivator that contains zinc formaldehyde sulfoxylate which is what bleaches or reduces the shade of the original dye.