Popular in the 19th century, discharge printing fabrics involves removing dye from fabric to create a print.
Discharge printing is related to dyeing, but it is a slightly different process. It refers to a technique of creating prints on fabrics where a bleaching agent is applied, which removes some or all of the dye.
According to the Britannica Online Encyclopedia, “discharge printing, also called Extract Printing, is a method of applying a design to dyed fabric by printing a colour-destroying agent, such as chlorine or hydrosulfite, to bleach out a white or light pattern on the darker coloured ground. In colour-discharge printing, a dye impervious to the bleaching agent is combined with it, producing a coloured design instead of white on the dyed ground.”
Discharge printing is among a classification of textile printing techniques that dates back to the 12th century. The technique has gained strength in the last few decades and even more recently among those in the screen-printing industry.
Discharge printing is used on dark and medium-colored fabrics to create patterns that are white or colored. The fabric is dyed and then the color is discharged or bleached out to produce the print.
Thanks to new advancements in the chemicals and processes, discharge printing has opened up possibilities for screen printers because opaque, bright colors can now be placed over dark colors.
Not all fabrics are suitable for discharge printing. For a fabric to be compatible, it must be made of all natural fibers, such as 100% cotton. Also, the dye that is in the fabric must be dischargeable, which usually means it has been dyed with a reactive dye. The fabric should not have been re-dyed, as this may result in an unexpected discharge that showcases the original dye color, rather than the color desired.
Because different amounts of bleaching agents and dyes are required for discharge printing fabrics, the technique takes a certain amount of trial and error. The maker must add discharge solution to the water in order to extract the dye from the fabric. But it can be difficult to determine exactly how much solution is required. Once the color has been extracted, the result is a color similar to un-dyed cotton, a shade of off-white. In some cases, a different color is put in at the same time that the pigment is taken out.
A good place to start discharge printing fabrics is with the manufacturer’s directions. If that doesn’t produce the desired results, it may be necessary to play with the concentration of solutions. Depending on when you place the discharging solution, you will create different results. Also, consider using water at different temperatures as well.
Don’t despair if you don’t see results right away. Especially with darker fabrics, discharge printing can take some time to show up.