What is Discharge Printing?

The simplest explanation? Discharge ink is a water based product that is formulated to deactivate the dyes used on natural fabrics.

What it Does.

You have probably seen many shirts with a very soft print that looks like the color of natural cotton – this is discharge printing. Discharge screen printing can be used to print colors on dark garments that in the past would have required an additional layer of white ink in order to achieve proper opacity of top colors.

Discharge Ink, Not Some Gross Stuff.

In its basic form, discharge is a clear ink with an activator added. The activator is Zinc Formaldehyde Sulfoxylate, and this is what causes the dyes in the fabric to be deactivated. Printing a straight discharge ink typically ‘bleaches’ the fabric down to its natural color, a slightly off white. Discharge inks work well on fabric that is dyed with reactive dyes, although some dyes are more resistant than others, often those colors are in the kelly green, purple and royal blue families. When discharged, these resistant fabric dyes yield a more muted print that is usually a lighter tint of the base fabric color.

Pigmented Discharge

When we need to print a color rather than clear dischrage ink we will add water based pigments to the ink in order to essential re-dye the fabric with the color of our choice. This allows us to maintain tight registration and bright prints on dark fabric without the use of an underbase. For the ultimate in soft colorful prints, pigmented discharge is the way to go. We use discharge inks so much that we just call all of our inks ‘water based.’ If the print goes on darks we add the discharge activator, otherwise it is the same ink chemistry.

100% cotton with a clear discharge print, bleaching the fabric to its un-dyed color

↑ 100% cotton with a clear discharge print, bleaching the fabric to its un-dyed color.

Bright AND soft prints on dark fabric.  No underbase!

↑ Bright AND soft prints on dark fabric. No underbase!

Some dyes resist the discharge reaction

↑ Some dyes resist the discharge reaction and take on a tint of the original fabric color. Still looks cool but don’t cry when you can’t get a bright white on kelly green. Come to peace with it.

Comments

  1. Hi, i was wondering how you get your waterbase whites so bright, i tried the premix discharge white and its not to great.

  2. @Brock – We’ve tinkered with and created our own recipe for discharge white that works well for our shop. We ended up mixing an existing brand of off-the-shelf discharge white with some white pigment and a brite discharge base. This ink formulation has worked really well for us. Otherwise, we also use highly tensioned screens and mesh with a high percentage of open area so that we can get excellent penetration and coverage with a single hit.

  3. When you discharge print a shirt is the color removed completely all the way through the fabric? If you turned a discharge printed shirt inside out could you see where it’s been discharged?

  4. Jason, we typically discharge the fabric down to a visual depth but not all of the way through the garment if we can avoid it. When driving the ink further down into the fabric you end up depositing more pigment in the fabric giving it a heavier feel.

  5. is the metal band t-shirt which comes is also a discharge print?

  6. Would you be able to print a water based image on black wool ex. A thin light weight wool sweater?

  7. saran Vanan says:

    Discharge print was before washing it\’s looking bright but after washing it\’s looking fade out , how to controlled the brightness , any formulas please give me I want to improve my business

  8. My discharge paint (White paint) has yellow appearance when the first printing. Second day when I print the same paint , it looks whiter than first day. I don’t understand why the colour change.

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