DISCHARGE INKS


Posted in Screen printing

a preview of a t-shirt printed with discharge inks

Screen printing with discharge inks offers a unique solution for garment decoration. Discharge inks will let you achieve soft hand prints using bright colors on dark fabrics. Because of this uniquely formulated water based product we can easily give your graphics a softer and more vibrant appearance. Screen printing with discharge inks produces lighter, more breathable prints that become one with the shirt’s fibers.

Water based inks soak into the fabric instead of sitting on top. Therefore the print still shows the weave of the shirt making it much lighter and breathable. When the garment is dark and the print is bright we need to mix the ink with an agent that deactivates the original dye used on fabrics. In other words it bleaches out the dye leaving its natural tan cotton color showing through. Once the dye has been removed, the pigmented discharge ink will then re-dye the image area with your desired ink color.

ADVANTAGES OF DISCHARGE INKS:

  • Exceptionally soft hand and light weight.
  • Intense pigment colors.
  • Ease of use and breath ability of the ink on fabric.
  • Works on most 100% cotton garments.
  • No under-base required.

DISADVANTAGES OF DISCHARGE INKS:

  • Do not work optimally on poly blend fabrics.
  • Some dyes don’t react properly with discharge inks.
  • Can’t guarantee 100% pantone color match in all garments.
  • Whites might look a little tan on some garments.
  • Ink curing requires high temperatures and long exposure to heat.
  • Colors might fade after many washes (up to 25%).
  • Certain shirt styles discharge better than others. Proper testing is key.
  • Must wash the garment in order to achieve the “no feel” of ink state.
  • Discharge inks might leave a smell that goes away after washing.

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THE PROCESS:

Discharge is basically a clear ink with an activator added called Zinc Formaldehyde Sulfoxylate. This bleaching agent deactivates the dyes in the fabric. Instead of transferring standard plastisol ink on top of the fabric, printing a straight discharge ink ‘bleaches’ the fabric down to its natural color, a slightly off white.

If we want to print a color rather than clear discharge ink we need to add pigments to the ink in order to re-dye the fabric with the color of our choice. Pigmenting discharge can be difficult to achieve exact color results, as the discharge permeability of the garment affects the color. What you see is not what you get when mixing the pigments or even printing them. In order to see the final results the ink must be properly cured at long exposure to high temperatures.

THE RESULTS:

Discharge inks work best on natural 100% cotton fabrics with reactive dyes. When the garment is fully reactive you get vibrant colors in an ultra soft print that will last forever with proper care. When the ink is cured and ready you can still feel a little bit of texture on the printed area but it will disappear completely after the first wash.

a side by side comparison of different discharge inks, dyes and materials

Some blends are more “discharge friendly” than others and some dyes are more resistant than others. Often those resistant dyes 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 tone of the base fabric color. The same happens with some polyblends and triblends where you can still see the print but the final look is a bit faded or transparent. Sometimes this can be a desired “vintage” appearance when you want your decoration to look washed and used.

Depending on market demand some garment manufacturers might end up re-dying (often in black) overstock of garments in unpopular colors. The formula used to re-dye the fabrics is usually more powerful than the standard. Therefore these garments will give mixed results when discharging because there are now several layers of dye.

At Psylo Graphics we will only provide you with the right garment for the desired results but if you want to provide us with your own garments to screen print with discharge please make sure that they are discharge reactive. Re-dyed shirts are usually easy to identify because they tend to be softer as if they have been washed, they are almost always black, and a big indicator is a stained woven label in the neck because they are dyed after they are sewn.

a comparison between discharge inks friendly dyes and resistant dyes

CONCLUSION:

Screen printing offers a wide range of alternatives in techniques and materials that will affect the final result of your product. As we learned, discharge inks are a great solution for big prints that need to stay airy and lightweight. We can use them as an under base for water base or plastisol inks and they can maintain the integrity of all the important details of your screen printed images.

It is true that discharge inks limit your garment color and blend of choice. At the same time though, we can use the partial effectiveness of discharge on not reactive blanks to our advantage. What is important is to be able to know and predict results or test garments before production.

Some clients want to avoid heavier plastisol prints on dark garments that need an extra layer of white ink and eventually crack and peel over time. Direct or dye discharge is the preferred method for most decorators and consumers and here at Psylo Graphics we’ve been mastering it for more that 15 years. Contact us today to place an order or to learn more about discharge printing!

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