What Is Discharge Screen Printing?

By ShirtSpace | Aug 29, 2024 |  Updated Aug 29, 2024

Tired of thick, plastic-y feeling screen prints? Discharge printing has come to the rescue! If you are looking for incredibly soft prints that are made to last, then discharge printing could be a perfect choice for your custom designs. Plus, if you like working with darker-colored t-shirts, it might be worthwhile to consider switching to discharge t-shirt printing over traditional screen printing methods.

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What Is Discharge Screen Printing and When You Should Use It

So what is discharge printing, and how does it differ from other forms of screen printing? Many screen printers use what is called plastisol inks. These inks tend to be thicker and sit on top of the fabric. You can feel the print slightly raised above the material. Depending on the ink and technique used, plastisol ink screen prints might feel thick, and after many wears and washes, they might start to show wear – whether that be cracking or peeling. 

For those who prefer a screen print that feels flush with the fabric, discharge inks are a fantastic solution. These special kinda of water-based inks include an activating agent (often zinc formaldehyde sulfoxylate) that either removes the dyes in the fabric when applied to targeted areas, lightens them to their original shade, or often replaces the dye with a new color. The final product is a vivid and ultra-soft print that other printing methods cannot always provide.

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Understanding Discharge Printing

If you are familiar with sublimation printing, then it might be helpful to compare it to discharge printing to understand what exactly it is. Discharge printing’s results look similar to sublimation printing, with smooth prints that would be undetectable if you were to run your fingers over the design blindfolded. The difference is that although sublimation printing also produces smooth prints, this method dyes the fibers. With discharge printing, the dye is removed or removed and replaced. Another difference is the fabric limitations with sublimation, which usually requires 60% polyester or more to yield vibrant prints and also light-colored fabric. The less polyester, the more faded and vintage the prints will look. Dark fabrics will make the design less visible and warp colors. Sublimation is also typically achieved using a heat press, which discharge printing is screen printed and then the design is cured using heat.

Discharge printing is nearly opposite to sublimation in its fabric requirements, which instead requires natural materials to achieve and is often done on darker fabrics. Super light-colored fabrics have no need for dye discharge to lighten up. Natural materials that are suitable for discharge printing include cotton or hemp. Synthetics like polyester material won’t react the proper way to discharge print. However, you can still discharge print on blends, such as cotton/polyester blends. The more synthetic fibers in the material makeup, the more worn-in or vintage the print will appear. Once you have too much polyester, the print will be illegible. 

The Process of Discharge Printing on Fabric

We know you are excited to start your discharge screen printing journey, but when learning how to do discharge printing, remember to prep the fabric first. You must check that the fabric was originally dyed with dischargeable dye, typically called reactive or direct dye. If you are dyeing the garment yourself and then discharge printing, dye the fabric with dischargeable dye, which is typically a reactive or direct dye. Then, you can start discharge ink printing. The water-based discharge ink is applied to the fabric via screen printing. The final step is exposing the print to heat, which cures the ink and activates the discharge agent. This is where the magic happens. The original dye is removed from the fabric, and the new color appears. 

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Benefits of Discharge Printing

Softness: By avoiding a layer of ink or a transfer sitting on top of the fabric, which is the case for many popular printing methods, such as direct-to-garment printing (DTG), direct-to-film printing (DTF), heat transfer vinyl (HTV) or screen printing with plastisol – discharge screen printing is very smooth and soft as the fabric itself.

Controlled Vibrancy: Discharge printing allows printers to achieve bold and bright prints and high contrast on dark garments. Screen printing on dark fabrics with plastisol ink often requires a white under base, which can make the print heavier and stiffer if trying to achieve vibrancy. Additionally, if you prefer a more vintage or distressed look – this can easily be achieved when discharge printing on fabric. 

Environmentally Friendly: Water-based inks are more sustainable because they are less damaging to natural ecosystems compared to other inks, since they do not require the same harsh chemicals. 

Discharge screen printing on a black t-shirt, using Ryonet’s Riley Hopkins screen printing equipment.
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Techniques for Discharge Screen Printing

Create Custom Colors: Mixing discharge ink with pigments to color match and get the exact colors you have in mind.

Overprinting: Discharge ink is first used to remove the original dye from the garment, then a second color is printed on top of the lightened area. 

Mixed Media Designs: Use discharge ink printing in combination with plastisol or standard water-based ink screen printing to achieve unique and design printing solutions. 

Discharge T-Shirt Printing: Best Practices

The best way to set yourself up for success with discharge t-shirt printing is to select high-quality natural fabrics, such as 100% cotton garments, especially if you are new to discharge screen printing or desire very clean-looking prints. Blended fabrics or those with non-dischargeable dyes can sometimes result in uneven or incomplete prints.

Due to this unpredictability, it is a good idea to test a small area of fabric on one sample piece before carrying out a full print. That way, you can identify any issues with how the fabric and ink interact before carrying out a full print run.

Another important aspect is to be careful with the curing process. Too little heat can interfere and result in incomplete discharge or dull colors, while too much heat can damage the fabric. Ensure the correct temperature with a temperature-controlled flash or conveyer dryer and regular temperature checks to ensure consistency. 

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Embracing Discharge Printing for Unique Fabric Designs

By learning the ins and outs of discharge printing on fabric, you can open up a lot of new possibilities when it comes to your custom apparel designs. Whether you would like to create bold and vibrant prints or something more worn-in and faded-looking, discharge printing is versatile and a nifty skill to have in your t-shirt printing toolbox. By taking the time to understand the science behind the craft and best practices to achieve desirable outcomes, you can easily up your custom apparel game with discharge ink printing.

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