Screen printing involves many different components to ensure you get the right results. If you’re new to this technique, you might come across items or terms that you don’t understand. One thing that often troubles beginners is discharge ink.
You’re aware that this is a type of ink, but what is it used for and what is its purpose? The team at Holden’s has put together this guide to help answer those questions and more.
What is Discharge Ink?
Discharge ink is a specific ink type that’s water-based and low in solids. This is used in discharge ink screen printing and is an important part of silk screen printing. However, while there are lots of water-based inks on the market, discharge ink is significantly different. Mainly, this is because it contains other components and ingredients - including something called a discharge activator.
This activator - or agent - is used to remove the dye from particular garments when printing. In turn, it allows you to add a new color without seeing any problems. Without discharge ink, you might not get the desired color when doing silk screen printing on darker garments.
What is Discharge Ink Used For?
As just mentioned, the key purpose of this product is for printing on dark clothing items or fabrics. The discharge agent strips away the current color on the item, leaving the natural fibers below. After this, the item of clothing no longer has its original dye, so the discharge ink can replace it with the color you’re using.
It’s important to keep in mind that while discharge ink is an important part of your silkscreen supplies, it isn’t used in all types of screen printing. It is a rather clever way of ensuring that you get the best possible results when printing on certain dark garments but isn’t used on light garments or with other types of materials. The chemical reaction that takes place will do so in just a few moments while printing, and you can see the results after.
A good way to demonstrate the benefits of discharge ink is by printing with and without it. Use the same print on the same item of clothing with and without discharge ink, and watch as the one with discharge ink produces better colors that aren’t faded or distorted.
What Should You Use Discharge Ink On?
This is a product that should only be used when fabric printing. As you may be aware, screen printing is beneficial because it allows you to print designs on multiple different surfaces - including glass and wood. However, you should only use discharge ink screen printing on fabric surfaces.
Specifically, the garment should be 100% cotton. Natural plant fibers in cotton react most effectively with discharge ink. You can technically use fabric that isn’t 100% cotton but be aware that you may not see the best results. It’s highly recommended that you steer clear of black polyester fabrics because the discharge agent simply will not work. Because of the make-up of the black polyester, the paint is unable to strip the original dye from it.
What Colors Are Good For Discharge Ink?
The fabric material is very important when using this type of ink, but so is the color of the material used. We have mentioned a few times that dark colors tend to be the best. However, some colors react better than others to the discharge agent. Usually, you should stick to colors on the reactive dye color chart. Reactive dyes work extremely well here and are much easier to strip from a garment. Therefore, your discharge ink can work perfectly and replace the old dye with a new one.
Our team strongly recommends you test the material and ink before printing. You should have some swatch cards handy with little tester pieces of fabric. Here, you can add some of your discharge ink to the swatches and use them to test the results. It should be very easy to see which colors work better than others, allowing you to start printing with more confidence.
How Are The Dyes Removed?
You know what discharge ink is, you know why it is used, and you even know what it is used on. But, one question you might still ponder is how the substance actually works. You’re now aware that this ink contains chemicals that basically discharge the garment and replace old dye with a new one. Below, you can see an overview of how this whole process happens:
- Discharge ink contains chemicals that work to destroy the dye molecules on an existing fabric
- For this to happen, a heat source is needed to heat the ink up to a high enough temperature - usually 230 degrees
- As the ink reaches this point, the component that strips the dye will activate and begin removing the old color from the fabric fibers
- The ink continues to heat up until around 260 degrees at which point the activator has now done its job, and the old dye is gone
- The color pigments in your discharge ink will now replace the old pigments on those fibers, creating a different color
After this, the garment needs to be cured, and then the print is complete. The good news is that you don’t need to worry too much about the chemical reaction as it all happens naturally. It’s very important to remember that you should have a good ventilation system in place as some chemical fumes can be released during discharge ink printing.
What To Look For When Buying Discharge Ink
Primarily, you want to look for a quality product. Thankfully, you’re in the right place as Holden’s Screen is known for our extremely high-quality silkscreen supplies. Beyond this, another key thing to be wary of is the shelf-life of the product. If the product has a shelf-life of 8 hours when activated, this means it will stop being effective after those 8 hours. So, if this amount of time has passed and you try to print with the discharge ink again, it probably won’t work.
Overall, discharge ink is a really handy tool if you are printing on dark fabric. The chemical reaction that takes place does a fantastic job of removing old dye and replacing it with a brand new color. Find the perfect discharge ink and other printing supplies today!