Intrigued by water-based inks? Water-based inks are great because they feel so soft on the garment and simple to print basic jobs, but it becomes challenging when printing complex art and it requires more legwork. Whether you’re ready for a new challenge or you received a request from a customer, printing with water-based inks is a whole new ball game compared to printing plastisol inks. Ink master Colin Huggins has shared helpful knowledge you need to know about water-based printing to help you decide if it’s right for you.
Photo by Symmetree.
WHAT IS WATER-BASED INK
Water-based ink is the umbrella term to describe all inks that use water as one of the solvents in the ink system. The term covers two types of water-based inks — low solids and high solids.
Low solids is a traditional water-based ink. It’s meant to be printed on lighter garments because it has no opacity. Low solids water-based ink is the softest ink because it goes into the fibers of the shirt. Discharge ink is a cousin to traditional water-based inks. While discharge ink has the agent that strips the color from the shirt, both have an incredible soft-hand feel.
High solids water-based ink is what you mainly see on the market today. The ink has a thicker body and has better coverage and opacity. It’s soft, but not as soft as low solids water-based ink — you can feel the ink on the shirt printed with high solids water-based ink. They also print more like plastisol inks (underbase and separations are almost interchangeable between the two). While some high solids inks are high solids acrylic (HSA), others have urethane included instead of acrylic. Urethane creates more plastisol-like properties while still being categorized as water-based ink.
These newer ink systems actually use little water in them. The only time you would use water in the ink systems is to help disperse acrylic resin. If there is no acrylic resin and has all urethane, odds are there's little to no water. Almost all liquids are a solvent. New ink systems are moving away from water (still a little bit, but not as much) to solvent. It’s becoming more like solvent printing than water printing.
We dove a little deep there, but it’s good to know that this topic (like every topic in screen printing) is expansive and complex. The main takeaway is that water-based inks have water in them, two types exist, and you’d most likely get your hands on a high solids water-based ink.
Photo by Symmetree.
HOW IS WATER-BASED INK DIFFERENT FROM PLASTISOL INK
Plastisol is an oil-based PVC ink system. Plastisol does not have water in it. The water, or lack of water, makes a huge difference when it comes to on press usage, flashing, and curing.
Since plastisol does not have water in it, you do not have to worry about evaporation. You could start a print job, leave in the middle of production, and return the next day to continue printing the job with no issue. That’s not the case with water-based inks. As soon as you open the bucket, evaporation starts to occur. While you’re printing, you have to be conscious of how much the ink has been exposed to the air and know how to adjust the ink during production to maintain consistency. For example, the ink will look lighter at the beginning of the process and as you print, the water evaporates, creating a higher concentration of ink/pigment, and leaves the pigment behind, making the color look darker.
Flashing a print will procure different results for plastisol versus water-based ink. For plastisol, you’d flash the print to get a partial crosslink in the ink system — gelling the ink. The chemical change in the ink makes the print more like a solid sheet. With water-based inks, you’d flash the print to evaporate the liquids. The print will not gel like a plastisol print. The point of flashing it is to dry the water-based ink. Usually printers print-flash-print when printing an underbase. During this process, water-based inks inherently will look more transparent when printing on the base white compared to plastisol. High solids water-based inks have a slightly lower opacity compared to plastisol, which is why you’d need to work a little harder compared to printing plastisol.
Lastly, the biggest difference between the two is curing. Curing plastisol ink seems like a breeze compared to water-based ink. Plastisol ink just needs to reach cure temp through the whole ink layer. Curing water-based ink is much more involved. First, you need to evaporate all the water. If you don’t evaporate all the water, you cannot cure the ink. Once all the water has evaporated, the remaining ink layer (the resins in the ink) need to reach the recommended cure temperature and hold at that temp for a minimum of 20 seconds. For Colin, a water-based print takes one minute and forty-five seconds in a forced air conveyor dryer for it to be evaporated and cured properly. It’s definitely not the simplest process. Even if you have a gas dryer, it is still recommended to cure for 1:30 - 2:00 depending on your heat settings and dryer load capacity.
WHY WOULD YOU PRINT WATER-BASED INK
A number of reasons exist to print with water-based ink. Many people love the soft-hand feel of water-based prints. Printing with water-based inks can also create a great vintage, faded print.
If you’re looking to do more eco-friendly printing, water-based inks come out ahead of plastisol inks in this arena. Check out this article if you’d like to learn more about the eco-friendliness of water-based ink.
Another reason to use water-based inks is due to cleanup. You don’t need any harsh chemicals to remove the ink from the screen. Water works, or you can use eco-friendly products like Aqua Wash to remove any ink that’s stuck in the mesh. It’s pretty painless.
Others print with water-based inks because that’s what their customers want, which is what it comes down to in the end.
WHAT DO YOU NEED TO PRINT WATER-BASED INK
As we touched on earlier, you need the right equipment and supplies to achieve a good water-based print.
First up, the darkroom. When printing water-based inks, the emulsion needs to be water and solvent resistant. The quality of the exposure unit will always affect the resistant properties of emulsion. If you have a lower-powered light source but want to print with water-based inks, use a dual cure emulsion. It’ll work best with these types of exposure units, but the emulsion may not hold up for the entire print run. If you need to do a longer run, we recommend using an emulsion hardener or post-exposing screens before production.
Next, on press. Keep a spray bottle nearby to maintain consistency in the ink. Remember, the ink starts evaporating as soon as you open the container. Leaving the press alone for five minutes will have an impact on the ink quality. If you live in a humid climate, you’ll most likely print with little to no issues. If you have a drier environment, you will run into a lot of issues. A humidifier may be helpful.
Photo by Symmetree.
Lastly, but most importantly, curing. To cure water-based ink, you need to evaporate all the water, reach cure temp, and hold at the temp for at least 20 seconds. The most ideal situation is to have a minimum six-foot forced air conveyor dryer; you’ll be able to accomplish cure in the dryer in 1:30-2:00 minutes. Unfortunately, not everyone can get their hands on a big conveyor dryer, which is why it’s recommended that almost everyone uses Warp Drive.
If you have a heat press, that’s the next best option for curing water-based inks. With a heat press, you’d hover it over the garment to evaporate the water and then press it to cure it. It’s a consistent, reliable heat source. The downside to using a heat press for curing is the fact that it’s time consuming.
If you use a flash dryer or a small conveyor dryer, you’re going to need a low cure ink additive like Warp Drive. Flashes and small conveyors do not provide a consistent heat source, so it’s incredibly difficult to achieve cure with them alone. Warp Drive is the cheapest insurance possible, and it pays off. You add it to the ink before you start printing. Use your flash or conveyor to evaporate the water. Set the garment aside for 48 hours and the additive will chemically cure the print. Low cure ink additives are great. They’ll cover up mistakes you didn’t even know you made. If you decide you want to print with water-based inks but don’t have the best curing devices, get something like Warp Drive. It’ll reduce the likelihood of angry customers returning because of prints washing off.
If you have decided that you want to try water-based printing, take a look at this free, online course. The class will walk you through art preparation, screen making, inks, press setup, shirt selection, printing techniques, and cleanup. If you decide water-based printing is right for you, we want to see your prints! Tag us or use #ryonet and we’ll share it with our audience.