Reaping the benefits of digital imaging on apparel requires command of art preparation. This article describes how to set up garment graphics for inkjet printing and examines the variables associated with this method of decoration.
The simplest long-term solution is to build a couple of action scripts in Photoshop to create an underbase and adjust it to compensate for the brightest and most saturated colors. A side note to think about when considering the construction of an underbase is whether or not to let the shirt come through the print. The old screen-printing adage says to use the shirt color whenever possible; however, this ability is a mixed blessing on the digital machines because some color separation would be required, thereby negating some of the benefits of inkjet printing. Some designs will look good either way, while others will look really bad without being knocked out (Figure 4).
Thankfully, the list of variables you must control in order for the digital printer to function consistently isn’t too long. A lot of it is common sense. Printers who have worked with sensitive equipment will find that they have an edge in some areas, as will screen printers who have already mastered water-based printing. Here are additional items to consider:
Garment-fabric surface The best surface for DTG printing is one that is as flat as possible, so you may benefit from heat-pressing garments before printing them (whenever it is safe to do this). Smoothing garments before printing can help ensure that no bumps brush the printhead.
Fabric weave and content The quality of a garment’s weave and the material from which it is made dictate ink formulation. For example, some printers won’t work on 50/50 cotton/poly. Test each major shirt brand to see which weave and fabric content give you the best print.
Absorption Inks soak into the shirt, so many of the DTG machines require the use of a pretreatment spray to slow the absorption and keep the colors on the surface. Test the volume and method of spray to achieve the optimal brightness on your machine and best fabric source.
Humidity The use of water-based inks requires that surrounding air have higher humidity to keep the inks from drying inside the printheads. Check the specs on the machine and modify the surrounding air as needed.
Temperature Think about water-based paint in a can and how it responds to temperature. If it gets too hot, you will have a brick in a can (or crusty ink in a printhead). If it’s too cold, it will flow like sludge.
Ink flow A DTG machine is simply a larger version of the tabletop printer that you might use to print on paper. If the ink stays too long without moving, it will gel up or lock into the printheads. These printers need to run consistently to keep the ink moving.
Air flow This is the enemy of water-based formulations in printheads. Keep fans and unnecessary air movement away from the printheads. Al- ways keep the cover on the machine when it’s not in use.
Curing This simplest and safest way to test the proper cure is to wash the garment right after curing. Water-based ink needs hot air flow to cure, so curing can take longer than what you’re used to seeing with solvent-based ink. If you’re working during a really humid day, count on having to extend the drying time to bake out any extra water.
Discovering and managing all of the variables in digital DTG printing enables you to control the process and use it to produce quality results. DTG printing can be rewarding when you learn to create your graphics that print as anticipated without requiring separating, lengthy press set up, and on-press color matching. In this process, your priority must be to keep everything consistent and efficient. If you’re an artist, this means you can focus more of your attention on producing high-quality images on T-shirts!
Thomas Trimingham has more than 16 years of experience in screen printing as an award-winning artist, separator, industry consultant, speaker, and author of more than 40 articles in industry magazines. He can be reached through his Website, www.art4screen.com.
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