By Jeff Leagon
Digital printers whose specialty is putting images on fabric typically utilize a dye-sub transfer or a direct-to-textile dye-sub print system because these systems are fabric specific. Those “specialists” know which fabric manufacturers and suppliers to go to for materials that are compatible with their systems. For them, the sourcing process is about selecting the best fabric for the particular job based on factors like texture, opacity and stretch.
Generally speaking, for dye-sub transfer printing, a fabric must be 100-precent polyester and prepared for printing by scouring and heat setting. Without these preparation processes, the fabric can discolor and shrink during the heat transfer process. Further, if a transfer dye-sub fabric has been treated to be flame retardant, it’s critical that the FR treatment does not discolor or become stiff during heat transfer. Either will diminish the aesthetic properties of the fabric and the finished piece.
For direct-to-textile dye-sub printing, the same requirements apply. Additionally, a special pre-treatment is needed to keep the ink from wicking into the fiber before it can be heat set. Fortunately, it isn’t necessary to have a “fabric specific” print system in order to print on textiles. UV-curable and solvent digital systems are being used for printing on a wide range of fabric and fabric-based media.
One of the most attractive features of a UV-curable print system is that it can print on virtually any substrate, including fabrics with no special pre-treatments. Since the inks are cured almost instantly, they don’t have a chance to wick into the fiber and distort the image.
One concern with UV printing onto fabric is that the cured inks tend to crack if the fabric is stretched or folded, so more dimensionally stable fabrics should be used. Flat bed or drum UV systems, which utilize vacuums to hold the media in place, are particularly well suited for use with canvas and other heavily coated fabrics.
Solvent print systems aren’t quite as forgiving as UV systems when it comes to printing on fabric. A pre-treatment or coating of some type is always necessary. Canvas and textile-based banner stock are the most common examples of fabric media being used with solvent systems, and there are many styles available.
The best way to find media that are compatible with your print system and appropriate for a specific application is to talk to the media manufacturer. Even if you purchase through a distributor, speaking to the manufacturer will insure that you know about all media options and that you aren’t wasting time and money on the wrong materials.