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 fine points of artwork revision for digital printing are not that dissimilar to prepping for offset or screen printing. The only real difference is that the file needs to be of a higher resolution than for screen printing, and you may have to adjust the gamut and hue range (as discussed earlier in the gamut section). Many printers strive to have graphics that are at least twice the resolution necessary for the output device. So if your printer can reproduce 150 dpi on the shirt, then you should start with a 300-dpi file. Fortunately, the weave of garment fabric is such that the results from an inkjet print are usually a little more forgiving. You can have a 250-dpi file for DTG output (that is at actual size, of course). Make sure that your file isn’t too big, either, as some of the printers can get stuck or not print properly if the file resolution is too high. Check your specs and make sure to review the quality of the file for the following:
Edge quality The sharpest areas of contrast in an image, such as an outline on a cartoon, should have a clean edge if possible. Try to avoid or correct ghosting and compression glows or distortions. Low-quality images that are enlarged may need to be redrawn on the edges or at least sharpened in places. Sometimes a Sharpen filter that is used on the black channel in CMYK or the lightness channel in L*a*b* color mode can give good results without all of the extra work.
Color blends If the image has smooth transitions of color, then it’s important to pay specific attention to these areas because viewers’ eyes will be drawn to any imperfections in gradient blends. Careful selection and replacement, or blurring using a Gaussian blur to just the affected area, can fix such issues.
Contrast If the image looks dirty and washed out on the computer, it is unlikely to be vibrant on the printed shirt. One thing to try is to boost the contrast by 10-15 points, just to see what happens. Be careful that this procedure does not knock a bunch of colors out of gamut. Changing contrast can really brighten up a dull image—if you don’t overdo it.
Creating the underbase white
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