Striking a balance between vibrant colors and subtle details requires a careful approach to creating separations. Trimingham describes his favorite method in this month's column.
The curve-based separation in Photoshop is my favorite for capturing this style of separation and reproducing the best results on dark shirts. The colors in this style of separation are isolated using a variety of methods (Image>Mode>Color Range/Index Split/Calculations/etc.) and then editing them by using the Curves Palette dialog so that the density of the color will perform in concert with the testing performed. The ideal situation is for the final file to have the same values in underbase and overprint color as in the test file while using all of the same variables. If this is the case, chances are good that you won’t need to make adjustments on press.
The example shown in Figure 4 shows how this works in an image-separation set. The color that’s separated is captured first using an Image>Mode separation. This means that a duplicate of the image is split into CMYK using maximum black GCR in a custom setting to force all of the other colors into the CMY channels. These channels can then be used in whole or in part as separations when combined into the original design’s alpha channels that were built.
The next step is to apply the Curves menu to the selected area to boost the blacks and create a clear value range that will echo the necessary colors as in the fall-off test. Pay special attention to the image areas that’ll have very little or no underbase yet still need to show up slightly on the shirt (Figure 5). These areas can literally make or break the over-all design and either create the wow fac-tor or make people walk on by.
The role of the underbase
A big challenge to dark shirt printing is in getting the top colors bright enough while still maintaining some subtle effects in the shadows (Figure 6). The brighter the top colors are, the more opaque they tend to be and the less they will change as they fall off of the underbase. In an effort to create the best of both worlds, you can make some choices that improve the brightness of the most intense areas while maintaining the integrity of the murky shadows without flattening everything and losing the appeal. To define the choices, ask these questions:
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