October '20

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8 4 G R A P H I C S P R O O C T O B E R 2 0 2 0 G R A P H I C S - P R O. C O M S I G N A G E & P R I N T I N G T H E D I G I T A L E Y E | S T E P H E N R O M A N I E L L O BLENDING MODES MAXIMIZE COLOR WITH OVERLAYS I 'm sure you're always looking for the ultimate in color relationships. You want images with impact that leap off the page. Achieving these effects requires knowledge of where to go in your software and what to do when you get there. Navigating complex graphics software programs can be challenging, and sometimes the usual color adjust- ments like levels, curves, brightness and contrast, and hue/saturation just cut the edge. COLOR SANDWICH Let's say that you place two color slides on a light table. You can see their con- tent as the defused light from the table passes through them. Place one of the slides on top of the other. The colors of both slides mix together and become darker and a bit more saturated. Now, suppose you have a box full of special gels. Each gel can be independent- ly sandwiched between the two slides to control the color relationship of the su- perimposed colors. In the parlance of digital art software, these virtual gels are called blend modes, and you'll find them in several of the features of image edit- ing and vector graphics software. Blend modes mix the colors of aligned pixels on consecutive layers. They can also be as- signed to the painting and editing tools, and to fills, strokes, and layer styles. LAYERS The ability to combine the color informa- tion on consecutive layers has the poten- tial to produce interesting results. As I've always said, in digital graphics software like Adobe (Photoshop and Illustrator) and Corel (PaintShop Pro) products, lay- ers is where it all happens. When specific content resides on a single layer, almost any kind of manipulation is possible. In addition, layer masks enable pre- cision targeting of image content, and layer opacity determines the strength of a particular edit, especially where color overlays are concerned. Extraordinary color control is possible when blend modes are used, and blending the colors of two or more layers is one of the keys to color magic. SIMPLE MATH A blend mode is a mathematical for- mula called an algorithm that relies on the existing color values of the layer content. With an RGB image, the red, green, and blue numerical values of each pixel on the consecutive layers are calcu- lated. The color values between the two layers are then modified based on the blend mode's algorithm. The color mode of an image also af- fects the results. The same blend mode applied to an RGB or CMYK layer may produce different results (Figure 1). Figure 1. The color mode of an image affects the results of a blend mode. The same blend mode, in this case Difference, applied to an RGB or CMYK layer may produce differ- ent results. (All images courtesy Stephen Romaniello)

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