Color theory defining the CMY primaries as substances that "absorbed" only one of the retinal primary colors: cyan absorbs only red (−R+G+B), magenta only green (+R−G+B), and yellow only blue violet (+R+G−B). It is important to add that the CMYK, or process, color printing is meant as an economical way of producing a wide range of colors for printing, but is deficient in reproducing certain colors, notably orange and slightly deficient in reproducing purples. A wider range of color can be obtained with the addition of other colors to the printing process, such as in Pantone's Hexachrome printing ink system (six colors),
Combination printing Combination printing Combination printing is the photographic technique of using the negatives of two or more images in conjunction with one another to create a single image. Similar to dual-negative landscape photography, combination printing was technically much more complex. The concept of combination printing stemmed from the desire to create more of a fine art within photography and often more idealized images. Combination printing was popular in the mid-19th century due to the limitations of the negative's light sensitivity and camera technology. For example, the long exposures required at the time to create an image would properly expose the main