The colors you see on your screen never exactly match the colors in your prints. This is because the colors on screens are generated by combinations of three colors: red, green, and blue (RGB). Conversely, digital printers use anywhere from four to eight ink colors to reproduce the image from your screen. CMYK (cyan, magenta, yellow, and black) is the standard for four-color digital printing.
Computer monitors emit color as RGB light. Although all colors of the visible spectrum can be produced by merging red, green, and blue light, monitors can display only a limited gamut (range of color) of the visible spectrum.
Printed products absorb or reflect specific wavelengths of light, unlike a screen that emits light. Cyan, magenta, and yellow pigments or dyes serve as filters, subtracting varying degrees of red, green, and blue from white light to produce a selective gamut of spectral colors.
As you can see, there is a marked difference in how both types of color generation work. One is additive; the other is subtractive.
In digital product decoration, you design in an additive environment (RGB), and then the printer and software have to convert those colors to work in a subtractive environment (CMYK). Color management – or color correction – is the process of adjusting this color transformation so that you can produce the best quality results on your substrate.