Computer monitors, scanners and digital cameras present all visible colors using the three primary colors: R- Red, G- Green and B – Blue, and this is known as “additive color mixing theory”.
In the printing processes, all visible colors are generated using C- Cyan, M- Magenta, Y- Yellow, and K – Black (noted as K- Key color). This is known as subtractive theory of mixing colors.
The range of colors that digital cameras can capture and computer monitors to show if by far larger that the gamut of colors even the most modern printing press can reproduce. Due to this, in many instances in the printing processes CMYK color gamut of the printing press is supplemented by additional colors or special printing effects.
Marking of number of colors printed on sheet
The colors in the processes of printing are marked in the 4/4 manner, meaning full color printing on both sides of the printing sheet (CMYK / CMYK). If one print job is marked 1/0, this means that only one color is printed on only one side of the printed sheet.
This terminology is also used in the varnishing process, so for example – 1/1 would mean a product was varnished on both sides.