CMYK stands for cyan, magenta, yellow and black and is a commonly used colour model of four inks within colour printing.
CMYK is the colour model used for printing and is displayed on products like brochures and business cards through lithographic printing. Whereas RGB (Red, Green & Blue) is the colour model used for devices such as a computer monitors or screens as they can only be viewed with natural or produced light, and cannot be used in lithographic printing as it would have to be converted, however, some of the RGB colours especially the bright colours are lost during this conversion. While as CMYK conversions dull some of the colours. This is why most designers choose to create their own designs in CMYK to avoid any panic conversions and disappoint the customers.
The RGB colour model is based on projecting light to create colour, this is referred to as additive colour. When all three colours are combined (Red, green & blue), it creates white. This is the case for devices such as your computer and TV screens. This means that for the RGB colour model, black is the absence of all colour. When CMY (Cyan, magenta & yellow) are mixed they create black. This is the case for most printed media such as business cards, brochures, posters, etc, as CMYK displays better on paper. The pigments of CMYK are printed in small dots and if you were to take a magnifying glass to the paper, you’d see that it would mainly be just a bunch of small dots spread out across the print. Opposed to the RGB colour model, for the CMYK colour model white is the absence of all colour. Adobe Photoshop, Illustrator and InDesign all provide presets recommended for CMYK press setups which is very useful. You can also find out how to convert RGB to CMYK very easily with a quick internet search. In conclusion, whenever you are designing for print, make sure that it’s in the CMYK colour model. Otherwise the final printed product will not look as it did when it was being displayed in RGB on your computer screen.
This may sound like a very simple thing to solve with a quick Google search, but the actual answer has an element of the unknown to it. There are two common answers for why K stands for Black and here they are:
1. Wikipedia’s description of why K is Black is “The “K” in CMYK stands for key because in four-color printing, cyan, magenta, and yellow printing plates are carefully keyed, or aligned, with the key of the black key plate.” this is because the black plate in four-colour printing pushes the contrast and creates detail.
2. The second answer that some will give you is that it was to prevent blue being easily confused with the B for black term. This answer is considered a myth, but there is some logical reasoning behind why printers would change B to K because of the confusion between blue and black. The reasoning behind this is if the press was loaded with blue ink at the end of the day, the entire job would have to be started over. Which, as you can imagine would cause quite the frustration amongst the printers. So it could be that key was a random word picked out of no where to stop the confusion between blue and black. Maybe the real answer will never be known, but it certainly is a mystery for the printing industry.