OUAN502 - The Differences Between CMYK & RGB

During the responsive module this year I came across in one of the briefs I was doing a requirement that stated the files must be in CMYK format. I had accidentally started creating my image using RGB settings and was aware that by converting directly to CMYK there could be a loss or change of colour. During a conversation with Mike I had about it he outlined for my the differences between the colour modes and explained to me that CMYK contained less colours. After I spoke to him I thought it would be worthwhile to try to understand this further, and with it being a requirement of this brief I'm sure it would come up again at some point. So, by researching further I was attempting to understand better and hopefully be able to apply what I learnt to my work when approaching some of the technical requirements of briefs.

CMYK: Cyan - Magenta - Yellow - Black
RGB: Red - Green - Blue

I first found out that CMYK and RGB colours render differently depending on which medium they are used for, for example if the colour is being used on screen or web, or for print. This made sense straight away because I was aware that a lot of printing is produced using the CMYK colour format, as was the brief I was doing at the time and hence why they wanted specifically CMYK. CMYK is used for printing if the printer in question is using a digital printing method. The way this works is that because CMYK consists of four colours, (cyan, magenta, yellow and black) it mixes different amounts of each to create the desired colour when printing. The process of finding the correct amounts of colour to create the image is subtractive, which means that each additional unique colour means that more light is removed, or absorbed, to create colours. The colours are essentially being added from light to dark - with black being the most absorbent. Specifically about the use of black in CMYK printing, firstly the other three colours are added but in the dark areas of an image this will only create a dark brown. Finally, the 'K' colour, or black, is used to completely remove light from the printed picture. The removal of light in this way is why the eye perceives the colour to be black. In contrast to this there is RGB. RGB is the colour scheme most often associated with displays, for example, LCD monitors, digital cameras and scanners. Contrary to the way CMYK colour operates, RBG is an additive type of colour mode. By this it means that the primary colours, red, green and blue, in various degrees to create a variety of different colours. In terms of value and the calculation of colour, in the instance where all three of the colours (red, green, blue) are combined and then shown to their highest value, the result is a pure white. Whilst at their lowest value, the result is black. Different software such as photo editing software often uses RBG over CMYK because it contains more colours.

To summarise, when printing use CMYK and when creating something that will only be seen digitally, use RBG. Interestingly, I found that CMYK does not include a white colour. This is because the assumption when printing is that the image will be printed onto white paper. Furthermore, the reason RBG works well with onscreen visuals is that monitors are made up of small elements called 'pixels'. Pixels are allocated of three light units, one for each red, green and blue. The RGB values are applied to these pixels in turn making it so each pixel has a set luminosity for each of the colours within the pixel. Finally, there isn't a perfect correlation that can be achieved between the two colour modes, however if it is converted correctly an almost seamless match can be made - which is what I was able to do to save my work when I created it in the wrong colour mode at the start.