Designer Tips: Colour
There are a large number of colour formats available, but they mainly breakdown into colour profiles used for print or for screen. These colour profiles include four colour process, Pantone, RGB and hexadecimal.
Color for print
Four colour process (CMYK)
Colour for print is determined by the printing process used. You are more than likely going to be printing using a four colour process – you may be familiar with the colour breakdown CMYK. This is the breakdown of colour into cyan, magenta, yellow and black (black is the K in CMYK, it stands for ‘key’ in printing lingo).
Colours are formatted this way when printing digitally or using a printing process called ‘litho’. Your office printer will likely use these four colours of ink. When specifying CMYK colours a value between zero and 100 is used to determine how much of that colour should be used. In this way a recipe is created for a specific colour. The Ralph brand green is C:45 M:0 Y:100 K:0. You can see from this that there is a lot of yellow and some cyan to create the green colour, but no black or magenta. If all the values were set to zero it would create no ink, white (as long as the paper was white).
The other most common colour format used in printing is Pantone. This is a catalogue of colours each with their own reference number. These are used by printers to mix up specific colours accurately by following a detailed recipe of inks indicated by the reference number. Colours created in this way are called ‘spot’ colours. They are typically used when printing with a small number of colour plates. For example, when printing two colour stationery, or when adding an additional colour which can’t be replicated in CMYK, such as a metallic or day-glo colour. These are less frequently used because of the increased production cost.
Colour for screen
The most common way of specifying a colour for digital is either by using RGB or a hexadecimal code. RGB is the screen version of CMYK, but instead of mixing inks, it mixes light. The three colours of light used are red, green and blue. In the same way as CMYK uses the four inks to create a huge amount of colours, the RGB colours can be mixed on screen to created a wide range of colours. When specifying RGB colours a value between zero and 255 is used to determine how much of that colour should be used in each of the three colours. The Ralph brand green is R:156 G:237 B:64. You can see that as expected it contains a lot of green in the mix. In contrast to CMYK when all the values are set to zero it would create no light, black. R:255 G:255 B:255 would create white.
Another method for specifying colour for web or digital is by using a hexadecimal code. You might recognise them as they are a series of six characters (numbers 0 to 9 and letters A to F) preceded by a #. For instance the hexadecimal code for the Ralph green is #9CED40. The six-digit notation is formed of pairs that refer to the three colours of RGB. In our green example, the 9C refers to red, ED for green and 40 for blue. Like RGB a colour specified with all zeros (#000000) would create black, whilst #FFFFFF would create white.