Growing up, I was always fascinated by colour. I remember watching my mum paint realistic landscapes mixing purple for clouds and orange for grass and wondering how this made sense. Throughout my design studies, I learnt about colour theory; primary vs secondary colours, that opposite colours on the colour wheel are complimentary, and the symbolic properties of a colour. But it wasn’t until I picked up a brush and started mixing paints that colour really sunk in.

For two years, prior to joining Hyphen as a book designer, I worked as a mural artist, painting graphics onto all kinds of walls of all kinds of colours.

I remember for one garden mural, I rocked up on site with my pre-mixed paints to find the wall that had appeared blue in the digital photo was actually an earthy grey in person. The cool undertones of the paints clashed with the warm grey background and the colours appeared almost fluorescent. This was a great lesson in colour theory.

When we talk about colour, we often refer to a colour’s CMYK or RGB make-up.

Referring to a colour by a hex code or a bunch of percentages may seem confusing, but it is a designer’s hack to deciphering colour.

What the colour codes mean

CMYK

Cyan (C), magenta (M), yellow (Y) and black (or key, K) make up the four primary colours used in full-colour printing. CMYK colours are built with varying percentages of each of these four colours. Think about the cartridges in your printer at home. They are most likely cyan, magenta, yellow and black.

designers use both CMYK and RGB colours

CMYK is subtractive, meaning it starts with white and as colours are added, light is subtracted and the canvas gets darker.

When it comes to the printing process, we can imagine it in the same way as paint. During printing, tiny ink drops are applied to the page in a pattern that corresponds with the CMYK make-up. For example, a colour that is 75% cyan and 25% yellow will print as a pattern of 3:1 cyan to yellow dots. Similarly, the same colour in paint will have a ratio of 3:1 cyan to yellow paint particles, only they are pre-mixed in a bucket.

RGB

RGB (red, green and blue) is the colour space of computer screens. A computer monitor consists of millions of dots in just these three colours. Whilst RGB can produce similar colours to CMYK, they will always vary slightly. You may have wondered why your photos look one way on screen and vastly different once printed.

designers use both RGB and CMYK colours

RGB uses additive colour mixing and works very differently to CMYK.  The colours are applied with light so the higher the percentage of each colour channel, the more intensely bright the colour becomes. If all RGB colours are at zero, it makes black (total absence of light), whereas if all colours are at their full intensity, which happens to be 255, then the human eye sees white (total brightness). This is why, when we mix red and green at high intensities, we see a light, bright yellow. If we were to do this with paint or in a CMYK colour space, it would appear brown.

It’s a tricky concept, but it highlights how different CMYK and RGB colour spaces are and the importance of using them correctly.

Why it matters in design

Had I seen the grey wall in person and not in an RGB converted colour space, I would have known to mix warm tones into my paints. The same theory applies when working in print. Converting an RGB image to CMYK during the printing process can lead to colour alteration and a loss of vibrancy. By working in a CMYK colour space and assigning percentages of cyan, magenta, yellow and black to a colour, we can be sure it will print as we desire, no matter how it appears on screen.

Digitising the paint brush

I often think of the tubs of paint when working in book production at Hyphen. CMYK is just like paint. Colours are built in the same way. Using numbers keeps things consistent. Just in the same way one drop of blue paint will greenify a yellow, 1% of cyan goes a long way. By referring to the colour make-up, it is easier to build unified palettes that are high in contrast and/or sit harmoniously as a suite. Beyond building palettes, I apply the same thinking to every job I do in book production, editing photographs, choosing paper stocks and embellishments for a book’s cover. How do the various colours tie together, and where can extra drops or percentages be added to enhance the design?

Jane Heriot, Hyphen’s junior designer, is the creative force behind bold and colourful books like EastCoast Beverages’ and St Andrew’s School’s recent projects.