In this tutorial I will try to explain the basic rules of working with colour. Heh, that's a really tough task, so be understanding and gentle ;). I urge anyone that reads this article to paint and make observations as you go along, even copy the images as closely as possible to learn. Have fun. That's, what's Art about.
Part 1 : "RGB" - what's that?
The RGB stands for "Red, "Green" and "Blue", the main colours in the palette. By mixing these colours you can achieve thousands of colours. The standard is used in TV's and monitors for example. It's used for any imaging device that has a screen. There are also other standards, like CMYK (Cyan, Magenta, Yellow, blacK) but this one for ex. is used for printing. But the most common standard is RGB and this is what we'll talk about.
The white sun light is made of different colours, it's not really white; when you throw the sunlight thru the prism or thru the drops of water (a rainbow), the light will split to all the colour components of the light - that is Purple, Red, Yellow, Green, Blue Cyan, Dark Blue. Newton and Young made experiments, that prove this fact. And it was Young that proved, that the amount of the components can be diminished to three - Red, Green and Blue, that we will call Secondary colours. Those three colours allowed Young to recreate the White light. The Primary colours (Purple, Yellow, Cyan) are made by mixing the Secondary Colours. Mixing Primary with Secondary colours will give us Thertiary colours, and so on and so forth...
(on the illustration - P-Primary colour, S - Secondary, T - Tertiary)
Part 2 : Mixing Colours - live (Read only when you painting with real paints or want use mixer in Painter)
Yeah, you say, I mix red, green and blue paint and all I get is black. Yes, when we mix paints we will not get a brighter colours as it happens with the light (Synthesis by Addition), but darker.
(mixed red, green and blue colours in Painter)
This is called Synthesis by Substraction. It works like that - when you mix cyan with yellow, you get green, because when the light is cast on it, the cyan substracts red, the yellow substracts blue... and comes out green (image 2, bottom) when the white light is cast on the mix. In spotlights when you mix red with green - you'll get yellow, because is adds one to another ( image 1 - middle left ). This info is usefull, when you have to light some scene in a theatre or 3D.
(1 - Synthesis by Addition; 2 - Sythesis by Substraction)
By understanding it we can simulate the natural colours of the world, when painting non-digital.
Part 3 - Filling colours
That's always a problem - what colour put next to another so that it looks good? This is a task for a lot of time, mainly learning by your own experience, BUT... there is a very simple rule that covers it - when you take a colour wheel, the filling colours lie opposite each other (yellow - deep blue, red - cyan etc).
By understanding it and using it well you can create very intensive shadows and background and create amazing contrasts.
(Henri Matisse - "Mrs Matisse Portrait" - here is a perfect example of using filling colours, that make maximum contrasts - see part 4)