49 While studying white light reflecting off prisms, Sir Isaac Newton, the famous mathematician, noticed that the light reflected a spectrum of colours and invented the first colour wheel. See unit 1.2 to see what warm and cool colours represent. COLOURS The colour wheel All the main theories of colour start from a six-point colour wheel made up of three primary colours (red, yellow, and blue), and three secondary colours (orange, green, and purple), which derive from a combination of two primary colours. An imaginary line splits the wheel into warm colours (red, orange, and yellow), and cool colours (blue, green, and purple). Tertiary colours are the merging of primary and secondary colours , and more colours are created in the same way in an endless number of mixtures. Black, white, and grey are considered neutral colours, even though black is sometimes considered as the absence of colour and white as the blending of all colours. Hues, shades, tints, and tones By adding black and white to a colour (general term) or hue the dominant colour family on the colour wheel hundreds of more colours can be created: a tint refers to a colour to which some white has been added; What are the six tertiary colours? 126 LayOut a tone refers to a colour to which grey (i.e. both black and white) has been added. Colour harmonies In order to design a successful layout, it is necessary to pay attention to the various combinations of colour, looking for harmonies of colours: monochromatic colours refer to the different shades, tints, and tones of a single hue; complementary colours are the ones which are opposite a colour in the chromatic wheel; split-complementary colours include a colour and the two colours beside its complement; analogous colours are the two colours which are right next to a colour in the colour wheel; triadic/square colours are three/four colours that are equally spaced out on the colour wheel; tetradic or rectangle colours are two complementary colour pairs. COLOUR HARMONIES Complementary hue: gradazione di colore merging: fusione shade: sfumatura to split: dividere tint: tonalit chiara tone: tonalit scura a shade refers to a colour to which some black has been added; Triadic Split-complementary Tetradic Square Analogous Monochromatic