The document discusses colour theory, including the origins and perception of colour, light decomposition, and how the colour of objects is determined by light absorption and reflection. It covers hue, saturation, value, additive and subtractive colour mixing, primary and secondary colours, complementary colours, and limitations of three-colour mixing systems. Optical colour mixing through pointillism and layering of transparent colours is also summarized.

1. Colour Theory Origins of Colour

2. Colour Colour is not a characteristic of an image or object. It is rather a personal and subjective appreciation. It can be defined as a sensation or feeling that is produced in response to eye stimulation and its nervous mechanisms, due to the luminous energy of some waves’ lengths.

3. Decomposition of White Light Light Infraredsrrojos Red Orange Yellow Yellow-Green Green-Blue Blue Violet Ultraviolets Prism

4. The colour of an object Objects have the property of absorbing a determined amount of light and to reject another amount. An object’s natural colour is given by the ray of light that it has rejected.

5. The colour of an object Black Absortion Grey Parcial Reflection

6. The colour of an object

7. Theory of Colour Colour Properties

8. Hue It’s the pure state of colour, without adding black or white, and it’s an attribute associated with the length of the dominant wave in the mixture of luminous waves. The hue is defined as an attribute of colour that allows us to distinguish red from blue, and it refers to the path one tone follows from one side to the other in the chromatic circle. This is why yellow green and blue green are different hues of green.

9. Saturation or Intensity Also called Croma, this concept represents the purity or intensity of a particular colour, its liveness or paleness, and it can be related to the broad of the band of light that we are visualizing. Pure colours of the spectrum are fully saturated. An intense colour is very vivid. The more saturated a colour is, less will be the feeling of movement of the same object.

10. Value or Tone A term used to describe how light or dark a colour might seem, and it relates to the amount of light perceived. The shine might be defined as the amount of “darkness” a colour has, this is, it represents how light or dark a colour is with respect to its pattern. This is an important property, because it will create spacial sensations through colour. Therefore, portions of the same colour with strong differences in value (value contrast) will define different portions in the space, whereas a gradual change in a colour’s value (gradation) will give the feeling of outline, of the continuity of an object in space.

11. Theory of Colour Colour Mixture

12. Mixing Colours There are two ways of mixing colours: Additive mixture: Mixing with colours’ lights. More colours = more luminosity Sustractive mixture: Mixing paint. Light: Taking ut the light. The mixed colour is always darker than the lightest of the colours that were previously mixed. Each pigment absorbs a part of the spectrum. If we mix colours, different sections of the spectrum will be absorbed.

13. Three Colours’ Mixing System Mixing the primary / secondary colours They are called primary colours because they can’t be obtained by mixing other colours. When we mix primary colours we can obtain all colours. Primary Colours Secondary Colours Lemon Yellow Green Cyan Violet Magenta Orange CYAN + LEMON YELLOW VERDE BLUE + RED VIOLET MAGENTA + YELLOW NARANJO LEMON YELLOW GREEN ORANGE CYAN BLUE VIOLET MAGENTA RED When you mix primary colours, they anull themselves.

14. Three colours’ mixing system Secondary /Terciary Colours Secondary Terciary Violet + Orange Violet + Green Orange + Green When you mix secondary colours they don’t annul themselves completely. The primary colour that dominates the mixture determines the resulting colour.

15. Three colours’ mixing system Complementary Colours Red (Magenta) Green Blue (Cyan) Orange Yellow Violet

16. Mezclando colores para conseguir negro Yellow + Magenta + Cyan Cyan + Orange Yellow + Violet Magenta + Green Primary Colours Complementary Colours

17. Mizing colours to obtain black Violet + Orange Violet + Green Orange + Green If we mix secondary colours we won’t obtain black. If we mix terciaries we obtain black.

18. Three colours’ mixing system PRIMARY COLOURS YELLOW CYAN MAGENTA SECONDARY COLOURS YELLOW+CYAN YELLOW+MAGENTA CYAN+MAGENTA GREEN ORANGE VIOLET TERCIARY COLOURS GREEN+ORANGE GREEN+VIOLET ORANGE+VIOLET

19. Three colours’ mixing system To obtain black: WE need the three primary colours Mixing three primaries. Mixing complementaries. Mixing the three terciaries. Black+White Grey

20. If we mix colours which are next to each other we will obtain 6 new colours. If we do the same process again, we will get 24 colours. Three colours’ mixing system Mixing primaries and secondaries different tones

21. Limitations of the three colours’ mixing system (pigments) Lemon Yellow-Cyan-Magenta Lemon yellow contains little amounts of blue. Cyan contains little amounts of yellow. Magenta contains little amounts of cyan.

22. Limitations of the three colours’ mixing system Violet Cyan + Magenta (yellow) (cyan) Yellow and Violet Complementaries Less saturated violet Orange Lemon Yellow + Magenta (cyan) (cyan) Orange and Blue Complementaries Less saturated orange Green Cyan + Lemon Yellow (yellow) (cyan) Saturated Green

23. Six colours’ mixing system It is used due to colours’ saturation problems. If we add: Ultramarine blue that contains little amounts of red. Cadmium Yellow that contains little amounts of red. Bermellion Red that contains little amounts of yellow. Violet Orange Magenta Blue Ultramarine Yellow Bermellion (cyan) (red) (red) (yellow) (in small amounts) Saturated Violet Saturated Orange

24. Advantages of the six colours’ mixing system Resulted colours are closer to black. More combination possibilities: colours can be mixed in different proportions This determines Tone When you mix all colours you obtain a grey that is very close to black. When you mix colours in different proportions you obtain different greys.

25. Theory of Colour Optical Mixtures of Colours

26. Optical Mixture of Colours Puntillismo : Painting with dots To obtain green we do not need to mix the paint, we can paint yellow and blue dots close to each other and that will give the impression of green. The smaller the dots, the more complex the mixture might be perceived. (il.11) Colours+white, grey and black Saturation and luminosity Optical black

27. Optical Mixture of Colours Transparencies Aplication of transparent layers of paint. Ej.: aquarela Transparent blue yellow green Transparente red yellow orange Transparent blue red violet If we mix 3 colours one on top of the other, They anull each other and You obtain an optical mixture se consigue una mezcla óptica unsaturated grey ( ill. 14). The best results are obtained starting with lighter colours and placing darker colours on top of them.