How do the eyes/brain perceive colour?

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The eye is made up of various receptors to perceive colour called rods & cones. There are over 120 million rods and 7 million cones in each eye.

 

Rods are more sensitive than the cones but they are not sensitive to colour, they perceive images as black, white and different shades of grey.

 

Cones contain one of three pigments sensitive to either RED GREEN or BLUE.

 

When light is reflected off a subject into your eye, the wavelengths of reflected light hit the light sensitive retina in your eye which is covered by these millions of light-sensitive cells (rods & cones) and stimulate these cells to varying degrees which sends a signal through your optic nerve into the cortex of your brain which work in combination with connecting nerve cells and give the brain enough information to interpret and name colors and familiar sensations of color to determines the colour of the subject.

 

64% of cones are Red Receptors which are sensitive to long wavelengths (red). One third of cones are Green Receptors which are are sensitive to middle wavelengths (green) and 2% of cones are Blue Receptors which are sensitive to short wavelengths (blue)

 

 

When each of these cones are stimulated at varying degrees they differentiate the colours as per below.

 

Red & Blue cones stimulated produces magenta light, (magenta is a secondary additive colour)

 

Red & Green cones stimulated produces yellow light, (yellow is a secondary additive colour)

 

Blue & Green cones stimulated produces cyan light, (cyan is a secondary additive colour)

 

Red, Green & Blue cones stimulated produces white light.

 

 

 

http://www.pantone.com/pages/pantone/Pantone.aspx?pg=19357&ca=29

 

 

http://www.livescience.com/32559-why-do-we-see-in-color.html

 

 

http://www.colourtherapyhealing.com/colour/colour_perception.php

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Colour Theory & Theorists – Additive Colour

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Additive colour is the colour effects of light directly from a light source. It starts with black and mixes red, green and blue light together to produce other colors.

RGB (Red, Green, Blue) Colour is another way of referring to additive colour. The most common example of additive colour process is colour a television screen or computer monitor.

 

RGB are the 3 primary colours and additive colour process mixes various amounts of red, green and blue light to produce other colours. Combining one of these additive primary colors with another produces the additive secondary colors cyan, magenta, yellow. The additive colour model image shown above is a good example of how additive colour is processed.

 

Where blue and green are combined the color cyan is produced

 

Where blue and red are combined the color magenta is produced

 

Where red and green are combined the color yellow is produced.

 

When the primary additive colours are combined (red, green and blue) produce what we perceive as white light.

 

 

 

http://www.youtube.com/watch?v=LCs8mK1rzc0

 

http://home.bway.net/jscruggs/add.html

 

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Colour Theory & Theorists – Subtractive Colour

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Subtractive colour, also know as CMY (Cyan, Magenta, Yellow) is a subtractive colour system which involves reflections or absorption of wavelengths of colour

and reflective light on an object such as paper that reflects back wavelengths of  white light that illuminates colorants such as pigments, dyes or inks to produce & reflect other colours to the viewers eye. The viewer (or detector) can be the human eye, film in a camera or a light-sensing instrument.

If an object reflects all the white light back to the viewer, it appears white. If an object absorbs (subtracts) all the light illuminating it, no light is reflected back to the viewer and it appears black. When combined in equal amounts, pure subtractive primary colors produce the appearance of black. It is the subtractive process that allows everyday objects around us to show color.

The printing process uses cyan, magenta and yellow (CMY) inks and a fourth ink, black which symbol is ‘K’. Overprinting one transparent printing ink with another produces the subtractive secondary colors, red, green, blue. Process printing inks are transparent. It is the paper that reflects unabsorbed light back to the viewer.

 

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Colour Theory and Theorists – Itten – Colour Contrasts

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Colour Theory and Theorists – Itten – Colour Contrasts

 

http://colorwheelco.com/colortheory/ittenscolorwheel.php

http://www.worqx.com/color/itten.htm

 

 

Johannes Itten developed a colour wheel consisting of twelve colours in which he separated into three categories: three primary colours, three secondary and six tertiary colours.

 

Primary Colors are the building blocks for all other hues, and cannot be created by mixing any other pigments. They are blue, yellow, and red.

 

Secondary Colors are each created from two of the primaries. They are orange, green, and violet.

 

Tertiary Colors are formed by mixing a primary and secondary color. They are yellow-green, yellow-orange, red-orange, red-violet, blue-violet, and blue-green.

 

Itten also created varied color combinations by using the hue’s contrasting properties and developed the ‘seven methodologies’ as below.

 

THE CONTRAST OF SATURATION

 

THE CONTRAST OF SATURATION

Contrast of saturation The contrast is formed by the juxtaposition of light and dark values and their relative saturation.

 

THE CONTRAST OF LIGHT AND DARK

THE CONTRAST OF LIGHT AND DARK

Contrast of light and dark The contrast is formed by the juxtaposition of light and dark values. This could be a monochromatic composition.

 

THE CONTRAST OF EXTENSION

THE CONTRAST OF EXTENSION

Contrast of Extension Also known as the Contrast of Proportion. The contrast is formed by assigning proportional field sizes in relation to the visual weight of a color.

 

THE CONTRAST OF COMPLEMENTS

THE CONTRAST OF COMPLEMENTS

Contrast of complements The contrast is formed by the juxtaposition of color wheel or perceptual opposites.

 

SIMULTANEOUS CONTRAST

SIMULTANEOUS CONTRAST

Simultaneous contrast The contrast is formed when the boundaries between colors perceptually vibrate. Some interesting illusions are accomplished with this contrast.

 

THE CONTRAST OF HUE

THE CONTRAST OF HUE

Contrast of hue The contrast is formed by the juxtaposition of different hues. The greater the distance between hues on a color wheel, the greater the contrast.

 

THE CONTRAST OF HUE - PRIMARIES

THE CONTRAST OF HUE – PRIMARIES

itten’s contrast of hue – primaries The contrast is formed by the juxtaposition of primary hues.

 

THE CONTRAST OF WARM AND COOL

THE CONTRAST OF WARM AND COOL

Contrast of warm and cool The contrast is formed by the juxtaposition of hues considered ‘warm’ or ‘cool.’

 

 

Colour Theory and Theorists – Munsell – Hue, Chroma and Value

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Albert Henry Munsell was an artist and professor who created an accurate system for numerically describing colors, now known as the Munsell Color System in 19898.  Using the previous colour theories Munsell extended the colour wheel into a three dimensional sphere to create a color space that specifies colors based on three color dimensions: Hue, Value & Chroma. Munsell determined the spacing of colors along these dimensions by taking measurements of human visual responses.

Munsell_3D

Hue – Is the specific colour measured by degrees around horizontal circles in the sphere

 

Value – Is the lightness or darkness of the colour measured vertically from 0 (black) to 10 (white) of the sphere.

Chroma  – Refers to the intensity or purity of colour or the dullness (saturation) measured radially outward from the neutral (gray) vertical axis of the sphere

Colour Theory and Theorists – Goethe – Psychology of Colour

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Colour Theory and Theorists – Goethe – Psychology of Colour

Johann Wolfgang von Goethe, was a German poet, artist, and politician who was influenced by Newtons Colour Wheel Theory to further explore the psychological impact that colour has on mood and emotion. In 1810 Goethe published “Theory of Colours”, his doctrine of colours focused more on using language to describe the influence colours generate when our brain interprets color and how color combination create a certain feeling & atmosphere within the viewer. Goethe theories were human-orientated and based more on sensation than Science.

His first philosophy of colour was that Humans naturally find examples in nature to represent that colour and make sense & use of it.

In the second category, first, he suggested the concept of

Goethe also had a concept of ‘positive & negative’ colours. Positive being ‘warm’ colours and ‘negative’ being cool colours which create a certain atmosphere of either powerful, gently & radiant.

These are quotes taken from his book “Theory of Colours” on how certain colours can be perceived and create emotion and atmosphere.

Yellow

In its highest purity it always carries with it the nature of brightness, and has a serene, gay, softly exciting character.

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Red – Yellow

The red-yellow gives an impression of warmth and gladness, since it represents the hue of the intenser glow of fire.

Yellow – Red

In looking steadfastly at a perfectly yellow-red surface, the colour seems actually to penetrate the organ. It produces an extreme excitement, and still acts thus when somewhat darkened. A yellow-red cloth disturbs and enrages animals. I have known men of education to whom its effect was intolerable if they chanced to see a person dressed in a scarlet cloak on a grey, cloudy day.

Blue

This colour has a peculiar and almost indescribable effect on the eye. As a hue it is powerful — but it is on the negative side, and in its highest purity is, as it were, a stimulating negation. Its appearance, then, is a kind of contradiction between excitement and repose.

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Red- Blue

Blue deepens very mildly into red, and thus acquires a somewhat active character, although it is on the passive side. Its exciting power is, however, of a different kind from that of the red-yellow. It may be said to disturb, rather than enliven.

Blue – Red

This unquiet feeling increases as the hue progresses, and it may be safely assumed, that a carpet of a perfectly pure deep blue-red would be intolerable. On this account, when it is used for dress, ribbons, or other ornaments, it is employed in a very attenuated and light state, and thus displays its character as above defined, in a peculiarly attractive manner.

Red

The effect of this colour is as peculiar as its nature. It conveys an impression of gravity and dignity, and at the same time of grace and attractiveness.

red lips

Green

The eye experiences a distinctly grateful impression from this colour. If the two elementary colours are mixed in perfect equality so that neither predominates, the eye and the mind repose on the result of this junction as upon a simple colour. The beholder has neither the wish nor the power to imagine a state beyond it.

Bowling green grass background.

Colour Theory and Theorists – Isaac Newton – Prism Theory

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In 1666, Sir Isaac Newton, a mathematician and physicist  passed a beam of sunlight through a glass prism producing the visible colour spectrum of the rainbow on a wall.

To dispute the claim that the colour existed from the glass of the prism, Newton then projected light through a second prism to create white light thus observing that colour is a property of light and white is a mixture of all colours. This experiment concluded that the colour spectrum projected is the result of the prism interacting with already-coloured light rather than prism generating the colour itself.

 

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