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What is Colour?
Transcript of What is Colour?
Objects themselves do not actually have color, they only give off light that appears to have color.
Color vision is a combination of:
1) Light’s physical properties
2) The retina’s physiological response
3) The neural processing done by the brain 1. Visual perception of color is based on the physical composition of light waves.
Visible light is part of the electromagnetic spectrum that the human eye is capable of seeing.
Humans can detect a small amount of wavelengths ranging between
380nm to 760nm (between UV and infrared). 2. The human capacity for color vision is due to the retina consisting of 2 types of light-sensitive receptor cells- rods and cones.
Rods: -used for low light settings
-by themselves would only allow humans to see in black and white
Cones: -important for color vision
- 3 types of cones, each responsive to regions of the visible spectrum known as red, green and blue.
All light, no matter how complex, is reduced into 3 color components and sent to the brain through the optic nerves. 3. The brain then processes the information and results in your perception of color. This highly complex process allows humans to distinguish as many as 10 million different colors. Additive & Subtractive Color Systems Additive:
-Primary colors are red, green and blue
-When primary colors are projected together, they are perceived as white
-Consists of colors generated by all light dependent formats (ex. Computer
monitors, photography, TV) Subtractive:
-Used in the mixing of paints, dyes, inks
-2 systems: for painters and for printers
Painters have primary colors red, yellow, blue
Printers have primary colors cyan, magenta, and yellow Physiology of Color Vision-
2 Theories: Young-Helmholtz’s Trichromatic Theory:
1. The trichromatic theory holds that there are 3 types of photoreceptors in the eye: red, green and blue that detect certain wavelengths Hering's System of Color Opponency
2. The system of color opponency theory explains why the afterimage for red is green and for blue is yellow (and vice versa).
This suggested that there were 6 primary colors detected by 3 pairs of opponents- red/green, blue/yellow, and white/black.
Any receptor that was turned off by one of these colors, was excited by its coupled color. Color Blindness:
Some people have a deficiency called color blindness where they cannot perceive certain colors. Color blindness is generally inherited or based on genetic factors. Sometimes one can obtain color blindness through eye, nerve or brain damage, or over-exposure to certain hazardous chemicals. Color blindness is more common in males (5-8%) as opposed to females (roughly 1%). The most common form if color blindness is the inability to perceive red and green. The rarest is where no color is perceived and the world is in greys. Blind Spot: The blind spot is the area at the back of the retina where the optic nerves are located. There are no cones or rods in this area, and no light is detected. History of Color Theory
Two dramatically different aspects of colour have been studied. •Actual physical properties of colour •The ways in which human beings perceive and experience it Aristotle (384–322 BC)
•He is often considered the grandfather of colour theory.
•De Coloribus (On Colour)
•All colours were derived from mixing of light, such as sunlight or firelight and darkness or lack of light.
•Colours were arranged tonally, mirroring aspects of the natural world.
•White --> Yellow = Daytime--> Red = Setting sun--> Blue & Black = Night Sir Isaac Newton (1642–1726)
• In the 18th century, he discovered the physical properties of colour.
• His conclusion: Colour is in the light, not in the glass, and white light is a mixture of all the colours in the visible spectrum. Opticks:
• Identified the spectrum’s colours as red, orange, yellow, green, blue, indigo, and violet, and they were laid out in a circle, which was the first colour wheel. Johann Wolfgang von Goethe (1749–1832)
•Theory of Colours
•His colour wheel was based on the triad of the primaries (yellow, red, and blue), which when combined, produced the secondaries (green, violet, and orange).
•He assigned such colours to categories, such as ‘powerful’, ‘gentle’, and ‘radiant’ and ascribed to them qualities, such as nobility or sadness. Michel Eugene Chevreul (1786–1889)
•Principles of Harmony and Contrast of Colours
•The Law of Simultaneous Contrast – ‘Two adjacent colours, when seen eye by the eye, will appear as dissimilar as possible.’ Ewald Hering (1834–1918)
•On the Theory of Sensibility to Light:
The system of colour opponency states that there are six primary colours, coupled in three pairs: red-green, yellow-blue, and white-black.
The leading theories developed by Thomas Young and Hermann von Helmhotz, which stated that the human eye perceived all colours in terms of the three primaries of red, green, and blue. Wilhelm Ostwald (1853–1932)
• All colours were a combination of hue, white, and black, his 24-section colour cone extended from the graduating percentages of hue, white, and black.
• Tinting = + white, Shading = + black
• Some colour combinations are more harmonious than others led to his attempting to create harmonious relationships through a systematic colour order. Johannes Itten of the Bauhaus School (1888–1967)
• He taught the basics of design and colour for Germany’s Bauhaus school innovative preliminary course.
• There were seven types of contrasts in colour: hue, light/dark, cold/warm, complementary, simultaneous contrast, saturation, and extension/proportion. The Art of Colour:
• A colour wheel with a central triangle of the primaries, surrounded by another triangle of their respective complements, and an outer circle of 12 primary, secondary, and tertiary hues. Josef Albers of the Bauhaus School (1888–1976)
• Interaction of Colour, published in 1963, deepened his exploration into colour reactions by developing a series of exercises that placed simple shapes, such as small coloured rectangles onto different coloured backgrounds.
• Students would ‘discover that certain colours are hard to change, and that others are more susceptible to change.’ Faber Birren (1900–1988)
•One Colour Circle, consisted of thirteen hues arranged in a circle.
•The central grey area was off centre because he used more warm colours than cool ones.
•The warmer colours are more useful to the artist/designer because of their dynamic and intense qualities. Contemporary Colour Systems
CIE (Commission Internationale de l’Eclairage)
•In the 1930s, it developed the universally recognized colour
•It has the ability to accurately and consistently match colours that have little perceptible difference and allowing for an objective standard that eliminates the problems of human interpretation and pigment degradation.
•It allows for both additive and subtractive mixes and uses measurements to determine hue, luminance (light intensity), and saturation or purity to determine the colour’s ‘chromacity.’ Albert Munsell (1882-1953)
-published Colour Notation (1905)
-The Munsell system was adopted by United States Bureau of Standards in the 1940s and is still used commonly today - five principle colours; red, yellow, blue, green, purple
- secondary/intermediate colours; yellow-red, green-yellow, blue-green, purple-blue, red-purple
- arranged the 100 colours of the system using hue (pure spectrum colors), value (brightness), and chroma (gradations of saturation)
- gave them all separate numerical notations
- system is often arranged in a ‘tree’-like diagram with all the different variables crossing through the trunk.
Here is a 3D diagram of what the system would look like, and then a 2D diagram. Munsell system advantageous because it shows that not all hues are saturated to the same degree Pantone: Pantone Colour Matching System (PMS, but the good kind!)
- created in 1962 in the United States
- no theoretical model, but it is the standard for graphic design, the offset printing industry, and the interior and exterior paint market
- palette of 1114 colours; includes fluorescents and metallics
- many Pantone colours can be reproduced using the four-ink CMYK process, however the ones that are outside the CMYK gamut use a 13 base pigment system
- colours are identified as numbers e.g. the canadian flag red is PMS 032 NCS: Natural Colour System
-created in Sweden and used in many countries so that people would not have to refer to measurements, samples or comparisons to identify a colour
- imitates Hering’s opponent theory; colour as it percieved by the brain, based on the six elementary colours (white, black, red, yellow, green and blue)
- has 9 hues between primaries
- colours defined by 1) blackness (darkness), 2) chromaticity (saturation), 3) hue THE END