COLOR Perception

1. COLOR Perception Sam Francis, Three Colors

2. The Three Color Systems: • Additive (light-based), also known as RGB color • Subtractive (pigment based) • Process (Printing-based) CMYK color

3. An Additive, or Light-based color system, where the three primaries create white

4. Primaries and Secondaries in a light-based system, where Red, Green, and Blue Make magenta, yellow, and cyan, and finally, white.

5. Traditional, Pigment-based Primaries

6. Primary colors in the CMYK (printing and photo) system

7. We see color when light wavelengths are interrupted by matter. In the case of a green leaf, all colors in sunlight are absorbed into the leaf except for green, which is reflected toward our eyes. If all wavelengths are absorbed we see black. If all wavelengths are reflected we see white.

8. How the human eye perceives color

9. Basic Diagram of the human eye

10. Rods: perceive value and movement only. They allow us to perceive forms (but not colors!) in all light situations, including dim light. Cones: perceive color. They require a brighter lighting situation to function. This is why we don’t see colors as well at night. This is also why squinting can help to determine what color is lower in value---squinting allows less light to pass through our eyes, limiting the effects of the cones, and our ability to read color. When squinting, only rods are working, so we are able to focus on value better. We have 100million rods and 6million cones.

11. Two theories of how colors are perceived. • Trichromatic theory: states that there are three different kinds of cones, one for red, one for green, and one for blue-violet (this roughly corresponds to the primaries in the additive color system).

12. We see all colors through variations in the amounts of these cones that are stimulated. For example, when perceiving yellow, the red and green cones are activated • Remember, in the additive color system, red and green mix to create yellow.

13. Theory two • Opponent-process theory: according to this theory, colors are discerned through cone pairs of opposing colors. • Pairs of cones will perceive red and green OR Blue-violet and Yellow. • In each pairing, only one color can be seen at a time and the other is inhibited.

14. After-Images • This theory may explain the phenomena of After-Images, where, if you focus on an area of saturated color for a long time and then move your eyes, you will briefly see the complement (according the the subtractive color wheel) of that color. • When we focus on a red apple, our red cones are activated and our green cones are suppressed • The theory suggests that when a cone is fatigued from focusing on a strong, dominant color, it’s opposite is no longer suppressed, and is spontaneously generated.

17. AFTER IMAGE: when the signaling mechanism for one color is fatigued, its complimentary is no longer inhibited.

19. After Image is also known as ‘Successive Contrast’

20. FACTORS INFLUENCING COLOR PERCEPTION: • Amount and quality of lighting on surfaces • Visual health/condition of color blindness or other color abnormalities • The surface of the object: shiny, matte, textured • The amount of a color • Color relationships: how color is affected by its surroundings

21. Abnormal color perception/perception deficiencies

22. The Ishihara Color test is a tool used to diagnose color blindness

23. Color-blindness occurs in about 7% of men and .04 % of women

24. Individuals will lack a type of cone and thus be unable to perceive the color associated with that cone

26. http://prometheus.med.utah.edu/~bwjones/2013/12/color-blindness-what-does-it-look-like/http://prometheus.med.utah.edu/~bwjones/2013/12/color-blindness-what-does-it-look-like/

27. Synesthesia is a perception abnormality where people respond to the environment by combining senses. Shapes may have taste, sounds or scents may trigger color.These colors are actually perceived in response to sound, smells, etc.

28. Grapheme Synesthesia • Letters and numbers have inherent color associations

29. Chromesthesia • Sounds or musical tones trigger shapes and colors that fade once the sound ends

30. Wassily Kandinsky, 20thc Russian painter and synesthete

31. The surface of the object: shiny black satin vs. matte velvet.

32. The amount of a color, colors typically seem more intense/vibrant in smaller amounts

33. The environment surrounding a colorThe center stripe is actually one single value.

35. Different temperatures of light will change our perception of colors

36. CLAUDE MONET 3 VIEWS OF ROUEN CATHEDRALMonet famously painted over 30 versions of this cathedral, exploring how light at different times of day changed his perception of the colors. Early morning midday sunset

37. Metamerism • The capacity of colors to change under different lighting situations

38. Color Constancy • The idea that we tend to perceive colors as unchanging, because of our visual memory of objects. Our brains are able to compensate for color changes that occur due to changing light situations.

39. LOCAL COLOR:the general color of an object

40. Simultaneous Contrast • How colors may be effected by color relationships or color environment. Because a color is rarely seen in isolation, the surrounding colors will influence, and often change the color perceived. Richard Anuszkiewicz

41. Michel Eugene Chevruel-first discovered simultaneous contrast • A French chemist in the 1830s who was developing dyes for textiles. • He discovered that his dyes seemed to be one color when seen in isolation, but often read as a completely different color when used within rugs or patterns

42. Josef Albers Homage To the Square

44. Illusion of two colors looking like one color

45. Why does this happen? Two colors look like one color

46. Examples of simultaneous contrast by: 1.Value contrasts 2.Complementary reaction 3. Subtraction

47. Subtraction Effect: A dominant color may seem to subtract itself from a less dominant color-- a yellow environment causes a smaller yellow-green square to seem more green because it seems to subtract the yellow from the yellow- green. In contrast to pure yellow, it is more difficult to notice the yellow in yellow-green.

49. What effect do the background squares have on our perception of the center square?

50. Complementary Reaction/Effect • A dominant color may seem to make a less dominant color resemble it’s complement. A strong orange environment causes a blue-green square to seem bluer. This is related to the after-image effect where our eyes become fatigued by one color and spontaneously create it’s opposite.