Image colour lecture

C O L O U R

MONOCHROMATIC

Emphasize form, light and texture

ANALOGOUS

Little energy - sit easily together without tension.

COMPLIMENTARY

extreme chromatic contrast and LOTS of energy

COMPLIMENTARY PROPORTION

SPLIT COMPLIMENTARY

TRIADIC

TETRADIC

92

93

Any colour space (film, computer graphics, print etc) is a representational system that is designed to

mimic our human perception of vision

Accurate colour measurement begins with measure of light intensity - linear to light (not linear to our

perceptual system)

These values are then subjected to a ‘Gamma Correction’ so that the image mimics the perceptual

response of our eyes

Human vision is more sensitive in the ‘shadows’ than in the ‘highlights’

93

Other Colour Spaces

CMYK

H

RGB Colour SpaceAdditive

Other Colour Spaces

CMYK

H

CMYK Colour SpaceSubtractive

96

RGB - 8 bit colour spaceeg. Photoshop

3 x 8 bit colour channels (3 bytes)0 - 255 codes per channel

(0, 0, 0) = black(255, 255, 255) = white

over 16 million colours represented

96

97

CIE Colour Space

98

Colour Gamut

RGB Colour Space

99

100

Trichromacy Eye senses colour through rod and cone cellsFovea - responsible for sharp central vision

Cone cells - concentrated at the fovea- 6 million cone cells in a human eye- three types of cone cells- Red, Green and Blue colour receptors (or long, medium and short wavelengths of light)The brain combines the information of each of the receptors to create perception of colour

Rod Cells - more sensitive to light- 120 million rod cells in a human eye- concentrated at edges of retina- 100 times more responsive than cones so used for night vision- have little role in colour vision

100

101

102

103

104