Color Vision

Topic 2: History of Color Vision

About the AuthorProfessor: CambridgePresident: International Color Vision Society (ICVS)Research interests • visual perception of colour, motion, form and depth • genetic basis for individual variations in perception• nature of the information carried by the cerebral bus • history of neuroscience and of colour theory

A few terminologiesVisible spectrumTrichromacy:Color mixtureColor matchingColor constancy

Electromagnetic Spectrum

Electromagnetic Spectrum

Visible Spectrum

Light Behavior & Color

Absorb and Reflect

Additive & Subtractive Color Mixture

Additive – the wavelengths add to each other!

More light reflected!

Subtractive mixture – paints, ink or color filter

More light absorbed, so less reflected!

Additive & Subtractive Color Mixture

Color Matching

Red (700 nm)

Green (546 nm)

Blue (436 nm)

rR + gG + bB mM

Trichromacy: Given three different colored lights of variable intensities, it is possible to mix them so as to match any other test light of any color.

Test fieldMatching field

Chromatic Discrimination

Color Constancy

perceived color of objects remains relatively constant under varying illumination conditions