Eye is NOT a light meter
–Designed to detect CHANGES
–Not good for detecting Absolute Values
–Designed to extracts Surface Information
–Discounts Illumination Level & Color of
Illumination
–Sensitive over 9 orders of
magnitude
Mechanisms
1Adaptation
–Receptors
bleach and become less sensitive with more light
–Takes
up to ½ hour to recover sensitivity
–2 Simultaneous Contrast