Additional Info

• ID Code: O1-31
• Purpose: Demonstrate Mach bands.
• Description: Cast a shadow of a row of lights onto a sheet of light paper or folded cardboard. The photograph at the right shows shadows from a series of goose-neck lamps with the inside of the lamps painted black to provide a more effective point source. Although the illuminantion of the series of gray areas is actually constant for each area, the phenomenon of simultaneous contrast in the eye causes the area to look darker adjacent to a lighter area and lighter adjacent to a darker area.
• Availability: Available
• References: REFERENCES: (PIRA unknown.) See Demonstration Reference File for further information about this phenomenon. See also demonstration O4-22 CORNSWEET ILLUSION.
• Loc codes: O1, N3