A new effect in the domain of lightness has been observed. When two identical middle gray squares are placed at the center (respectively white or black) of two crosses, the first cross having arms filled by a constant achromatic gradient from black (outer part) to white (inner part), while the second cross is the negative of the first one, the gray target surrounded by white appears much darker than that surrounded by black. Preliminary observations showed that, in a simultaneous comparison, this phenomenon is much stronger than the classical lightness contrast effect that is generally weak (for a review of the literature about the magnitude of the contrast effect see Agostini & Bruno, 1996, Perception & Psychophysics, 58, 250-258). A possible way to account for the new lightness effect is to assume that the gradient is perceived as a change of the level of illumination rather than as a change of the reflectance of the surfaces.

A new effect of gradient on lightness

GALMONTE, Alessandra
1997-01-01

Abstract

A new effect in the domain of lightness has been observed. When two identical middle gray squares are placed at the center (respectively white or black) of two crosses, the first cross having arms filled by a constant achromatic gradient from black (outer part) to white (inner part), while the second cross is the negative of the first one, the gray target surrounded by white appears much darker than that surrounded by black. Preliminary observations showed that, in a simultaneous comparison, this phenomenon is much stronger than the classical lightness contrast effect that is generally weak (for a review of the literature about the magnitude of the contrast effect see Agostini & Bruno, 1996, Perception & Psychophysics, 58, 250-258). A possible way to account for the new lightness effect is to assume that the gradient is perceived as a change of the level of illumination rather than as a change of the reflectance of the surfaces.
1997
luminance gradients; illumination; lightness
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/306190
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact