The watercolor effect: Quantitative evidence for luminance-dependent mechanisms of long-range color assimilation

Frédéric Devinck, Peter B. Delahunt, Joseph L. Hardy, Lothar Spillmann, John S Werner

Research output: Contribution to journalArticle

35 Scopus citations


When a dark chromatic contour delineating a figure is flanked on the inside by a brighter chromatic contour, the brighter color will spread into the entire enclosed area. This is known as the watercolor effect (WCE). Here we quantified the effect of color spreading using both color-matching and hue-cancellation tasks. Over a wide range of stimulus chromaticities, there was a reliable shift in color appearance that closely followed the direction of the inducing contour. When the contours were equated in luminance, the WCE was still present, but weak. The magnitude of the color spreading increased with increases in luminance contrast between the two contours. Additionally, as the luminance contrast between the contours increased, the chromaticity of the induced color more closely resembled that of the inside contour. The results support the hypothesis that the WCE is mediated by luminance-dependent mechanisms of long-range color assimilation.

Original languageEnglish (US)
Pages (from-to)1413-1424
Number of pages12
JournalVision Research
Issue number11
StatePublished - May 2005



  • Assimilation
  • Color spreading
  • Long-range interactions
  • Watercolor effect

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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