New Laws of Simultaneous Contrast?

Abstract

Drawing on many seemingly disparate and unrelated lines of evidence, we argue that the direction of the simultaneous contrast effect in three-dimensional colour space is given by the difference vector between target and surround ('direction hypothesis'). This challenges the traditional idea according to which the direction of the simultaneous contrast is complementary to the colour of the surround ('complementarity law'). We also argue that the size of the simultaneous contrast effect is either constant or decreases with the difference between target and surround in three-dimensional colour space. The latter proposal challenges Kirschmann's fourth law. Within our theoretical framework, the universally presumed validity of the complementarity law and Kirschmann's fourth law can be understood as resulting from the failure to take various confounding factors into account when interpreting empirical data, the most prominent of which is the influence of temporal von Kries adaptation.

Transparency perception: the key to understanding simultaneous color contrast

“…This assumption, which is known as Kirschmann's fourth law [20,21] is readily compatible with the traditional explanation of simultaneous contrast in terms of color constancy. As we have shown, however, the widespread belief in the validity of this law is presumably due to the failure of taking various confounding factors into account [10]. If this is done, the available empirical evidence suggest instead that the magnitude of the simultaneous contrast effect decreases with the difference between the colors of the target and the surround (inverse size law [10]), which is not easily understandable based on the traditional explanation of simultaneous contrast.…”

“…2. From the above it is clear that the transparency theory explains the converging lines of empirical evidence for the direction law reviewed more comprehensively in [10]. What can be said about the magnitude of the simultaneous contrast effect?…”

“…For this reason, it has been believed that the gamut expansion effect is a new kind of simultaneous contrast effect due to visual mechanisms distinct from those underlying the classical simultaneous contrast effect [2,5,8,9]. Drawing on many different lines of converging evidence, however, we have recently argued that classical simultaneous contrast and the gamut expansion effect both obey the direction law and are best regarded as different names for the same basic phenomenon [7,10,11]. According to our argument [10], the widespread belief in the complementarity law is due to a failure to take various confounding factors into account when interpreting empirical data, the most prominent of which is the influence of temporal von Kries adaptation (which actually does obey the complementarity law to a fair approximation).…”

“…Drawing on many different lines of converging evidence, however, we have recently argued that classical simultaneous contrast and the gamut expansion effect both obey the direction law and are best regarded as different names for the same basic phenomenon [7,10,11]. According to our argument [10], the widespread belief in the complementarity law is due to a failure to take various confounding factors into account when interpreting empirical data, the most prominent of which is the influence of temporal von Kries adaptation (which actually does obey the complementarity law to a fair approximation). From this perspective, the kind of display used to demonstrate the gamut expansion effect ( Fig.…”

Basic Characteristics of Simultaneous Color Contrast Revisited

“…Accordingly, when interpreted as a description of the simultaneous contrast effect, it must necessarily be regarded as a crude approximation. As discussed in Ekroll and Faul (2012), a function similar to the one shown in Figure 6b, but with a step discontinuity at zero rather than the smooth transition connecting the positive and negative branches, may be more adequate.…”