Within the philosophy of color, there is a dispute between color realism, the view that colors are physical properties that objects possess, and color fictionalism, a species of error theory viewing colors according to which there are no such physical properties that objects possess.
One of the topics in the philosophy of color is the problem of the ontology of color. The questions comprising this field of research are, for example, what kind of properties colors are (i.e. are they physical properties of objects? Or are they properties of their own kind?), but also problems about the representation of colors, and the relationship between the representation of colors and their ontological constitution.
Within the ontology of color, there are various competing types of theories. One way of posing their relationship is in terms of whether they posit colors as sui generis properties (properties of a special kind that can't be reduced to more basic properties or constellations of such). This divides color primitivism from color reductionism. A primitivism about color is any theory that explains colors as unreducible properties. A reductionism is the opposite view, that colors are identical to or reducible to other properties. Typically a reductionist view of color explains colors as an object's disposition to cause certain effects in perceivers or the very dispositional power itself (this sort of view is often dubbed "relationalism", since it defines colors in terms of effects on perceivers, but it also often called simply dispositionalism - various forms of course exist). An example of a notable theorist that defends this kind of view is the philosopher Jonathan Cohen.
Another type of reductionism is color physicalism. Physicalism is the view that colors are identical to certain physical properties of objects. Most commonly the relevant properties are taken to be reflectance properties of surfaces (though there are accounts of colors apart from surface colors too). Byrne, Hilbert and Kalderon defends versions of this view. They identify colors with reflectance types.
A reflectance type is a set, or type, of reflectances, and a reflectance is a surface's disposition to reflect certain percentages of light specified for each wavelength within the visible spectrum.
Both relationalism and physicalism of these kinds are so called realist theories, since apart from specifying what colors are, they maintain that colored things exist.
Primitivism may be either realist or antirealist, since primitivism simply claims that colors aren't reducible to anything else. Some primitivists further accept that, though colors are primitive properties, no real or nomologically possible objects have them. Insofar as we visually represent things as colored - on this view - we are victims of color illusions. For this reason primitivism that denies that colors are ever instantiated is called an error theory.