Which of the following is NOT one of Grassman's Law for metamers?

The concept of Grassmann's Law is essential for understanding color perception and how different color stimuli can produce the same perceptual experience, known as metamerism. Metamers are color stimuli that are physically different but are perceived as identical by the human visual system.

The assertion that metamers may only be present for dichromatic patients is not valid within the principles outlined by Grassmann's Law. Metamers can occur in individuals with normal trichromatic vision, meaning they can perceive various combinations of colors as the same even if they are derived from different spectral compositions. This phenomenon is not limited to those with color vision deficiencies, such as dichromatic individuals, but is a fundamental aspect of color vision applicable to everyone with normal vision.

In contrast, the other principles of Grassmann's Law—concerning the addition of equal amounts of light, adjustments in intensity, and transitive relationships between sets of colors—are indeed fundamental characteristics of metamerism. These principles explain how light stimuli can interact without altering the perceived color, highlighting the system's reliance on the human visual response to various wavelengths, regardless of variations in actual stimulus composition. Thus, the option related to dichromatic patients does not reflect the comprehensive nature of metamerism as defined by Grass