The architecture of light: architectural lighting design concepts and techniques. A textbook of procedures and practices for the architect, interior designer and lighting designer pdfdrive com

Figure 6.4 The effect of an isolated wavelength of visible light can be determined by identifying where it intersects the sensitivity curves.
Far more likely than a few isolated wavelengths of light is a group of many different wavelengths that may be reflecting off of an object or coming from a light source. In the case of a broad spectrum like this, we find the intersections of all of the different wavelengths and consider an average value that represents them (see figure 6.5). In this fashion, every imaginable combination of light can be boiled down to a vote from each of the classes of photoreceptors and transmitted as a three-digit number to the brain. The three digits are what make color space a three-dimensional place with so many possible color experiences.
Figure 6.5 Even a very complex spectrum is translated by the photoreceptors as a single 3-digit number.
Although the wavelength characteristics of light are absolute, the detection of light and translation of color are far more subjective. Every person’s visual system has slightly different peak sensitivities and different ranges of detection. There are individuals who detect certain wavelengths of light that other people do not. They, therefore, have color experiences that some people may never have.
This model of color vision leads to the understanding that the sensation of
“color” is merely the brains translation of the retina’s detection of different quantities of different wavelengths of light. This has important ramifications in that we can artificially create any color experience we want through an engineered combination of many different wavelengths of light.
Scotopic Vision from our Rods
If we can visualize the interaction of our cones, understanding how rods work is very simple. In the case of our rods, there is only one class, one photopigment, and, therefore, only one vote. The information that is transmitted to the brain is a single number. Because of this, low-level “Scotopic” vision is a monochromatic experience. The brain is being furnished with only enough information to make a value judgment: simply dark or light.