How is color saturation (rg) possible?

[autumncrown]

My understanding of how a flashlight works is

1. visible light shoots out of the flashlight.
2. the light hits an object
3. some of the light is absorbed by the object and some bounces back
4. The light that bounces back is what gives the object color for an observer

Based on this model, I would think average color saturation would be entirely a function of how much light you are shooting at your objects. What I do not understand is how a light source can have more color saturation than another, if color saturation is determined by how much of a given wavelength bounces off an object. That is just brightness - and because rg is an average across all colors, I don’t understand how it can vary independently of brightness.

If color saturation is not determined by how much light of a given wavelength bounces off of an object, then what is it?

[autumncrown]

To answer my own question, if I understand correctly LEDs can produce more saturated colors than sunlight by having more energy at wavelengths that correspond to bright colors (high chroma), as opposed to wavelengths that correspond to dull colors (low chroma).

From this website:

What's the difference between CRI, CQS, & IES TM-30 and why is it important?

The definition of the word ‘gamut’ is “the complete range or scope of something.” The Gamut Index, in lighting, is used to measure the increase or decrease in Chroma of a light source. Chroma is the quality of the color’s purity, intensity, or saturation. For instance, the color of a red fire engine is a high-Chroma red and a neutral gray is a low-Chroma color. An Rg score that is around 100 means that the light source can produce colors with a similar level of saturation as the sun at daylight (approx. 5600K/6500K). When looking at LEDs, to get an acceptable color quality, the score should be between 80 and 120; higher scores represent higher levels of saturation (the intensity of color). When the score is above 100, the color will be more intense than it’s natural color in the sunlight.

[BlueSwordM]

Basically, it’s dynamic range.

A 5000k light has more dynamic range than a 3000k light.

[twisted_raven]

LEDs can oversaturate in the same way that a TV can oversaturate colors in its reproduciton…by pushing the chroma values of the reference colors far beyond what they should be. Remember that CRI and all of its parameters are comparing a particular light output vs a reference theoretical black body radiant of the same color temperature. If the theoretical illumination only pushes the chroma of particular hues so far within a particular color space, and the LED pushes them even further out, then it is over saturating.