Quote - There is only ONE main light source in a room.

I'm sure you mean in daytime. But still,

As an architect, I would have to refute this.

Interior scenes have commonly a LOT of light sources, and part of the magic of well designed interior spaces is having the user focus his attention depending on, among other things, lighting.

"Architecture is the masterly, correct, and magnificent play of masses brought together in light." Le Corbusier

What is also true is that it is very common to have most of interior scenes in shadow, so you need lots of lights to illuminate an interior, as walls and other elements occlude the light coming from outside. This is not usually perceptible as we unconsciously brighten scenes. We are hard-coded to perceive this way. But just walk outside in the sun and look towards he interior of an unlit building through a window. Quite dark. And if you take a picture the effect is even more pronounced.

In other words, even when we have a much more dynamic range of possible colours and luminosity perception in our eyes, we also have automatic gamma correction built in.

A gamma correction world does mean we have to take more things into account. But it also means that getting consistent, predictable results is much easier and faster in the medium and short term.

An architect's translation of Bagginsbill's gamma correction explanation :)

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