I understand that ambient light is light that occurs a result of light from a given source refecting off an infinite number of points in a scene, thereby illuminating all objects in the scene uniformly and explains why areas not directly illuminated by a light source in a scene aren't pitch black.
So I guess ambient light gives everything in the scene the same basic "brightness". But how does one determine this value? I presume the ambient light is proportional to the primary light source intensity (a floodlight in a bedroom will surely produce more ambient light than a lit match in the same room) and inversely proportional to the scene size (a lamp in a closet surely produces more ambient light than a lamp in a hall). Is there a formula that gives ambient light "brightness" as a function of scene volume, light source intensity, and any other variables please?
Please excuse my naivety, as I'm a noob to computer graphics, and only a hobbyist at that.