I studied the physics of light in college. At the time of the dinosaurs the atmosphere was pink because of the humidity level was so high. Today the sky is blue. Light can be reflected, refracted and filtered. In paint when you add color you are actually subtracting the ability of the paint to reflect. When you filter light this is called the additive color theory. When you take a photograph you are recording the light that is reflected off of an object. The light this is absorbed can not be photographed. My camera has bounce flash so I bounce the light off of the wall or ceiling to give a more softer and defused light for the person I am photographing. I remember once in Hong Kong they were filming a boy and a girl on the beach. There was a camera man and another person with a reflector to bounce the sun light off of the actors and onto the camera. It was overcast that day so the light they were using was filtered by the clouds and a lesser quality light if there had been no clouds that day.