Effects of Temperature of Light
These two photographs reveal the difference between three different Kelvin temperatures. The image on the left was taken using daylight balanced film. The room is lighted with a 60 watt household bulb at dusk. The white walls have gone orange and the outside light is a deep blue. (Daylight film at 5500°K; tungsten light at about 2700°K; dusk well into 8,000°K.)
The second shot was adjusted using the equivalent of an 80C filter. Notice the dramatic "cooling-off" of the room. Not quite perfectly balanced, but much improved. And look at the color through the window. Yes, the world turns that blue at dusk! In fact, the French have a special name for that time of day, "Heure bleue," or "The Blue Hour."
Photograph taken without filter
Photograph taken with filter