Light is the basis of photography. Light can be hard or soft, warm or cold, mottled, diffused, or any number of things really. Light also has a temperature. Neutral sunlight should be around 5500K. This is what light from the flash is also calibrated towards, but how appealing is direct and neutral sunlight? It doesn’t make us feel anything. Warmer light, such as that from the sunrise or sunset is infinitely more appealing. Tungsten lighting, frequently found indoors in most of our light sockets, has a temperature of 2850K. In digital photography, we are able to set the white balance of the camera to match the color of the light as our eye might do, making whites stay white, and it can get ugly if we use the wrong setting. Last year, I saw the result of an entire photo session captured with the camera set to tungsten while shooting under daylight. Every photo was bright blue. This happens because tungsten light is more yellow and the camera would cool off the light per se to make it appear white. Since daylight is already white, it cooled it off into the realm of blue.
It becomes a challenge then when using multiple light sources. Ideally, the lights could be color balanced by swapping bulbs and adjusting the white balance in the camera. Sometimes we’re not so lucky and we’re left with a color cast in the final image. In the top image, both sunlight and tungsten light were supplying light. The sunlight was arriving diffused through the window and the tungsten from overhead. Without having daylight balanced bulbs, I was left with a mostly yellow photo that I tried to salvage in Lightroom. Yet another reason to shoot in RAW format.