Light sources
If you are new to photography, then color temperature may not be the first thing you worry about. There are many other dimensions of photography that demands you attention, ranging from selecting the right camera and lens, to composition and exposure. However, when you have found your feet and start getting the results you want, then white balance and the color temperature of light may start to be one of the more advanced subjects that you want to dive into.
Every light source has a certain color temperature. It is measured in Kelvin, and for reasons beyond me, it is typically on a scale between 2000 and 10000, and to signal it is a value on the Kelvin scale, a “K” is added after the number. So for example candlelight is 2000K whereas an overcast sky is around 6000K. So low values equals more red, high values more blue and in between is white.
You are fast!
No, I don’t write that headline to charm you, but it is a fact that your brain adapts to new light sources with astonishing speed and probably without you noticing. So if you walk from noon daylight (5200K) into a tungsten lit living room (2500K), then you’ll adapt to the new temperature of the light super fast and probably without noticing. And colors will look like they always do, and white will look white, simply because you adapt fast to a new light source. It is really smart design!
Your camera is not so smart
You camera is not so smart. In order for it to record the light in a way where the images that comes out of it look natural (e.g. white looks white), then the camera needs to know the temperature of the light. If it doesn’t, then I can assure you the colors will be strange – white will be yellow and blue will be purple, etc. So you need to tell the camera what color temperature you are shooting at.
Auto white balance
Luckily, most modern cameras has an option named auto white balance where the camera itself reads the light and figures out the color temperature of the ambient light. It works really well in most cases. You can try to play with a manual setting of the white balance, just to get a feel for what happens if the white balance is off and what options this gives you for giving your images a distinct look. If you have ever seen images by Bryan F. Petersson, you can find some amazing images where he gives the night sky a distinct purple look using manual setting of the white balance.