Have you ever noticed that when you take pictures in the daylight, it will look different to when you take pictures inside a room or in the shade? You also might have also noticed that some pictures tend to be a bit bluer than others. The answer is found in the colour temperature of the image, which is commonly referred to as white balance.
In short, different light sources like the sun, fluorescent bulbs or tungsten lights have different colour temperatures that determine how much warmth (red) or coolness (blue) is present in an image.
Setting the correct white balance is a key aspect of photography, as it will affect the final shot.
The correlated colour temperature of candlelight, as an example, is between 1000-2000 K, tungsten light bulbs which is most commonly used in households, is 2500-3500 K, and a sunrise or sunset under a clear sky is 3000-4000 K. At the high end of the scale, shade or heavily overcast sky has a colour temperature of 9000-10000 K.
The human eye is excellent at differentiating what is white under different light sources, but by nature digital cameras can struggle to capture the same scene perfectly. Almost all digital cameras will have an auto white balance (AWB) setting, but even then they might need some help from time to time.
To get the most accurate representation of what a scene looks like, you would have to set the camera’s white balance to one of the pre-defined options, which consists of a list of light sources. The camera will then automatically adjust the scene’s temperature to the one selected.
It should give you a pretty good reproduction, but if that doesn’t work, it’s over to manual control – which can get a bit tricky at the best of times.
In manual, you will need to set a benchmark so that you can tell the camera what white looks like in a scene. It seems a bit silly, but the results will be well worth the effort. The easiest way to calibrate the white balance manually, is to get a piece of white cardboard. Photograph the cardboard and check out the results, and from there you will be able to establish just how much you need to adjust the white balance.
You also get what is called a ColorChecker, which is essentially a piece of cardboard with 36 different colours on it arranged in a 9×4 grid. This is an excellent way to calibrate for almost any colour, but it won’t be practical for amateur photographers to walk around with a ColorChecker before every shot in different lighting conditions. In filming, the correct colour balance is gained by placing colour correction filters on the camera lens or over the studio lights.
As with anything in the photography world, colour can be used to change the tone and emotion of an image.
Images taken with a warmer white balance tend to resemble photographs taken many years ago, creating a retro or vintage feeling. Some digital cameras have an effect setting called Vivid, which also tinkers with the white balance, usually making the image warmer.