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Also known as white balance, this is a camera setting that allows you to compensate for the colour of the light that is illuminating your scene.

We don't really see that different light sources have different colours because our normal vision compensates for that perfectly. We may be aware that candle light is a bit yellow or that, seen from outside, the lights inside a house can sometimes look a little orange but that's about the limit of our awareness.

One thing we are seldom aware of is that when we sit in a room lit by artificial light and look through a window, the outside world is relatively blue, but that's what a camera sees. In order to reproduce colours correctly, a camera needs to be "balanced" for the colour of the lighting.

So, what we find amongst the options for white or colour balance are different lighting conditions. Typically, they will include "sunny", "cloudy", "tungsten" (meaning ordinary indoor lighting) and maybe "fluorescent" or "flash". One problem can be that these are often depicted as small picture icons and it can be difficult to tell exactly what type of light source each one is meant to represent. The only answer to this is to look carefully at your manual and try to match up the symbols with the light sources.

 

These are likely to be the only options available on an inexpensive compact camera, along with an "auto" setting. As with ISO numbers, this is likely to be the default setting and the best place to leave it for beginners. The auto setting tries to do what we do and automatically adjust the colour balance for you. Most of the time, this will work perfectly well. But, if you take a picture and the colours look wrong, this is where you go to fix it.

 

Slr and Dslr camera owners will have further options under the heading of colour balance. One is a list of numbers. These are numbers on a scale called degrees Kelvin. It is in degrees because it is a scale of temperatures. It is exactly the same as the centigrade scale except it starts at absolute zero instead of the freezing point of water. This doesn't really matter because all the numbers we use are in the thousands.

 

The only real difficulty here is that we usually refer to a wrong colour balance as either too "warm", meaning too red/yellow or too "cold", meaning the picture has a blue cast. Unfortunately. it's low colour temperatures that give a warm cast and high ones have a blue tone. If you can get your head around that one you're well on the way to understanding what these numbers are all about.

 

Most lighting, both natural and artificial, fall onto this temperature scale somewhere. The settings you have for specific light sources are actually preset colour temperatures. So, setting the colour temperature with these numbers is an alternative to using the light source icons. The difference is that it allows you to use settings between your presets.

 

Your manual should tell you what the manufacturer has set these presets at, but typically they might include candlelight at around 2500 degrees Kelvin (2500K), tungsten (normal room lights) at 3200K, sunny (5600K) and cloudy (6500K). It's not important what the numbers actually are, all you need to remember is that a lower number means a warmer colour and a higher number means a colder colour.

 

In practice

It's only once you have taken a photograph and found that the colours are wrong that you need to bother about colour balance. If the picture looks too red/yellow (too warm) that means your camera's setting is too high. Use a lower colour temperature and try again. Similarly, if the image looks too blue (cold) change to a higher number. It is not unusual to be working in a situation with mixed lighting. For example, indoor lights with some light coming in through a window.

 

In this case, the actual setting you need will probably be somewhere between that of sunny and tungsten. Try starting around the 4000K mark and use the above rules, go up if it's too cold, down if it's too warm in tone. After a few goes, you should be there. But wouldn't it be great if your camera could take a reading of the colour temperature and just give you the correct setting without all this trial and error.

 

 

It would, and if your camera has a manual colour balance option, it can. This is actually what white balance means. The camera reads the colour temperature and balances the camera for it. The reason why the auto setting sometimes fails is because the camera can sometimes be fooled by the actual colours in the scene. If there is something red filling most of the frame then overall the image will look red. The camera might think that this is because the light source is red and adjust accordingly, making all the colours wrong.

 

Grey card

So, what we really need for a colour temperature reading is a reference point, which you have to supply yourself. Most commonly, this is a white piece of paper, hence the name white balance. You can also use grey, but it must be absolutely neutral. Grey cards, made for this purpose are available from photographic outlets.

 

You place the paper in your scene, so it gets lit the same way, fill the frame with it and take a reading. There will be a description of exactly how to do this on your camera in its manual. In some cameras, you simply press a button to store the colour balance reading, with others, you take a picture of the paper and use that image as a white balance reference.

 

Because the colour temperature of the real world is hardly ever exactly at any of your preset values, taking a white balance reading is the only way to guarantee a completely neutral colour balance so all the colours in your photograph will look natural.

 

But there are exceptions, Not all light sources fit neatly onto the colour temperature scale. Fluorescent lights can have a distinctly pink or even green hue. Most cameras have a fluorescent preset for this very reason. However, sometimes, even a manual white balance cannot cope with this type of light. In this case, all you can do is either turn of the offending light or try to adjust the colours later in editing.

 

Alternatively, all Dslrs and many slr cameras allow you to save pictures in a "raw" format. This is different from the other image formats in that it requires specialised software to even see the picture. But the software (usually) can do a great deal more than just view pictures. It actually allows you to adjust camera settings after you have taken the picture.

 

In a digital camera, the information from the image sensor has to be "processed" by your camera's computer before being converted into a normal image format, like jpeg, and stored on the card. It is during this processing stage that the settings of your camera are applied to the image. A "raw" image file represents your picture before it gets processed so you can change your camera settings at a later date. The raw processing software will have some controls familiar to you from your camera, including colour balance.

 

What this means in practice is that, if you "shoot raw", you can ignore all of the above, at least while you are taking the shot. Once the image is downloaded into your computer, you use the raw processing software to adjust the colour balance just as you would in the camera. Even if you want to do a white balance, all you need is an image with your white paper (or anything else that is white or neutral grey) somewhere in it. You don't need to fill the frame or press different buttons, just take the picture.

 

Even if you don't use the raw format, it is still possible to adjust the colour with a good photo editing program. There is, however, a danger of losing a little quality in doing this, especially if you have to make large adjustments. Using the raw format eliminates this problem completely.

 

One last point, some lights behave badly. At least they don't have what it takes to reproduce colours properly, no matter what you do. The most common example is street lighting, especially yellow (sodium) lights. If you can't get the colour right on a picture taken under sodium lighting, don't worry. It's not you, it's not the camera, it's the light.

Colour balance