Guide: White Balancing in Photography

The Basics

White balancing allows you to even out the colours in your photographs so that they are neither 'too warm' nor 'too cold'.

The majority of digital cameras can detect the colour of the light source in your photo by themselves and provide the right white balance, especially outside.  However, they can often get it wrong indoors where the light is very different to natural sunlight.

Setting it manually is generally rather simple, and doesn't require too much technical knowledge: you can simply adjust the settings on the screen until they match what you'd like to see.  On some cameras, you can also use an object that you know to be neutral, like a white sheet of paper, and use that to customise the white balancing.  That takes a little longer, but guarantees a good result. 

Colour Temperature

What is white?  It might seem like a childish question, but it's a very important one for people who work with photo and video.  An object that appears white reflects all of the light that falls on it, but that light isn't necessarily 'white' itself: think of a red sunset, for instance.


As a reference for natural light, we use the sun on a clear day; when there are clouds, sunlight has a blue tinge, while artificial light is generally red or yellow.  On the right is a special lamp we use when taking photos for our Product Face-Off.

To classify different lights, we refer to a scale of colour temperatures, measured in Kelvins.  Normally, sunlight is around 5 500 K, but that quickly climbs to around 6 500 K on a cloudy day or in the shade; a candle is under 2000 K.  Confusingly, a lower colour temperature produces a 'warm' light (yellow or red) while a higher temperature produces a 'cool' light (blue).


The sensor in a camera reproduces these conditions faithfully, and so if you photograph a white object under a red light, the object will look red in your photo.

Your eyes, on the other hand, can compensate for different light sources.  Without ever realising it, we constantly compare the colour of the light and the colour of the object: for us, the panda's head remains white under any lighting.  It's only when light is particularly different to what our eyes are used to that we notice its colour--like coloured lights used in a concert or at the theatre, for instance.

That means that we have to adapt the camera to the current light conditions to produce a 'natural result', which will, in fact, be an artificial retouching of what the camera sees to match the corrections that we apply automatically ourselves.

White balancing

The setting that allows you to adjust the camera based on the temperature of the light source is called 'white balancing'.  When we still used film cameras, it depended heavily on the film stock you were using.  Most were designed for taking photos in sunlight and produced very different results under other conditions.

With digital cameras, though, it's a lot easier to set the white balancing, and most cameras can do it themselves.  Some of them are excellent at it, but light sources that are different from the standard of natural sunlight continue to cause problems for a lot of models.


The examples above show the same same scene illuminated by a very warm light source (the special lamp that we talked about earlier), as it was captured by three different cameras.  The most faithful representation is the one on the right: the teddy bear and the map both look a little red because of the warm light source.  At the other extreme, the camera on the left has over-corrected, and areas that should be white are actually a little blue, while warm areas (the red on the car and the yellow flower) are too dark.

It's important to remember that neither camera gets it wrong: one depicts reality honestly, the other tries to improve on it.  While some photographers can't stand warm tones dominating their photos, there are just as many who prefer to maintain some of the tonality that make up part of the atmosphere of the scene they're photographing.  It's often a question of taste.

Seen this way, it's the camera in the middle that has opted for a compromise.  It has done a lot of correction, but some traces of the warm light remain.  The teddy isn't entirely grey for example, but includes some light browns.  Looking at a photo like this, it's immediately obvious that it was taken indoors under a warm light, but the warm tones aren't strong enough to be overpowering.  It's a solution that will satisfy most people..

Adjusting white balance

It would have been possible to take the same photo with the cameras on the left and on the right--but first you have to deactivate the automatic white balancing so you can choose the correct settings yourself. 

With most manufacturers, you can't manually adjust the white balance in intelligent automatic mode, so you need to switch to 'program' or P mode.


The next step is finding the setting you actually need.  There isn't a standard pictogram to represent white balancing, and although the letters WB are often used in menus, not all manufacturers do this.

The options on offer are nearly always the same: you'll find a menu which shows a sun, a cloud and a light bulb.  Those manufacturers that have a quick menu (Func. for Canon, Q.Menu for Panasonic, F for Fuji …) include it there, but others relegate it to the main menu..


it's usually the preview that will be the most use.  The majority of cameras display what the photo will look like as you move from one setting to another.

Note that the SLR (bottom right), has a dedicated WB button to give direct access to this setting, and gives a preview based on the last photograph taken because it doesn't have a Live View mode.

You can then choose the setting that goes with the lighting conditions at the time, but you'll need to change it every time your light source changes.  It's a good idea to put white balancing back to automatic before turning your camera off to avoid any nasty surprises when you use it again a few days later with entirely the wrong white balance.

Limitations

Unfortunately, these general rules for white balance can't do much if the lighting situation is very complex, such as a portrait subject standing next to a window and lit from one side by sunlight and from the other by artificial light.  In such situations, there's only one solution: retouching the photo afterwards on a computer, preferably starting with a RAW file.

That hasn't stopped Ricoh experimenting with systems on its latest digital cameras that analyze the scene in the hope of detecting situations like the one we described and applying different white balances on different parts of the photo.  However, this new 'multizone white balancing' has yet to prove its worth.