The Fourth Element.- White Balance.

White Balance is an aspect of photography that many digital camera owners don’t understand or use but it’s something well worth learning about as it can have a real impact upon the shots you take.

 I say it as fourth element because the first 3 are Aperture, Shutter Speed and ISO. These 3 are already being discussed in my earlier blog.

White Balance is considered as one of the most important settings of a digital camera. White Balance doesnt really affect you exposure, just the appearance of colour in the image.

Different light sources cast their own colours which cannot usually be noticed with the naked eye. White Balance is essentially the camera compensating for the colour cast of the light in order to reproduce the correct colour. In short the reason we adjust white balance is to get the colours in your images as accurate as possible.

You might have noticed when examining shots after taking them that at times images can come out with an orange, blue, yellow etc look to them despite the fact that to the naked eye the scene looked quite normal. The reason for this is that images different sources of light have a different ‘colour’ (or temperature) to them. A digital camera can measure the colour in the red, green, and blue light of the spectrum, as reflected to its sensors. In a photo taken under the midday sun there is the whole spectrum of light (which makes up “white” sunlight). Under these conditions, the colours in an image appear nearest to the “true” colours. An image taken under tungsten bulb (a normal household incandescent bulb) without adjusting the digital camera for white balance produces the dull orange shade as it spreads the biased light. Similarly, an image taken under the fluorescent lighting produces a brighter bluish cast.

We don’t generally notice this difference in temperature because our eyes adjust automatically for it. So unless the temperature of the light is very extreme a white sheet of paper will generally look white to us. However a digital camera doesn’t have the smarts to make these adjustments automatically and sometimes will need us to tell it how to treat different light. So for cooler (blue or green) light you’ll tell the camera to warm things up and in warm light you’ll tell it to cool down.

To understand the concept of White Balance, you need to first understand the concept of colour temperature. Colour temperature is a characteristic of visible light. It provides a method of describing these characteristics and is measured in Kelvin (K). A light having higher colour temperature will have more blue light or larger Kelvin value as compared to lower light, which has a smaller Kelvin value. The following table shows the colour temperature of various sources of light.

Colour Temperature	Light Source
1000-2000 K	Candlelight
2500-3500 K	Tungsten Bulb (household variety)
3000-4000 K	Sunrise/Sunset (clear sky)
4000-5000 K	Fluorescent Lamps
5000-5500 K	Electronic Flash
5500-6500 K	Daylight with Clear Sky (sun overhead)
6500-8000 K	Moderately Overcast Sky
8000-10000 K	Shade or Heavily Overcast Sky

Here are some of the basic White Balance settings you’ll find on cameras:

Auto – this is where the camera makes a best guess on a shot by shot basis. The Auto setting helps in adjusting the white balance automatically according to the different lighting conditions. You’ll find it works in many situations but it’s worth venturing out of it for trickier lighting.

Tungsten – This mode is used for light under a little bulb like tungsten, and it is often used while shooting indoors. The tungsten setting of the digital camera cools down the color temperature in photos.

Fluorescent – This mode is used for getting brighter and warmer shots while compensating for cool shade of fluorescent light.

Daylight/Sunny – This mode is for the normal day light setting, while shooting outdoors.

Cloudy – This mode is ideal for while shooting on a cloudy day. this setting generally warms things up a touch more than ‘daylight’ mode. and allows you to capture better shots.

Flash – the flash of a camera can be quite a cool light so in Flash WB mode you’ll find it warms up your shots. The flash mode is required when there is inadequate lighting available. This mode helps pick the right White Balance under low light conditions.

Shade – the light in shade is generally cooler (bluer) than shooting in direct sunlight so this mode will warm things up a little.

Manual White Balance.

In most cases you can get a pretty accurate result using the above preset white balance modes – but some digital cameras (most DSLRs and higher end point and shoots) allow for manual white balance adjustments also.

The way this is used varies a little between models but in essence what you do is to tell your camera what white looks like in a shot so that it has something as a reference point for deciding how other colours should look. You can do this by buying yourself a grey card which is specifically designed for this task – or you can find some other appropriately coloured object around you to do the job.

To manually set the white balance in your image, first set your WB to custom then point your camera at the grey card and make sure all the lights you’re using fall on it, and hit the shutter button for your test shot. (frame should cover most of the card) The camera sees the difference between the result and the neutral hue and determines the balance from that.

Shooting Raw.

The alternative is to shoot raw files rather than JPEGs. With JPEGs, the camera will discard ‘unwanted’ colour data according to your White Balance setting. You can’t get it back, even if you realise you’ve made a mistake.

Raw files, however, retain all the colour data captured by the sensor. The camera will embed your White Balance setting in the file as a default, but it’s purely advisory, you can choose a different setting on your computer later.

It’s still useful to set the White Balance on the camera. It will save time later if your RAW files have the best White Balance setting applied, and by choosing a consistent White Balance during your shoot, you ensure that the colour rendition will be consistent across all your shots.

       Original Photograph

After Correcting WB