If you use a point-and-shoot type camera, or a smartphone, or any camera that delivers a JPEG, rather than a RAW file, you have to set the white balance before you press the shutter button.

White balance is a measure of what the light you are using for your shot is doing, temperature-wise. And it can be anywhere along a very long scale, from about 2000 Kelvin to about 15000 Kelvin.

What we perceive as red and yellow light lie near the bottom end of the scale. For example, the light from a tungsten bulb is yellow (though our brain corrects it to much closer to white), at around 2850-3200K. The surface of the sun is about 5600K, and we are used to interpreting that as white light. However, in deep shade, or moonlight, or a snowfield, the light can be 10000K.

If you set your camera's white balance to 'Auto' you give it the hard task of guessing what the temperature is along the scale, when it doesn't have the foggiest. So, the camera has to use cues from the scene to guess what temperature will render whites/neutral greys/blacks accurately. If the cues it gets mislead it, you get the wrong colours in your photo. Cameras tend to concentrate on the biggest contribution of lighter tones and hues as a way of guessing what is white. That works quite well on a lot of occasions, but it is very far from fool-proof.

Here is a good example...

I took a photo of a giant orange buoy on Loch Lomond. The orange so dominated the scene that the camera tried to balance the white based on the buoy. If I had shot a JPEG on Auto white balance, it would have given me this...


It reckoned the temperature of the light was 2850K - the same as a tungsten bulb. As I shoot RAW files, I only needed to set my own white balance after taking the shot. Changing it to the preset for cloudy (6500K) corrected the error nicely...


The reason I am pointing this out is because I see a lot of photos posted to this forum and elsewhere on the internet that have clearly been taken by cameras set to Auto white balance... and the camera has got it wrong! Most of them err on the side of being too 'cold', so skin tones are pink, and the overall scene has a blue colour-cast and looks cold and uninviting.

The answer is simple - don't trust Auto white balance. The vast majority of cameras have white balance options on them. If you are shooting in normal outdoor daylight, try setting white balance to 'Daylight' (~5600K) - it will usually give good results. If you want it warmer still, try the 'Cloudy' setting (~6500K).

But don't take my word for it...



Col