Friday, 12 October 2012

Back to the Basics Part II: White Balance

Back to the Basics Part II: White Balance

How it works

White balance is a setting contained within your photographs that determines the adjustment of colours within a photograph needed to match the colour of light shown by the light source. The object of this matching process is so that white objects appear white under varying lighting conditions. While most light sources appear white to the naked eye, the truth is there is a wide range of colours cast by traditional light sources. For example, light from the sun is a very cold blue and a traditional tungsten light bulb gives a very warm orange to red colour. The imaging sensor in modern digital cameras reproduce the colours cast by these lights exactly, and without processing and white balancing, the colours in the photograph would seem to change from light source to light source. Normally auto white-balance would correct any issues, however it is not perfect and for greater control and artistic leverage, the manual function for white balance can be used to derive very different results. These differences are illustrated in the photos below.


 

In this photo you can see that it has a blue colour cast over the photograph, while the background is a orange/ red. this is because there is three different light sources in the photograph, each with its own band of light.


In this corrected version, you can see we've adjusted for the blue in the photograph, however the background is still very orange due to it being a separate colour cast to balance for. It is recommended that you try and minimize the number of differing light sources as it becomes a nightmare to edit more than one at a time.

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