White Balance for Colour Optimisation
August 21, 2008
White Balance, also known as Colour Correction basically refers to an application that prompts a digital camera to conceive white subjects at their whitish best and not as tints of various colours. This aspect can also be observed in the human-nature correlation, where human eyes and brain tend to ignore or fail to notice the variation between different colourations of light that occur in different places as well as times. For example, human beings know that a paper sheet is white and hence see it as white. This phenomenon can be called, 'intuitive white balance of the nature. However, a digital camera being not as intuitive as a human being, lacks this reasoning capability and hence conceives the world as it is actually.
When observed carefully, one can find that early morning colours tend to be a bit on the bluish side on sunny days. Middays possess balanced colours as evening or late afternoon colours usually tends to be a bit reddish in nature. The fact behind these colour variations refers to the distance travelled by the sun rays through the atmosphere before hitting the earth's crust. The longer distance the sun rays travel more scattering takes place. Until recent times where films ruled the photography sphere, film manufacturers designed different films fitting different light conditions such as outdoor, indoor, morning light, evening light, etc, in which a correction coluld not be performed unless a filter was posted in front of the lens of the camera. However, digital cameras emerged with the scope of a radical change in this field.
White balancing in a digital camera is explained primarily by the separating of the primary colours (red, green and blue) from the inbound sun rays. Consequently, the separated primary colours are changed into electrical signals by the digital camera's imager and are processed separately. Further, these colours are matrixed together complying with certain fixed standards to obtain composite video signals. These signals are subjected to colour addition in the processing stage itself by the digital camera. The end results are explicit images of real colours.
A good lot of photographers tend to change the white balance of those images captured by them, at a later stage using the image-editor application available in most advanced digital cameras. This process however, cannot be considered ideal, for the camera itself processes the image prior to saving it as a JPEG compression file. In this process the camera applies the appropriate white balance too, to the image. When a second edition is performed by the photographer, a considerable quality loss is inflicted on the image. This refers to a couple of smart steps for the photographer to optimise the colour details of his/her images. The first one is obviously setting the appropriate white balance for the scene in the camera. The other step is the smart way of capturing images in RAW mode to edit it according to the photographer's tastes later using the camera's edit tool or a computer.
Another mistake that is made usually by a beginner, is setting the white balance of the camera in automatic mode trusting blindly the camera's intuitions to adapt according to the available light. This can result in spoiling the images, for the camera would try to normalise the colours in the scene after subjecting them for analysis, which often comes a cropper for the lack of intuition in its part to differentiate between the intrinsic colours in the subject and the colour of the available light. Here, switching to the appropriate white balance presets would be a sensible act for they can render realistic colours that are warmer while more often than not, the auto mode fails in conceiving the perfect correction for shady conditions. A clever photographer exploits the white balance presets of the digital camera by virtually spoofing it. For example, the white balance presets is set to cloudy mode for capturing a colour-rich sunset. Here, the camera, being fooled by the photographer, renders high quantity of warmth to the image that in its turn exhibits its red details to the maximum consequently subduing its blue details.
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