Clive R. Haynes FRPS

To continue our exploration of 'methods of adjustment' within Photoshop we'll look at 'Brightness & Contrast' next.
Brightness & Contrast
Here's the same image again, this time adjusted simply by using the two 'Brightness & Contrast' sliders.
However, this is still not very much by way of 'control' and it's not particularly flexible or subtle.


Above: Brightness & Contrast adjusted
Above: The Brightness & Contrast dialogue box

'Levels' offer a greater degree of control and sophistication.

We now have five points of control (three 'input' and two 'output'), with the added sophistication that we can set both the 'black point' and the 'white point' and have control over the mid-grey setting

Above: The opening state of the 'Levels' dialogue box for our demonstration image.
Note the flat lines at each end of the histogram. These represent the darkest tones (lh) and the lightest tones (rh) within the image. The darkest tone falls short of absolute black and the lightest tone fall short of absolute white.
The triangular sliders can be moved to set the 'black point' and the 'white point'. Doing this will improve image contrast.
The mid-point for the image 'exposure' can be set with the centre triangular slider without adversely affecting the black or white points of the image.
'Levels' therefore introduce a more subtle form of control.
(For more information about using 'Levels' click on the link below)

Above: Levels adjustment
Above: The Levels dialogue box - after setting
This is an improvement over the 'Brightness & Contrast' setting
Next, we move on to 'Curves' - click the link to the 'Next Page' below

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