Project 7: altering colours with levels

For the first part of this project I had to use Levels to change a colour precisely, opening the OCA colour chart I then used the middle sliders to change the values of the Red Channel then the Blue Channel to match the value of the Green. This was quite tricky to do as I couldn't find a way to have both the Levels information panel and the colour picker palette info panel open at the same time. Adjusting the slider bit by bit I eventually got as close as I could. The first adjustment made the orange square green with the second adjustment achieving the as close as possible neutral grey.




OCA Colour Chart orange square altered to neutral grey in 2 steps





Values	Orange Square	Green Square	Grey Square
H	30°	60°	240°
S	69%	53%	1%
B	91%	59%	59%
R	231	150	150
G	150	150	150
B	71	71	151

Obviously this task has shown that it is possibly to adjust colours to neutral and remove a slight colour cast. Hopefully any photograph taken would not have a cast as great that you would cause such an exaggerated shift as above. As demonstrated when you alter for the neutral all other colours will also shift.

The second part of this project entailed choosing an image which contained a colour that I thought should be neutral. I chose an image of a bus shelter taken near Brick Lane in London.

Brick Lane

I took a sample of the bus shelter and was pleased to see the readings were almost spot on the RGB values being 166,166,162!




Neutral sample before adjusting


I then used Levels adjustment layers to increase the Blue channel. It took four very small increments to reach the correct Blue value of 166 and the saturation to read 1%. A fiddly task but worth it learning/understanding and refining to rescue any other image that otherwise might have been discarded.

Neutral sample after adjustment

This may not have been a brilliant choice of image in some respects as the adjustment was minor, with no strong cast I did not have to overly worry about the other colours shifting too far, having said that if there is a strong cast to an image the colours would need to shift that far to register correctly. It has shown that my judgment of white balance on the day of shooting was good and that my judgement of what should be a neutral colour has improved since DPP.