Registered: September 2007 Location: Near Cheltenham Posts: 149
Sat December 29, 2007 11:04pm
I assume that the big problem with this photo is the colour cast.
The colour cast is not caused by too much of one colour but by an absence of its complementary colour in the lighting.
One trick that sometimes works is to add the complementary colour.
Using the colour picker to measure the colour on the canine tooth on the left I got something like 255, 181, 166 the complementary colour is 0, 74, 89. (Just subtract each colour value from 255.)
Now we want to put this colour back into the picture.
1. Make a copy of the image in a new layer.
2. Open a Gradient Map adjustment layer above this copy.
3. Group the Gradient Map adjustment layer with the copy. Either use Layer > Group With Previous or just do a Control + G while the Gradient Map Adjustment Layer is selected.
4. Open the gradient map and go into the gradient editor.
5. Set the left hand lower slider to black and the right hand one to the colour 0, 47 , 89.
At this stage we have a cyan picture which we need to add to the original.
The blending mode of the copy needs to be changed to Linear Dodge. Linear Dodge simply adds the colour values of two images together.
This removes most of the colour cast but a little tweaking with the right hand colour values can remove a bit more of the colour cast. I tried increasing the brightness a little and moving the slider a bit to the left but the final adjustment is a matter of choice. The overexposed area on the right has turned somewhat cyan but this can be recovered by blending in the original in this area.
I must say that after that process it looks as though the dog is the one needing treatment.
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