If your
image has an unwanted color cast to it, you can adjust colors under Adjust:
Levels (previous demo) and go into each of
the individual color histograms, changing the sliders for that color until
you get your desired effect (look under Channel RGB, click on arrows to
the right). Or you can useAdjust: Color Balance also under the Image Menu,
again adjusting the sliders for that color until you get your desired effect.
For this adjustment also, always set Preview box OFF [A]; this way your
entire screen shows the effect of the adjustment you are making and by clicking
on the upper bar of the Color Balance box [B] you can contrast this adjustment
with what the original image looked like. If the Preview button is checked
this feature won't work.
Using either method, adjusting colors can get tricky as the colors work blended with each other and are not independent. The best thing is to get the best original image with the most accurate color. I know this isn't always possible and you will end up having to do something with color eventually. (However, you don't need to make color adjustments if all you want are grayscale images.)