"Nick" wrote in message
Sometimes when I do levels on a pic with whites, I start to get coloured artificats appearing. Why does this happen and how can I avoid it?
There are several causes for this. First, the RGB master curve should probably not be used most of the time, because it introduces a hue shift, as well as a change in saturation.
Try this: convert to Lab mode, and try doing a similar adjustment to the Lightness channel. If the problem goes away, you have your answer.
Another common problem is color noise in the shadows – making the shadows brighter will create a colored grain effect that may be what you are seeing.
Post a copy of the image to imageshack.com, or flickr.com, and some of us will take a look at it.
—
Mike Russell
www.curvemeister.com/forum/
