> > I think the difficulty is how to decide where the mid-grey point is. > > Once decided upon then action is easy. > > I thought the tutorial might have had the answer to that by using the > 50% gray layer with Mode: Difference. > http://digital-photography-school.com/precise-color-cast-correction-with-gray-fill-layers > > snippet: > "This simple tutorial solves this problem by finding neutral gray in > the image, thereby removing the need to guess the color. In order for > this trick to work however, your image MUST contain 50% gray tone > somewhere in the image; otherwise the color correction will be off. > ... > The ‘Difference’ mode is a comparative layer mode that will invert > pixels containing 50% gray, turning those pixels black." > > I know there are many ways to achieve the end result, but part of > these tutorials is about learning and experimenting, so the knowledge > can be passed on. :-) >
I agree with you 100% and an important part of that learning is being able to discuss the various points raised. It does look as though that tutorial should help in finding a 50% grey area but, if there is a colour cast, then that area will never be a pure black and, of course, the grey area will not be a pure grey. Norman _______________________________________________ Gimp-user mailing list [email protected] https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
