For this example I have used the curve saved earlier after adjusting brightness and saturation, but without the saturation inversion or anchor. The resulting colour may not be to everyone’s taste, but the technique is important. Note that in the histogram the output sides of the control arrows overlap and are at this point clear.
In the example images towards the end of the article, I have included some examples of this technique, usually with a few colours preserved. If after this manipulation, you find the colours a little way from where you’d like them to be, either use the color correction transform for fine tuning – or enlarge the color curves transform window and tune from there by moving the output arrow heads. I find color correction easier to use for finer adjustments.