levels

[Mark D Segal]

Oh, Tim, there's more to match that. When I was a kid contributing to my income with part-time work at a photo retailer in downtown Montreal an angry customer wanted her money back because the flash unit we sold her failed to light up the city when she took a night shot from the top of Mount Royal; or the story from a late cousin who was a manager at Eastman Kodak's Information Centre in Grand Central Station New York - after carefully explaining to a suspicious customer why the image appears upside-down on the ground glass of a view camera the guy told him he had to be the most stupid person he ever met.

You see why I think there's lots of time for people who ask what may superficially seem to be obvious questions about histogram manipulation in Photoshop.  

[howard smith]

EricM, when I was in school, I had a few (not many) rude and arrogant professors.    I was not in school to be reminded that I needed an education.  If you set yourself in life to be a teacher (or, in Jonathan's case, appoint yourself Teacher) you must expect to find some folks less educated than yourself.  And among those less educated, you will find different levels of ability and desire to learn.  You should accept that or change professions.

[Ben Rubinstein]

For all that Jonathan apologised, just be glad it's not Didger on heat.....  :p

[Jack Flesher]

As for HOW to accomplish keeping the color balance in check when adjusting the curve channels independantly, here's one method:


You can tweak and adjust the individual channel curve points in any fashion you desire.  This in and of itself will most certainly alter the color balance.  HOWEVER, if you first make a layer, then make all the curve adjustments on the layer, you can change the blend mode of that layer to "luminosity" and the overall color-balance will remain the same as the original and only changes to the luminosity of the image will be made.  (Alternatively, you can run the curves dialog on the main layer, but right after you hit "okay" go to "edit> fade curves" and here you can again set the blend mode  to luminosity. )

Cheers,