Auto Correct has always been a hit or miss. With CS6, the algorithms of image adjustment tools have been updated in CS6. Brightness Contrast, Curves and Levels have a new default option “Enhance Brightness and Contrast.” This option gives you access to all the values Photoshop chose by default. It’s a great way to get a good start, then fine tune from there. The other 3 options work on a channel by channel basis.
To experiment with the new Auto Color:
- Open an image
- Add a new Curves Adjustment layer.
- Hold down the Option (Mac) or Alt (PC) key and click on the Auto button to view the following algorithms:
- Enhance Monochromatic Contrast (the same as Image > Auto Contrast)
- Enhance Per Channel Contrast (the same as Image > Auto Tone)
- Find Dark and Bright Colors (the same as Image > Auto Color)
- Enhance Brightness and Contrast (new in CS6–and applied to the whole image, not a channel-by-channel basis)
Note that if you strictly want Photoshop to adjust the tonal range, and leave your color intact, change the blending mode of the Adjustment Layer to “Luminosity.” Also, if you if you want the color correction without affecting tonal range, change the Blending Mode of the adjustment layer to “Color.”