How To Increase Contrast And Retain Luminosity?

I was wondering if there were any obvious, or less obvious ways to increase contrasts in an image without effecting the luminosity. I usually end up with a little flattening of the contrast in my images when trying to increase shadow detail. Is there a way to add back some contrast while retaining the shadow detail? Does anyone know anything about something called Chroma variance?

Thanks,
Chris

Chris,

Chroma is another word for saturation. Therefore, "chroma variance" would mean varying, or changing, the saturation level, either more or less saturation.

Regarding luminosity and contrast in the shadows, you may simply need to reset the black point after opening up the shadows. Look at how I do this in my current essay at:

http://www.naturephotographers.net/articles0209/ab0209-1.html

If that doesn't work you can try to do a local contrast enhancement, such as High Pass Contrast, also in my essay, or reverse unsharp masking. However, this will affect the whole image, not just the shadows.

Alain

Alain, would be willing to explain 'reverse unsharp masking'? That's not a technique I've heard of before.

Chris, if you haven't yet, take a look at Tony Kuyper's luminosity masks. They can give you an incredible amount of control over the contrast of lights and darks in an image.

I agree with Greg.
Tony's self feathering mask actions work on a broad variety of tones, from 'Super Lights' to 'Super Darks' without affecting any other aspect of the image.

I use this 'action' on almost every image and highly recommend them to anybody that likes to spend time optimizing their work to the fullest potential.

Another vote for Tony' masks.

Another vote for Tony Kuyper actions, they offer you a toolset of possibilities for post-processing.
Maybe what Tony calls "Luminosity Painting" could help you out as well, check his article here where he explains about it:

http://www.naturephotographers.net/articles0908/tk0908-1.html

Luminosity masks are a great tool. As is the editable Dodge/Burn layer. I think I read about that from Daryl Benson, have been using it for a while now and really like it.

Robert,

Reverse unsharp masking is using the Unsharp Mask filter in reverse, that is with a low % and a high radius instead of a high percentage and a low radius as is normally used for sharpening. Used this way it increases local contrast.

The "Clarity" control in Lightroom 2 is the same but under a new name.

Thanks Alain.

Re Chroma Variance, see Joseph Holmes profiles.

http://www.josephholmes.com/profiles.html