Tag Archives: luminosity

Post-Processing: A Shadow Recovery Example

(In another forum someone asked a question – actually, more like posed a challenge – related to how much usable detail and quality could be extracted from a raw file that contained areas of very low luminosity, as could happen with a badly underexposed image or with an image of a scene with a very large dynamic range. Since I went to the work of responding and illustrating my response, I figured that I might as well share it here, too. With minor revisions, here it is.)

First, I actually have a “real” version of this photograph in which highlights were slightly blown, but which I preferred to use since I could bring them back in post and get a bit more shadow detail to start with. (It looks a bit bright to me as an on-screen jpg, but it makes a fine print.) That photograph ended up looking like this:

Kolob Canyon, Morning - Morning light slants over the top of sandstone cliffs above early autumn foliage in Kolob Canyon, Zion National Park
Morning light slants over the top of sandstone cliffs above early autumn foliage in Kolob Canyon, Zion National Park

This photograph and the other I’ll move to below were both shot from a tripod with a Canon EOS 5D Mark II at ISO 100 using the Canon EF 24-105mm f/4L IS at f/16. While the “keeper” used for the photograph above had a 1/4 second exposure, the example I’ll use below was shot at 1/30 second.

The exposure challenge in this scene was the very large dynamic range between the bright spot of sky at the head of the canyon and the much darker colorful foliage in relatively deep shadow in the foreground. Exposing for optimal quality in the foreground would completely blow out the sky, while exposing for the sky would necessarily grossly underexpose the foreground.

I originally thought that I might like to have four bracketed exposures in case that would let me produce a better final image via layer blending, but it turned out to be unnecessary and the final image (as shown above) has a single source file with no blending. However, this means that I still happen to have one very badly underexposed (by three stops) version at 1/30 second which I’ll use here as the starting point for what I plan to illustrate in this post. Follow along with me and see what I can do with the very underexposed version of the file… Continue reading Post-Processing: A Shadow Recovery Example

Some Thoughts on Black and White Conversion in Photoshop

Every so often you run across an article that offers some unfortunate advice on an important subject – perhaps it offers outdated advice or suggests a less effective technique. I saw such an article today on methods for converting color digital images to black and white in Photoshop. Sometimes seeing such an article encourages me to write something about the same topic as a counterpoint – and that is what led to this post.

I cannot claim to be the master of this conversion process, and I recognize that there are several ways to do it that are both effective and different that what I’ll describe. In addition, this will be more or less an overview rather than a detailed tuturial. IN any case, I want to offer some ideas that might be a bit more contemporary, flexible, and powerful than those I read about in that article. Continue reading Some Thoughts on Black and White Conversion in Photoshop