I've noticed that there is quite popular style of moody photographs with rich shadows, muted colors and very specific brownish-like skin-tone. It does seem to come from some kind of post-processing technique. What are the ways to achieve similar look?
Similar look can be achieved by applying an effect called Bleach Bypass. It originated in cine industry, where bleach bath was bypassed or shortened during processing of traditional silver halide cinematographic film. This effect and its variations are still popular in movies.
When regular film is processed, the developer bath simultaneously creates black and white color image at the same time. The black and white image is normally unwanted and removed by the bleach. So if you skip the bleach, you end up with film that has black and white image superimposed over color image with dark shadows, higher contrast and subdued color.
This can be successfully imitated in digital environment. One way to create it is to duplicate the image, make the copy black and white and superimpose it over the color original with overlay or soft light blending mode. There are many variables that you can manipulate to your taste (blending mode, transparency of the b&w layer, added noise, b&w conversion parameters, namely color blending, etc.).
A good way to find "how do you achieve this effect", is to try to reverse the process. Usually, it is not perfectly possible as many operations are destructive, but we can try to have an approximate idea.
- There is a lot of work on the tones here. We can play with the "levels" tool to obtain an image with flat tones. It is particularly difficult here because the tones inside the car have nothing in common with the tones outside. I chose to focus on the inside. The shirt on the guy's neck is supposed to be white, so we can set the white balance by setting the "gray point", which boosts the reds and reduces the blues :
- As you said, there are lots of shadow in this image. We can thus try to boost the dark area with the "curves" tool :
- Hum, the mood is still far from neutral... Let's get this guy his smile back !
The joke aside, the mood of an image is a lot more than post-processing. The composition plays a determinant role. The tilt of the head, the face, the emptiness and darkness of the inside contrasting with the outside lights reflected on the glass, etc.
Your question reminded me of Dan Winters' portrait of Christopher Nolan in Wired. See here for examples of DW's style:
The lighting techniques and post processing steps are described in this video (15 min):