How can I achieve consistent skin tones in my photographs?

Question

I've been shooting more people recently and have noticed that their skin tones are all over the map depending on the lighting situation. Are there any best practices or tips to ensure consistent and accurate representation of skin tones?

I am not sure if this is best addressed "in camera" or in post-production. I've been playing with the HSL settings in Lightroom so far to try and get the best results.

Answer 1

The short version of the answer to your question is that you do it both "in camera" and in post-production.

A longer answer breaks out into a few thoughts:

In Camera

1. Light the subject correctly. I really recommend using an incident light meter (a decent hand held one) to calculate the correct exposure for the subject rather than relying on the reflective light meter in your camera. This enables you to keep lights and darks correct rather than relying in the camera meter to pick the correct middle ground.
2. Get the correct color temperature. If you know what it is, and your flashes are accurate in temperature, then dial it in. Otherwise use a gray card to get it.
3. Makeup. There's a reason that professionals use it when under the lights, male or female. Makeup, especially foundation, helps to even out the skin tones and allows for contouring and shaping before you put light on them. A good makeup artist is really going to lighten the load on the post-processing side.
4. Comfortable temperature with the subject having sufficient time in location to have warmed or cooled appropriately.
5. Avoid clothing or accessories that apply pressure and are going to be removed before shooting. Otherwise give time to let the pressure marks fade.

After the Fact

1. Noise reduction, especially luminance, will blend and drop detail which will also smooth out skin tones. Do it carefully and use layers and masking so that you only effect what you want to effect.
2. Cloning good tone from the skin to the other parts is a pretty common, option. Do it slowly and with a ligth hand. Layers help here because you and opacity adjust as needed.
3. Dodging and burning, slowly and with a light hand, can even things out.
4. Frequency separation techniques allows you to work on the tones of the skin without impacting the texture. The linked video from Phlearn is a good place to start with learning this technique. It's quite powerful.
5. Portrait editing plugins to your favorite editor. I use Photoshop and Lightroom, so there are a ton for that. If you use something other than Adobe products, look around, but some of them offer a plug-in that also comes with standalone functionality. Word of caution, really soft touch with these is needed, they can be just way over the top in their changes if you're not careful. When I have used them, I pretty much turn off everything but the skin editing features.
6. Desaturate it. Nothing wrong with a black and white portrait and desaturation coupled with a bit of dodging and burning can turn a shot around quite nicely.

I'm sure that there's a ton more people can supply, but that's some of the things I've done or considered when it comes to portrait/people.

Answer 2

Warning: long meandering, speculative "answer" (and it may not even directly translate to Lightroom). In addition to the already described good practices for portrait photos, there's another subtle aspect that pertains to situations "in the wild" where the white balance you want for the image as a whole doesn't produce very pleasing skintones. I find this a lot in golden hour outdoor shots, etc. and it seems to be a psychological thing whereby we expect skin tones (maybe on people we know well, especially) to be "consistent" in photos, and not colored by light sources in a way that we don't object to in other objects (artistic effects aside).

This sense of "consistent skintones" is, I suspect, one of the things that camera manufacturers put a large amount of effort into when it comes to their in-camera processing. In fact, this was initially the one aspect of (Olympus) camera-produced JPEGs that I was more happy with than I was with what I could produce using darktable. Between that, and the fact that straightforward RAW development was able to accurately produce shades of orange that had always been a little too red in the camera JPEGs, it became clear that there was some fudging going on with colors that were just off of the "nice" hues (which vary surprisingly little among lighter or darker skin tones). After some messing around with the "color zones" module in darktable, I eventually came up with something similar (with the advantage that I can disable it when I want to) based on the following very slight tweaks:

• slightly increase saturation of the "nice" hues
• slightly decrease saturation of the adjacent "off" hues
• slightly shift the hues of these same "off" hues towards "nice"

all of which is constrained to a range of midtones where it seems to make the most perceptual difference, with the minimum effect on the image as a whole.

I'm blabbing about all of this because you mention playing with HSL values, and this is just basically a more refined way of doing this that can leave the overall colors of general images intact, without having to mess with portrait-style masking, etc. The effect is subtle, but it's as close to a "set-and-(mostly)-forget" operation without objectionable side effects that I've been able to come up with. If there's interest, I'll post the darktable style somewhere. It would be interesting to see what variations of it other people found pleasing, if any...