Skin tone might be the most discussed and sought-after creative aspect of motion images among filmmakers.
We painstakingly organize lenses, cameras, lighting, and color grading tools strictly by this single factor — and for good reason. Faces and skin are present in the majority of images we shoot, and they’re generally the most important feature that draws the viewer’s eye.
Why? Because our eyes are highly adapted to evaluating skin tone.
Humans are fine tuned to the details of other humans, and we pick up on even minor visual variations from what our brain tells us it should look like. We may not know the precise color a particular house, or garment of clothing, or landscape should be, but we know exactly what healthy skin looks like.
So it’s our right (even duty) to be so preoccupied with skin tone. Poor quality skin tones can communicate something about our characters and stories that we don’t intend.
That said, great-looking skin tone is an elusive, mercurial ideal, especially when we step into the world of digital video workflows. We may recognize what healthy skin tones look like, but figuring out how to get it is something else entirely.
In today’s article, we’ll look at five strategies for achieving pleasing and lifelike skin tones.
Contents
What is skin tone?
Before we dive in, we need to clarify some definitions.
One of the reasons skin tone is so misunderstood is that the term itself is a bit of a misnomer. In virtually any other context in color grading, “tone” refers to the contrast or brightness component of our image.
Terms like tone mapping, tonal ranges, and split-toning all refer to the grayscale curve of our image, rather than color properties like hue or saturation.
But when we talk about skin tone, hue and saturation are actually the two biggest factors, with contrast and brightness coming in at a distant third.
So for the purposes of our discussion, I’m going to define skin tone as the reproduced range of hues and saturations in our subject’s skin.
How do we get lifelike skin tone?
Now that we have a baseline definition for skin tone in general, let’s go further and quantify what exactly makes it “good” or “bad?”
It turns out this is simpler and less subjective than you’d think. Regardless of ethnicity, pigmentation, or complexion, healthy skin occupies a remarkably narrow range of hues and saturations. Thankfully, our brains respond very precisely to this range, so finding the boundaries is almost diagnostic.
Assuming we want to make our talent look healthy (which isn’t always the case!), we can define “good” skin tone as hues and saturations that correspond to our memory color for healthy skin. We can chart these hues and saturations using a vectorscope, and they fall around what is called the “skin tone line.” The more our subject’s skin falls outside this band of hues and saturations, the less pleasing it will appear to the average viewer.
So what happens if the skin tones drift to either side of this range? If hues become too saturated or drift toward red, subjects can begin to look blotchy, almost intoxicated or over-exerted. And if they become too desaturated or drift toward yellow, subjects may appear pale, sick, or malnourished.
One important caveat here: Skin, like any other material, reflects the light it’s illuminated by. That means the level of illumination on skin radically impacts the visual presence of different hues, and our perception of them.
This means that in scenes lit or graded with a strong “wash”, skin will reflect more of the “wash” color, and may fall partially or fully outside its normal range of hues and saturations. This is especially true of paler complexions, as they reflect back more of the light they’re being illuminated with.
Of course, this look is often used stylistically, so if you’re lighting or grading in this way, skin tones will fall outside the normal range. Attempting to preserve a neutral skin tone in these scenarios leads to brittle, unnatural images.
How do we get lifelike skin tone?
Now that we understand what skin tone is, and what makes it look lifelike and pleasing, let’s dive into our strategies for consistently nailing it.
#1 Use a color-managed workflow
The best single thing you can do for your skin tones is to use a color-managed workflow. But what does that mean?
A color-managed workflow (such as ACES) is one that accounts for the color space of your source material, and technically transforms it into the color space of your display.
This used to be a far less critical aspect of color correction, because digital cameras captured images in the same color space as our displays (Rec. 709). But as the dynamic range and color gamut of our cameras has improved, we’ve been overwhelmed by dozens of manufacturer-specific color spaces such as REDWideGamutRGB Log3G10, Arri Wide Color Gamut LogC, and Sony S-Gamut/S-Log3, to name just a few. This affords a ton of flexibility and creative opportunity in post, but it also creates the need for robust color management.
When you choose to work without color management, you’re forced into making subjective compensations and best guesses in order to brute-force your source material into your display’s color space. These compensations take longer and yield inferior results when compared to proper technical mapping, leading to inconsistent, mismatched shots.
By contrast, when you properly set yourself up with a color-managed workflow, the overall consistency of your grade (and your skin tones along with it) instantly increases. Color management eliminates 60-70% of the “problems” in a grade that are really just a matter of correctly mapping between two distinct color spaces.
Proper color management lets you focus more on the creative aspects of your work, and will give you much better consistency and accuracy when reproducing skin tones.
#2 Use your scopes
If you’ve spent any time at all in a grading suite, you know that our eyes lie to us.
Even if we tightly control variables such as ambient lighting and surround colors, we still have to battle our own chromatic adaptation. Our eyes are not objective, and we have to fight our biological vision system if we want to critically assess colors.
This means that for the fine-tuned adjustments involved in refining skin tone, it’s especially important to use our scopes as a reality check — specifically our vectorscope.
Even if you can tell by eye that there’s something off about your skin tone, the first step in dealing with this is to identify the problem with help from our scopes. Most vectorscopes have a built-in skin tone indicator line, which displays the accurate hue angle for neutrally-lit skin.
Checking skin tone inside DaVinci Resolve:
- Create a new node and draw a circular power window over a patch of well-lit skin — foreheads and cheeks often work best. Try to get as clean a patch as possible by excluding hair, eyes, mouth, and background.
- Click the magic wand at the upper left corner of your viewer to enable Highlight mode — this will grey out the entire image except for the inner contents of your power window.
- Open your vectorscope, and ensure your skin tone indicator is enabled. To do this, click the slider icon at the upper right of the vectorscope, and click “Show Skin Tone Indicator”. Evaluate the location of the signal in relation to the skin tone indicator — a patch of neutral skin tone should rest somewhere on top of this line, rather than too far to the right or left of it.
Note: if you’re working in a color-managed workflow as suggested earlier, you’ll get the best results out of these skin readings by placing your node downstream (to the right) of your output transform, and making your adjustments upstream (to the left) of it.
This is a quick test you can run as often as you like, particularly in your first pass when you’re dialing in your overall balance and look. If your skin tone lands in the correct region, you’re in good shape. If it’s falling considerably left or right of the skin tone indicator, or running at a different angle, read on!
#3 Use the broadest possible tools
Ok, so you’ve identified an issue with the hue of your skin tone, and you want to remedy it. What’s the best way to go about this?
The most important thing to remember when fine-tuning skin tone is to avoid the all-too-common trap of thinking in terms of correcting. What we really want to think about is neutralizing.
What’s the difference?
If you’re on a road trip, and you lose pressure in your front left tire, you’re going to feel the car start to drag in that direction. You might correct for this by cutting your wheel to the right. But to neutralize it, you need to pull over and put some air in that tire.
Similarly, if we’re working on a shot, and take a reading to discover that our skin hues are falling to the right of the skin tone indicator, our first instinct might be to pull an HSL qualifier or other secondary to correct the skin back to where it belongs.
But the cleaner approach would be seeking to neutralize the issue with a simple primary adjustment — in this case, adding some green gain to move the entire signal to the left. This “broadest possible tool” approach will yield cleaner, faster, and more repeatable results, and you’ll be amazed at how often a simple primary adjustment is all that’s needed.
Less-common fixes
But what about those rarer scenarios where an overall primary adjustment is too broad, and adversely affects the rest of the image? We simply continue looking for the broadest possible adjustment.
This can be accomplished in the Custom or Hue vs. Hue curves, where we can focus our adjustment on a particular tonal or hue range, rather than on the entire image.
If we find that these tools are still too broad for our needs, we can narrow things further by using an HSL qualifier. However, instead of making a narrow selection by qualifying our hue, saturation, and luminance range, we make the broadest possible selection by attempting to pull our key using only one or two parameters.
The best way to do this is to manually set your ranges in the qualifier, rather than using your eyedropper to sample the image — the latter will always leave you with an overly-narrow selection.
Instead, work through each parameter individually, starting with luminance, and only narrow your selection as needed. As before, this approach yields cleaner, faster, and more repeatable results, which is especially important with qualifiers due to their tendency to introduce noise and artifacts.
Incidentally, this concept and descending priority of tools are great options for any grading task, whether you’re working on skin tone or not:
- Primaries
- Custom curves
- Hue vs Hue curves
- HSL qualifier using as few parameters as possible
With this approach for dealing with issues at the shot level, let’s move on to two strategies we can use at the global level to ensure pleasing, lifelike skin tone.
#4 Use split-toning
Split-toning is a powerful technique with many benefits, including adding depth, color separation, and color harmony to your images.
But split-toning is also a great way to globally “pop” skin tones.
Since the technique involves adding cool colors to shadows and warm colors to highlights, it can subtly bias the middle and upper exposure ranges where skin most commonly lives toward the typical hue. And since these hues are remarkably consistent across ethnicities, pigmentations, and complexions, split-toning is a viable technique for most any subject.
The trick here is to ensure that your warm push has the right mixture of red and green to give accurate skin hue. Here’s an easy way to do this inside Resolve:
- Create a grayscale ramp by going to your Edit page and clicking “Effects Library” at the upper left. Select “Grey Scale” and drag it into your timeline.
- Right-click on the Grey Scale ramp in the timeline, and select “New Compound Clip”. Set the pop-up name field to “Ramp” and click Create.
- Return to your Color page and select the ramp as your active clip.
- Go to your Color Wheels and set your Lum Mix to 0.
- Go to your Custom curves and un-gang your YRGB channels.
- Build the top of your split-tone curve by adding control points for red and green toward the top of the signal, and push both upward. Find the right ratio of red to green by ensuring that your signal is moving roughly along the skin tone indicator in your vectorscope. Once you find the right combination, you can always back off the intensity of your red and green curves using the sliders to the right.
- Build the bottom of your split-tone curve by adding control points for blue and green and pushing upward.
After you’ve built your initial recipe in this way, you can audition it on individual shots and further fine-tune it, taking care to preserve the relationship between your red and green control points at the top of the curve.
Once you’re happy with the look, you can copy/paste this node onto individual shots, or apply it to all shots to give yourself a consistent global look.
To save you some time, here’s a link to a PowerGrade for a pre-built split-tone curve.
#5 Compress nearby hues
In addition to biasing skin toward the accurate color tonally by using split-toning, we can use the Hue vs Hue curves to compress skin-adjacent hues into a smaller range around the skin tone line.
This provides a sort of “bumper” for skin tones that drift outside the typical range, without adversely affecting the rest of the hues in our image. Here’s how to do this inside Resolve:
- Load in an image containing a ColorChecker chart, and go to the Hue vs Hue curves.
- Use the eyedropper tool to sample the “orange-yellow” patch at the far right of the second row, then move the control point 7-8 degrees upward.
- Use the eyedropper tool to sample the “orange” patch at the far left of the second row, then move the middle control point 5-6 degrees downward.
As with our split-toning curve, this hue-compression node can be copy/pasted onto individual shots as needed, or onto all shots to add further consistency and polish to your skin tones.
Wrap up
Most of what we’ve discussed today revolves around using our scopes for objective feedback, but remember that your eye should be your ultimate guide.
If your skin doesn’t meter quite right but the shot feels great, there’s no law that says you have to change a thing.
My goal is to equip you with the right tools for assessing and adjusting skin tone as needed. However, these techniques should complement rather than replace your creative impulses — color grading should never become a “paint by numbers” proposition.
Of course, there may also be instances where you specifically don’t want neutral skin tone. For example, in “color wash” scenarios like I mentioned earlier, or in situations where you want a character to appear sick, intoxicated, pallid, or subject to unflattering lighting.
In these cases, you can apply the same concepts, but endeavor to move their skin tone off of the skin tone line, rotating toward yellow or red, or pushing toward magenta or green. There’s tons of room for experimentation here.
With practice, these concepts will set you free to make intuitive adjustments, so that you can finesse your skin tones for maximum effect on screen. Happy grading!
