Lightroom gives you a million and one ways to complete most photo edits; after all, having options is important! No two photos are alike, so no two edits are alike either.
However, when it comes to correcting skin tones, I often like to use Lightroom’s color curves. In this article, I’ll show you what I mean – and how you can use color curves to handle skin tones in your own images.
By the time you’re done reading, you’ll be able to measure RGB skin tone numbers to give you a general idea of the edits your photo needs, and you’ll know how to handle any and all color issues using Lightroom’s color curves. Here’s the sample image that I use for color correction throughout the article, just so you can see what you can achieve:
Sound good? Then let’s dive right in!
How to find RGB numbers in Lightroom
The image below came out of the camera with a pretty good white balance and skin tone. Look to the histogram in the upper right-hand corner. Do you see those numbers under the histogram? Those are Red, Green, and Blue (RGB) numbers, and they correspond to the child’s forehead:
I’m guessing you’re already familiar with RGB values, but if not, here are the basics:
- Every pixel in your image is made up of three colors: red, green, and blue.
- For each pixel, the colors appear in different quantities, and these correspond to both color and tonal effects. An image that’s a bright red color will have a high Red (R) percentage but very little Green (G) and Blue (B) percentages. An image that’s a mid-gray color, on the other hand, will have 50% values for Red, Green, and Blue.
- Higher percentages correspond to lighter tones, while lower percentages correspond to darker tones. An image with only 100% values for Red, Green, and Blue will be detailless white, while an image with only 0% values for Red, Green, and Blue will be a deep black.
Displaying the RGB numbers for your photos is very useful, as we’ll soon see. It’s also quite easy! In Lightroom’s Develop module, hover your cursor over the area you want to measure. Then look under the histogram for the corresponding RGB measurements.
(Note: RGB numbers are usually measured on a scale of 0-255, but in Lightroom, you generally see them on a percent scale.)
For my image above, I hovered my cursor over the child’s forehead. I’ve added a small arrow to the image so you can see exactly what I measured. My numbers tell me that the pixels next to the arrow had the following RGB values:
- Red: 73.1%
- Green: 67.1%
- Blue: 60.5%
In other words, the child’s skin is more red than green or blue; it’s also on the brighter side but not so bright that it’s overexposed.
Using RGB values to analyze skin tones
When analyzing RGB numbers for skin tone, look for the following indicators:
- Red should be higher than Green. Green should be higher than Blue. This pattern is universal to all skin tones, regardless of age or ethnicity.
- Each color should have at least a 2% difference – usually more – between it and the next number. Do you know how to identify a pure gray? That is a pixel that measures exactly the same in its Red, Green, and Blue numbers. So skin with RGB numbers that are very close to each other is going to look gray. Not very natural or appealing, right?
- If any colors measure 94% or above, you probably have overexposure to deal with.
- If any colors measure 6% or below, you probably have underexposure to deal with.
The RGB numbers in my example photo of the child are consistent with expectations. That means the skin is at least relatively well exposed and has a good white balance.
What happens, however, if your photo doesn’t look so good straight out of camera?
For this next photo, I used the Lightroom histogram to measure the RGB values just next to the arrow on the woman’s forehead:
The numbers were Red: 93.8%, Green: 92.5%, and Blue: 93.6%.
Anytime you see a photo with skin tones that have RGB values like those, your eyes are going to tell you that something is off before the numbers do. But the benefit of using the numbers is that they give you a sense of how you’ll need to edit the image so the skin tones can be improved.
The numbers in this photo are concerning because, as I explained above:
- Anything higher than 94% or so is bright enough that a print from that image might not render good detail in those areas.
- Blue is higher than Green. Red should always be the highest and Blue the lowest; otherwise, the skin will appear cold.
- The RGB numbers are too close together, which means they’re approaching gray. As a result, the skin in the photo is lifeless.
How to correct skin tones in Lightroom
To fix this image, you should start by tweaking the exposure. Proper exposure is a huge component of proper skin color. In fact, it’s often impossible to assess skin tone issues effectively without correcting the exposure first.
A little-known bit of Lightroom awesomeness is that it’s easy to correct exposure while keeping an eye on the RGB numbers. In the Develop module, double-click in the numeric entry field for Exposure so that the number is highlighted. Next, hover your cursor over the area of skin you have been measuring (but don’t click!). Use the up or down arrows on your keyboard to change the exposure until a more appropriate measurement for the Red value appears under the histogram.
You can adjust Highlights (or Shadows, Whites, or Blacks) in the same way. Activate the numeric input field for editing, then hover the cursor over the point you want to measure. Use the arrow keys on your keyboard to increase or decrease the adjustment.
As you can see, I’ve used this method to improve the skin tone exposure:
However, the color is still off. You can try to fix the issue with Lightroom’s white balance sliders, but in my experience, when the RGB numbers are as close together as you see here, it’s often better to use color curves.
Color curves vs white balance sliders for correcting skin tones
Lightroom’s color curves feature has two major advantages over the white balance (WB) sliders.
As you know, Lightroom measures three colors (red, green, and blue) for each pixel. The white balance sliders don’t allow you to target the most important component of skin color: red. You can, however, edit the red tones using Lightroom’s color curves.
The other big benefit of using color curves is that you can adjust colors in limited parts of the image’s tonal range. If you reduce yellow in an image using the basic Temperature slider, you’ll reduce yellow globally (i.e., everywhere in the image). With color curves, however, you can reduce yellow only in the shadows, highlights, or midtones – without taking away the yellow that properly belongs in the other parts of the shot.
Using color curves in Lightroom: the basics
To find Color Curves in Lightroom, scroll down to the Tone Curve section. By default, it should show you the point curve, which looks like this:
(If you can’t see the Lightroom point curve, simply click the white circle at the top of the curve.)
Note that the default curve is designed to edit the tones in your image, not the colors. So if you click on a portion of the curve, and then drag it upward, the corresponding tones in your image will get lighter. The colors won’t change – for that, you’ll need to select one of the color channel options at the top of the panel:
As soon as you select one of these options, the curve will change to display a red-cyan, green-magenta, or blue-yellow curve.
At this point, you may be confused by the number of channels; after all, what if you need to adjust a color other than red, green, or blue?
Think about it like this. Each of the three colors measured in Lightroom has an opposite:
- Red is the opposite of cyan
- Green is the opposite of magenta
- Blue is the opposite of yellow
Reducing any one of those colors using the corresponding color curve increases that color’s opposite. In other words, reducing blue is the same as increasing yellow.
Now, looking at the curves panel, do you see the histogram behind the straight line? When you click and drag the straight line to create a curve, this tells Lightroom to adjust the pixels corresponding to that part of the histogram.
Say, for instance, that you wanted to add blue to the midtones of an image. You would select the Blue channel and click the line in the middle of the histogram, where the midtones live. Dragging the line upward would add blue to the bright parts of your photo’s tonal range.
Because dragging the curve upward increases the color the channel is named after – blue, in this case. And if it increases blue, that means it decreases blue’s opposite: yellow.
Dragging the curve downward, on the other hand, decreases the color the channel is named after.
Using the targeted adjustment tool for more precise results
That’s the way it works in general. But you can get more precise color control by using Lightroom’s targeted adjustment tool. Click on the button at the top left corner of your Curves panel to activate it:
Hover this tool over the spot you’re using to measure the skin tone in your photo, but don’t click! Use the up and down arrows on your keyboard while keeping an eye on the RGB numbers beneath your histogram until both the appearance of the photo and the RGB numbers improve.
Moving the blue curve down, as in the screenshot below, provides better separation between the Green and Blue measurements. It also gives the photo the warmth it’s lacking:
If the image still lacks vibrance, as this one does, move to the Red curve and increase the Red channel. Adding a touch of red is the best way to counteract gray skin.
Next, decreasing green (to add magenta) makes the skin color, as well as the corresponding RGB numbers, look just about right.
Making final tweaks
Once you’ve made your skin tone corrections using the color curves, you may find that things are better, but you should still take some time to evaluate the skin tones in particular as well as the scene as a whole. I recommend spending a few minutes away from the computer before you declare an image finished; it’ll give your eyes time to adjust.
Looking at my image, the warmth of the background plants is overpowering the subjects. To downplay it, I’m going to return to the Blue channel. Then, using the targeted adjustment tool, I’ll add Blue to the shadows by hovering over a dark area of the photo and hitting the up arrow on my keyboard:
Looking good! Compare the original and edited photos here:
Editing skin tones with color curves: a few final tips
When editing your own images, keep the following advice in mind:
First, to anyone who has heard that using RGB numbers to edit will solve all skin tone problems, that is simply untrue. There are as many proper RGB measurements as there are people in the world. As you study RGB numbers, let trends in the numbers and generalities guide your edits, but don’t try for an exact numeric match.
Second, measure skin tones in the middle range of brightness. Look for midtones to use as a reference point rather than bright highlights or deep shadows. Also, avoid measuring on cheeks, the end of the nose, or other areas that are usually redder than others.
Third, in general, when I’m editing photos, I look for tones in these ranges:
- Red is highest; Green is in the middle; Blue is lowest. This should always be true.
- The Red channel is usually between 70% and 90%. Very light skin can be as high as 94%. Very dark skin can go as low as 40-50%.
- The Blue channel is usually between 30% and 80%.
- It’s not possible to generalize how many percentage points difference should be between Red and Green or Green and Blue. However, skin that has warmer tones will have less Blue in proportion to Red and Green.
And finally, remember that small movements of your tone curve impact your image dramatically. Don’t go overboard!
Edit those skin tones for natural-looking portraits!
Studying the patterns in the RGB numbers of your photos is a great way to develop your editing eye. Everyone takes photos that aren’t quite right, and everyone struggles to determine what needs to be fixed, at least at first.
Analyzing the relationship between the numbers and the appearance of the photo will help you get to the point where you can eyeball a photo and determine what needs to be done without referring to the RGB numbers.
Now over to you:
What do you think about this method for correcting skin tone in Lightroom? Share your thoughts in the comments below!
