Saturation mask, in my opinion, is very under-utilized.
We tend to focus on the big things...like luminosity masks, color grading, etc...sometimes forgetting the fundamental stuff.
In case you don’t know what a saturation mask is, it’s a layer mask that isolates the most saturated part of the image.
Just like any layer masks, the most saturated areas are revealed in white and unsaturated concealed in black.
You can then apply color adjustments targeting only the most saturated (or unsaturated) part.
In this post, we’re going to dive into saturation mask, why it’s worth your time and how to use it for color correction in post-processing.
Why Saturation Matters
Saturation, also known as chroma in color theory, is what makes colors stand out.
We (humans!) tend to be attracted to more saturated colors.
But having more than one saturated color within an image is not always a good thing because they start competing for attention.
Now Imagine an image full of tulips blooming in the spring. People love tulips because they are exceptionally colorful.
Note I said “colorful”? That’s how we describe saturated colors...you don’t hear people say “look how saturated those flowers are”. (LOL!)
What if we start desaturating these flowers.
Would it still be as visually appealing?
Of course not…
That, is the power of saturation.
What Is Saturation?
Saturation is the purity or intensity of a color. It defines a range from pure color (100%) to gray (0%) at a constant lightness level.
Although saturated colors look pretty, nothing in real life actually exists in pure color.
This is why highly saturated images (like over-processed HDR) look unnatural and fake.
So, what affects saturation?
White and gray but not black.
Let’s look at some examples:
Here are three color gradients, from pure red (RGB 255,255,255) to white, black and gray.
Pay attention to the HSB (hue, saturation and brightness) value in the box (blue arrow).
In the red to white gradient, saturation reduces as we move from red to white. This is the same for the red to the gray gradient.
But for the red to black gradient, saturation maintains at 100% across. Then it drops from 100% to 0% as it turns to pure black.
This means adding black only reduces the light level but not the saturation of the color.
**I think I went off on a tangent here, but I didn’t want to delete this part because I thought it was interesting!**
How To Create 16-Bit Saturation Mask
Unlike luminosity masks, there isn’t a dozen masks you can choose from.
In essence, you only need one. You can run a few variations but it all based on the one mask.
A more detail version can be found on Tony’s website...but here’s a summarised version:
- 1Load image in Photoshop.
- 2Add a Selective Color adjustment layer.
- 3In the Properties Panel of the adjustment layer, select Absolute at the bottom.
- 4Click the dropdown menu, move the Black slider to -100% for the top six colors (reds, yellows, greens, cyans, blues, magentas).
- 5For the bottom three colors (whites, neutrals, blacks), move the Black slider to +100%.
- 6Go to Channels Panel, click on any of the RGB mask (all identical anyway). Right-click your house and select Duplicate Channel. Rename it “Saturation Mask”.
- 7Go back to Layers Panel, delete the Selective Color adjustment layer.
And there you have it, 16-bit saturation mask!
Don’t forget to save it as Photoshop Actions to automate these steps in your next edit.
How To Create Vibrance Mask
If you can remember color theory...
You should recall that vibrance controls muted colors, i.e. areas that aren’t too colorful.
Essentially, the vibrance mask reveals (white) muted colors and conceals (black) saturated colors.
Why do you need vibrance mask?
It allows you to target select vibrant areas in the image...you can then apply color adjustments accordingly.
And the best part is...
Vibrance mask is the inverse of saturation mask.
Simply invert (cmd/ctrl + I) the saturation mask you created and boom!
You have a vibrance mask literally at the snap of a finger.
What about HSB/HSL Method?
You may have come across another method to create saturation mask.
This is not a true saturation mask.
As you can see in the comparison below, the HSB/HSL saturation mask is very different from the true saturation mask.
In the HSB/HSL method, the foreground is included in the selection, which shouldn't be (saturation around 30%-40%).
Case Study 1: Unintentional Saturation
Sometimes it’s easier (and more effective) to show you in action instead of writing a long paragraph.
You might be wondering:
When am I ever going to use saturation mask?
Oversaturation...or should I say unintentional saturation is the case most of the time.
Take a look at this image below before and after highlight adjustments.
In this example, the Highlights adjustment in Lightroom was moved to the left to reduce the highlights in the sky.
This was done to recover the colors.
While that worked beautifully, it came at a cost…
Which is an increase in the saturation of the sky where you just toned down the highlights.
By the way, this is a common issue when applying tonal adjustments.
Check out the images below after adjustments with the Curves tool.
To fix the unintentionally saturated area (in this case, the sky) is easy.
Create the saturation mask with the steps explained above, or use the Photoshop Actions you’ve created.
Once you have the mask, you can either apply it directly to a Hue/Saturation adjustment layer or use painting-a-mask technique.
The latter has more control over how much and where exactly you want to reduce the unintentionally saturated areas.
Check out the before and after -14 saturation in Photoshop with saturation mask.
If you find the saturation mask “too revealing”, i.e. you only want to reduce saturation in a very specific part of all the saturated area…
You can double click (Photoshop CC 2019) the layer mask to refine it, or
Apply a Curves or Levels adjustment to the saturation mask by going to Image > Adjustments > Curves/Levels.
Click here to learn more about refining layer masks.
Case Study 2: Saturation Around The Sun
Not many of us actually realize this issue…
But once you know it, you’re going to start looking for it the next time.
When you shoot into the sun, the area around the sun always appears oversaturated.
I don’t know why.
If you do, leave a comment to enlighten the rest of us!
The Problem, Solution and Refinement
This oversaturated surrounding makes the sun looks like a fried egg!
Correcting it makes the image look more natural.
With saturation mask, this can be done in literally seconds.
The steps are exactly the same as the above.
If the saturation mask includes the sun itself, use painting-a-mask technique to target only the area outside the sun.
Case Study 3: Color Boost With Vibrance Mask
The trend nowadays leaning towards targeted adjustments.
We know it’s bad for the image to apply global adjustment, so we find ways to select only the areas we want to adjust.
For color adjustment, there’s no better way to enhance colors that really needed boosting with vibrance mask.
The steps are almost the same as explained.
If you have a saturation mask already, invert it.
Now, apply the vibrance mask to a Vibrance adjustment layer.
Because we’re now boosting the overall color of the image, you can apply color “globally” through the vibrance mask.
Check out the example below comparing the original image (before) and +60 vibrance with vibrance mask.
Just to prove that vibrance mask actually made a difference to the image, here's the comparison of +60 vibrance with (before) and without (after) vibrance mask.
Happy Saturation Hunting!
You may find yourself looking hard for unintentional over-saturation in all your images from now on!
But that's a good thing...
Because you're going to pay more attention to details.
Creating a good photograph is not about making big changes but small and subtle adjustments.
Saturation mask should definitely be on the checklist in your post-processing workflow.