The Simple Technique for “Cinematic” Color Saturation in DaVinci Resolve
I talk a lot about the untapped power of DaVinci Resolve’s Primaries tab and how we really need to be maxing out its tools before we move on to narrower or more complex adjustments. But there’s a knob right within this Primaries tab that I very rarely use, and that’s Saturation.
Is that because I don’t care about the color saturation of my grades? No. It’s because I don’t like what this knob does to my images. And as a result, I’ve developed other techniques for manipulating the overall colorfulness of an image when I’m grading.
So in this article I want to quickly show you a couple of those techniques and talk you through the principles that I like to keep in mind when I’m manipulating saturation in my images.
Color saturation principles in Resolve
As you can see from the screen below, I’ve set up a brand new project where I’ve done nothing at all except for the same two things that I always do at the very beginning of a project. I’ve set up my color management and I’ve set up the template node graph that you see here on my upper right hand side.
We’ll be looking at Color Management in a later article, but you can learn more about the node graph setup in the following video.
Maintaining your balance
The first thing that I want to emphasize before I even begin looking at how I’m going to introduce saturation into the image, is that balance starts to become really critical when you’re manipulating the saturation of an image—especially when you’re increasing saturation.
Essentially, if you have a small imbalance in your shot—like it’s a little too red or too green—that imbalance is going to become exaggerated as you start to add color into the image.
“Balance starts to become really critical when you’re manipulating the saturation of an image.”
So before you think about adding saturation into the image, you need to revisit your balance node and make sure that you’re completely happy with it. If you don’t then you’ll probably end up having to go back to that balance node and recalibrating to get a proper starting point. And that’s just wasting time and effort.
Finding the sweet spot
I use the same criteria for this every time, and that’s to optimize my skin tone and maximize my color separation. A useful rule of thumb for this is to check your vectorscope and try to get the signal mass so that it’s straddling at least two separate quadrants in the ‘scope
For example, below is an example where the color separation is really low because everything’s crammed up here into this upper left quadrant.
And the same here, with the colors all squeezed into the upper right.
So instead, try to adjust your image using the Offset ball so that the signal mass straddles these two quadrants while preserving your skin tone—that’s the first and bigger consideration. Once you’ve found this sweet spot, you’ll have separation and optimized skin tone. Now you’re in a much better position for adding color saturation into the image and getting good results.
Adding the color saturation node
So with that out of the way, let’s add a new Serial node after the balance node, using Opt/Alt+S, and take a look at the Saturation knob that you’re here for.
Let’s say your client has decided that they really want to max out the color ‘pop’ in whatever you’re working on. So you can go crazy with the saturation, but as you do this, ask yourself at what point does it go too far? At what point are you no longer getting visually enticing results?
Take this example…
It’s almost maxed out. And in technical terms, you’ll see in the vectorscope when you turn it off and on that you’re expanding saturation. In other words, you’re getting more colors spreading in all directions.
But there’s a point past which the image just doesn’t really look good anymore, right? It feels garish and weird. It feels very video. So be aware of this boundary as you work the saturation—it’s not just about getting a signal that looks good on a scope. It’s about getting an image that looks good.
When you’ve reached the point that’s as far as you’re comfortable with, grab a still of it and hit Cmd/Ctrl+D to disable the node while keeping a reference for comparison. Now it’s time to try something a little different.
Cinematic saturation in Resolve
We’re going to try implementing saturation in a very different, “cinematic” way. But it requires a couple of steps that I’ll explain as I go. First, create a new serial node (Opt/Alt+S), then right-click on the node, and select Color Space->HSV.
Next, right click on the node and select Channels, then turn off Channel 1 and Channel 3. This tells Resolve that, for the span of this node alone, you want to move out of a standard RGB color space or model and into an HSV color space or model.
In an RGB color model, we’re specifying a particular color by saying there’s this much red, this much green, and that much blue in it. And that’s similar to how we specify any color within HSV. But instead of red, green, or blue, we’re specifying hue, saturation, and value—with value being loosely equivalent to brightness.
And there are a number of reasons why we might want to do this, but one of them is so that we can explicitly manipulate the Saturation channel.
Now you’ve got a dedicated channel for it, which you don’t get when you’re working in RGB. That’s why we disabled Channel 1 and Channel 2 earlier, because Channel 1 is Hue, and Channel 3 is Value (brightness). So now all we have left is Channel 2—Saturation.
Working with a separate Saturation channel
Now if you adjust your Gain wheel you’ll get some very different results to the node we had set up at the beginning. Even when the level of saturation is similar, the image appearance is not. Though admittedly these are both exaggerated examples…
Despite this exaggeration, I feel that one is clearly better than the other. You might not—in which case, feel free to stick with the Saturation knob.
But if, like me, you prefer the second image, it might help you to think of it as subtractive saturation. Which is closer to how things work in the real world.
Apples to apples
Let me explain, if I have an apple of a certain redness, a certain saturation, and then I have a redder apple, an apple with more saturation standing right next to it, that second apple is actually reflecting less of the light hitting it. It’s absorbing more of the light. So by definition it’ll be a little bit darker than the first apple.
So if you take a look at what you did with your HSV node, you’ll find that when you turn it off and on, you’ll get darker areas of this image as they become more colorful or saturated.
That’s why I think it’s worth exploring and why, for me, it’s inherently superior to the more video-style saturation that you get from the more conventional Saturation adjustment, where your luminance will either be the same or brighter because of the math being applied when your dial the saturation up.
More control over your saturation
There are other benefits to the HSV node approach. For example, when you increase the saturation with the Gain wheel, it affects everything—low saturation, medium saturation, high saturation. They all get cranked up, which is the same behavior you get from the default Saturation knob.
But what if you want to be a bit more selective? What if you want to increase the saturation of lower color saturation areas without changing the higher saturation portions of your image?
That becomes really easy to do when we are in this HSV node. You could, for starters, just try adjusting using your gamma. When you turn your gamma to the right, it’ll increase saturation in the lower middle saturation areas without driving saturations that are already really hot making them look worse.
Custom color saturation curves
If you want to get even fancier, turn off your gamma, and head to your Custom Curves, where you can literally draw your own saturation curve. For example, you might only want to saturate the lower color saturation portion of the image without affecting the rest of the image, or you could make it more gradual—you could literally sculpt any saturation curve that you want to.
“An HSV node gives you the flexibility to sculpt a more nuanced approach.”
It’s probably not where you want to start, because custom curves can get more complicated and more time consuming than simply spinning gain or gamma. But it’s worth emphasizing that, in addition to having a model that can often feel more cinematic than the model used by the saturation knob, an HSV node gives you the flexibility to sculpt a more nuanced approach to the color saturation of your image.
There’s a lot more to it than just a knob that you twist left and right.
Color saturation is a huge, complicated subject and we can get way better or way worse results in our grades depending on how we tackle it. Before you develop your own style as a colorist, it’s one of the fundamentals of grading that you need to master. And the more you learn, the more you understand that there are really no rules, just a bunch of different alternatives.