Unit Six : The Art of Photography
Luminance was used to recover the soft colors of the sunset. 
Now that we've been introduced to the orders of the colors, let's look at their variables. Those who have post processed images in Adobe Lightroom, Apple Photos, Capture One, or any other RAW editor may be familiar with what is commonly known as the 'HSL sliders.' HSL meaning: Hue, Saturation, and Luminosity. Let's start with hue.
Figure 2a: Hue slider (Lightroom Classic CC)
Figure 2b: Saturation slider (Lightroom Classic CC)
Figure 2c: Luminance slider (Lightroom Classic CC)Hue
Hue simply is the shade or name of the color. In our editing programs, this slider allows us to completely change a color.
Watch what happens when I take this photo of an orange sunset and move the orange hue slider left and right.
Saturation
Saturation is the amount of color, or its intensity. This is how we end up with those selective color photos we all... er... love so much, but it can also be used to isolate the strength of one color over the others.
The photo in figure 2b consists of mainly 3 colors: blue, yellow, and orange. Watch what happens when I move each color's individual saturation slider.
Luminance
Luminance is the brightness of the color. This helps us bring out bright color, recover skin tones, and many other techniques.
In figure 2c you can see how the blues react to the luminance slider.