The HSL tab is appropriately named: H = Hue / S = Saturation / L = Luminance. By default, the Luminance tab appears when you click on the HSL icon. To access the HSL tab, click on the icon that is housed in the red square on the accompanying image. Click on the Saturation tab to control saturation and the Hue tab to control the hue of given colors.
The sliders in the Luminance tab allow you to darken/lighten individual colors based on the provided choices. Move the slider to the right to lighten a specific color or to the left to darken it. In the image of the wood duck, I exposed for the shadows because my primary subject was not directly lit. As a result, the brighter portions reflected too much light and appear too light in the image. If I made a global change to darken the bright areas, the subject would be too dark. SOLUTION: Open the HSL tab and control the luminance of colors that are overexposed. In the BEFORE image, the exposure on the duck is spot on but the reflected blue sky and fall color are too bright and draw the eye away from the duck. With the luminance tab active, move the orange, blue and aqua sliders to the left to darken those values. The result is an image where the eye is now more drawn to the wood duck. The same principal applies if you want to darken or lighten red, orange, yellow, green, aqua, blue, purple and magenta.
The sliders in the Saturation tab work the same as in Luminance except the saturation of each color can be enhanced or subdued. For instance, you are in the red rock country of Arizona and a crystal clear sunrise strikes the textures, shapes and arches of the land formations famous in the state. The saturation of the oranges/reds is overwhelmingly vibrant. You check your histogram at the time of capture and find you need to compensate the exposure by minus 1.5 stops to not blow out the red channel. When you upload your images to your desktop, the oranges/reds are still over the top in saturation but the blue sky and other colors are perfect. If you make a global change to saturation in the Basic tab, the blue sky and other colors lose their impact. The solution is to go to the HSL tab and remove some saturation in just the reds, yellows and oranges until the image looks natural. Move the slider to the left to decrease the saturation or to the right to increase it.
The sliders in the Hue tab are a bit more complex. Rather than enhance or reduce the intensity or density of specific colors, they alter the hue of color families located on a color wheel. Look at the Yellow slider in the HSL tab as an example. On a color wheel, to the right of yellow is green and to the left is orange. On the yellow slider in the HSL tab, to the right is green and to the left is orange. In keeping with this, if you move the yellow slider in the Hue tab to the right, anything that’s yellow will shift toward green. If you move it to the left, anything that’s yellow will move toward orange. Study the background colors on each slider and you will see how colors shift. As one more example, move the blue slider to the right to shift blue to purple and to the left to shift it to aqua. In the realm of photography, shifting the hue of a color family can be beneficial. For instance, if you plan a fall color outing and arrive a bit before the colors peak, use the sliders in the HSL tab. The greens that are just starting to change can be tweaked toward yellow. Move the green slider to the left. The yellows that appear are a bit weak but can be shifted toward orange. Move the yellow slider to the left.