One of the most useful tools you will find in Photoshop is the ability to edit using Layer Masks.
What is a Layer Mask? Essentially, it is a duplicate of the original image (or, in Photoshop jargon, a new "layer") where you can make edits without affecting the original ("background") image or layer. This is known as non-destructive editing. In other words: layer masks are a life-saver.
Also, if you make a mistake, you can quickly correct your mistakes without having to start over. Let me show you how!
First, create a New Adjustment Layer by clicking the icon highlighted below, the selecting Curves:
I am going to start off by lowering the curves in order to make the subject's hair stand out a bit more. Her hair, particularly the top, needs a bit more pop, so I reduced the Curves by pulling the center of the line down to the bottom right of the histogram. This gives her hair more depth:
Since I only want the curves adjustment to apply to her hair, I am going to create a layer mask to erase everything except the adjustments on her hair. Make sure that your Curves mask is set to Layer, not Vector, by double clicking the white rectangle:
With your Curves Layer Mask selected, make sure that your foreground color is set to black. With layer masks, black takes away/erases the adjustments you have made on that layer, while white puts the adjustments back in. So, if you are using black to remove adjustments and remove too much, all you need to do is change your brush color to white, and brush over the area where you removed too much.
Select a brush tool with a soft, blurred edge. For this image, I am using a fairly large brush, since I will be erasing the majority of adjustments, except for the small portion on her hair. When you are ready to begin erasing the adjustments, simply hold down your left-click on your mouse just as you normally would with a brush in Photoshop:
You can also adjust the Opacity and Flow of your brush in order to make the effect less noticeable. After erasing all but her hair, I felt as though her hair was now too dark, so I reduced the opacity of my brush to 75% and brushed over her hair once:
Another trick for softening the effect of an adjustment layer is to reduce the opacity of the entire layer. By reducing the overall opacity to 78%, I softened the Curves adjustments even further:
To make her stand out even more, I created a new Levels Layer Mask (just like I did with Curves at the beginning) and moved my highlights output slider to the left - this darkens the image, so in order to make the subject brighter, I am erasing the Levels adjustments on her, while leaving the rest of the image alone:
As you can see in the Layers panel, the black areas represent where I brushed over/erased the adjustments. So, on Curves 1, you can see that almost the entire rectangle is black - this is because I erased my Curves adjustments everywhere except her hair in order to give it more depth.
On Levels 1, you'll see that only the subject is black, while the rest of the rectangle is white. This is because I darkened everything except the subject with this adjustment:
To recap this crash-course in Layer Masks:
- Layer Masks allow you to make adjustments to specific sections of an image without overwriting your original/background image
- With the foreground set to black, you will be erasing adjustments and revealing the original background image
- With the foreground set to white, you will be putting the adjustments back in that you may have erased, and correcting any mistakes you've made while editing
- Use a soft edge brush
- Experiment with the Opacity and Flow of the brush, and the Opacity of the layer in your Layers Panel