Advanced Photoshop: Understanding Masks

Selecting specific parts of your image can be difficult, and editing them can be even more frustrating. In order to solve this problem, more advanced versions of Adobe Photoshop have introduced layer masks – which make editing individual parts of an image much, much easier. In this advanced Photoshop tutorial, you’ll learn how to create a gradient mask, as well as simple selection masks that you can use for any subject.

If you’ve already learned the basics of Photoshop and are looking for more advanced ways of using it, sign up for our advanced Photoshop course. Still a beginner? No worries, we have a class geared specifically towards those who are looking to master the basics first!

I have started with a simple photograph:

Screen Shot 2014-06-11 at 7.36.29 PM

Now, let’s say I wanted to darken the top part of the water, but leave the part near the people’s legs untouched – yet I wanted it to blend seamlessly together. Not a problem! If I were to try to darken the water without a mask, it would darken the entire image, which is not what I want to happen. To solve this problem, I’m going to use a gradient mask.

Let’s enter quick mask mode, which you can do by clicking on this button: Screen Shot 2014-06-11 at 7.38.07 PM found at the bottom of your toolbar.

Now click on the gradient toolScreen Shot 2014-06-11 at 7.38.48 PM If you can’t find it, click and hold on the paint bucket. You’ll find the gradient tool under that.

Click and drag from the top of the photograph all the way down to the bottom. Your photograph should now look like this:

Screen Shot 2014-06-11 at 7.40.07 PM

Now click on the quick mask button again. You’ll see that the bottom half of your photograph is selected. Since you wanted to edit the top half of the photograph, press Ctrl+Shift+I to inverse the selection. Now you can edit that portion of the water! While it looks like you could have just selected this portion with the rectangular marquee tool, you’ll see that it actually edits it in a gradient.

In order to darken the water, I’m going to open up my curves, which can be found above my Layers Palette here:

Screen Shot 2014-06-11 at 7.42.38 PM

I have dragged down from the middle of the curve, allowing the water to look naturally darker while leaving the bottom of the photograph untouched.

Screen Shot 2014-06-11 at 7.44.06 PM

You can see what my curves look like here:

Screen Shot 2014-06-11 at 7.43.39 PM

Oops! This is almost right, but you can see that the man’s knee was also affected by this change. Take a look at your Layers Palette, and you should see that your mask is now its own layer. This means that you can go back and edit that portion of the photograph anytime you’d like! Let’s fix his knee.

Click on your paintbrush toolScreen Shot 2014-06-11 at 7.46.23 PM Now, take a look at your foreground color. You’ll see both your foreground color and your background color at the bottom of your toolbox as two overlapping squares. Your foreground color is the one on top. If your colors are not set to black and white, hit ‘D’ on your keyboard and they’ll return to defaults. Now, make sure your foreground color is set to black. If it isn’t, press ‘X’ on your keyboard to swap them.

At the top of the screen, notice the dropdown menu for brush sizes and hardness levels. Make sure your brush is set to approximately 50% hardness.

Screen Shot 2014-06-11 at 7.48.23 PM

Now, make sure you have your mask layer selected, and begin painting on the portion that you don’t want affected by the curves. If the change is too noticeable, you can change the opacity of your paintbrush at the top of your screen. I have mine set to 64%. I have painted over the man’s knee, and you can see how it lightened it right back up, without affecting the parts of the water I darkened!

Screen Shot 2014-06-11 at 7.51.30 PM

What’s great about masks is that you can essentially paint them on and off in different opacities around your photograph in order to slightly tweak every single thing you want to tweak. Now, let’s say you want to edit the exact same part of the image you just masked, but you don’t want to have to select it again by using a gradient. Not a problem! Take a look at your Layers Palette, and take note of your mask layer.

Screen Shot 2014-06-11 at 7.53.48 PM

If you Ctrl+Click on the part that I circled above, you’ll see that your selection is back! Now you are free to edit it in any other way you’d like, and the edit you make will appear as a completely new layer as well, allowing you to infinitely edit each mask and each layer without affecting the original photograph.

Now let’s say you want to increase the contrast of the people’s legs. In this case, you’ll simply paint the mask on. Click on the quick mask tool again, and then click on your paintbrush tool. Make sure your foreground color is set to black, and then begin painting the area that you want to edit. A helpful hint: when painting, you can easily increase and decrease the size of the paintbrush by pressing the [ and ] keys.

Screen Shot 2014-06-11 at 8.01.32 PM

If you make a mistake when painting on your mask, don’t fret! Remember how you can paint the edit on and off? You can paint the mask on and off as well. Press X on your keyboard to toggle between black and white. When your foreground color is black, you’ll be painting on your mask. When your foreground color is white, you’ll be painting off your mask. It’s like magic!

Once you have your subject selected, click on the Quick Mask tool again, Ctrl+Shift+I to inverse your selection, and make your edit.

While you can certainly go right into Brightness/Contrast and increase the contrast, I like the control I have over contrast when editing it in Curves. I brought one side of my curve up, while bringing the other side down to increase the contrast.

Screen Shot 2014-06-11 at 8.03.52 PM

Now my photograph is exactly how I wanted it!

Screen Shot 2014-06-11 at 8.04.50 PM

You can make masks the same way using the Magnetic Lasso Tool, the Lasso Tool, or any of your other favorite selection tools. Remember: once you have the mask, you can easily alter it without having to make your selection again! You can use masks to change colors, alter contrast, add filters – the possibilities are endless. Each mask gets its own layer, so you can choose the opacity of your mask at will, or even delete it completely without affecting the original photograph. You can layer masks on top of each other and make multiple edits on one mask!

Practice makes perfect, so what are you waiting for? The more familiar you get with masks, the better you’ll be able to edit your photographs to make them look exactly the way you want.

For a more in-depth look at how to use masks to your advantage, Udemy offers an advanced course that will guide you through the steps!