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Photoshop Tutorials For Beginners | Lesson 7: Using Photoshop Masks For Non-Destructive Edits
In this tutorial we'll be exploring the very powerful feature of Photoshop masks. We briefly touched on this subject in lesson 6 on adjustment layers, because layer masks are automatically applied to adjustment layers. But here we'll look at how layer masks can be used in other situations, as well as clipping masks. This will really take your post-processing to the next level. So let's get started...
Masking in a nutshell
What actually is masking? Well, masking is about hiding/revealing specific parts of a layer. In other words, choosing which parts of a layer are visible, and which are hidden. This is really simlple, but really powerful.
The essence of masking is that the colour black hides and the colour white reveals. So when you create a layer mask, which appears as a thumbnail in the layers panel, the black area will be hidden and the white area will be visible.
There are basically 2 different kinds of masking in Photoshop: layer masks and clipping masks. Often, either can be used to create the same effect. But we'll look at how both can be used in this tutorial.
Open an image in Photoshop and select the rectangular marquee tool (the 2nd item down on the toolbar). Drag out a selection in part of your image.
Now go to the Masks panel, or go to Windows>Masks to make the panel visible. Select "add a pixel mask" from the top of the Masks panel (the small square icon with a white circle in the middle).
Now click on the Layers panel and notice how a new thumbnail has appeared next to your image thumbnail. That is your layer mask. You'll see that the selection you made is white (visible) and the rest of the image is black (hidden).
You can change the density of the masked area by using the slider in the Masks panel. Try it - you should see the image returning as you move the density towards 0%.
It's also easy to invert the mask, by clicking "Invert". This makes our selection hidden, and the rest of the picture visible. In the layers panel, alt-click on the layer mask to see the main image in black/white. This gives you a full sized view of the layer mask.
The brush tool is an essential part of using layer masks. Make sure the layer mask is selected (by clicking on it in the layers panel) and select the brush tool, which is the 8th item down on the toolbar. With your foreground colour set to black paint over the white, visible part of the layer mask (our rectangular selection). You should see it disappearing and becoming transparent like the rest of the image.
Now change your foreground colour to white and paint back over the same area. The image re-appears in this area as you do so. This shows how masking is such an effective, non-destructive method. All changes can be quickly reversed.
Layer masks in practice
So, let's say that you have 2 images and would like to combine them. This is common with landscape photos, where it can be necessary to create an exposure for the sky and for the foreground separately.
Right exposure for the sky:
Right exposure for the foreground:
Open 1 image in Photoshop, and then add the other as a layer on top of it. We only want part of the top layer, the correct exposure for the sky, to be visible in the final image.
So select the top layer and add a pixel mask in the Masks panel. Alternatively, click on the square with a white circle in it at the bottom of the layers panel, as a shortcut. Now hide this entire layer, by alt-clicking on the layer mask (which fills it with your foreground colour, so make sure foreground colour is set to black).
Select the brush tool and choose a soft edged brush from the options bar at the top. Set white as your foreground colour and begin painting away the mask to make your top layer visible.
When merging landscape photos like this, I tend to finish by reducing the opacity of the brush to 25% and sweeping once over the boundary between the images, to make the blend more natural.
Layer masks with adjustment layers
As we saw in lesson 6 (Having Fun With Adjustment Layers), when you create an adjustment layer it automatically features a layer mask. This makes it very easy to quickly fine tune the adjustments by applying them to specific areas.
By making a selection on an image before creating an adjustment layer, the changes will only be applied to the selected area. Open an image and make a selection, then create a Levels adjustment. Notice how the selection appears in the layer mask thumbnail.
You can also add Styles to adjustment layers. Open an image and select a rectangular area. Create a black and white adjustment layer, so that only our selection will appear black and white.
Go to the Masks panel and click "Invert", so that our selection is now in colour and the rest of the image in black and white.
Now double click on the b/w layer to bring up the Layer Style dialogue box. Select "Stroke" from the bottom left to add a border to the layer, and choose the size of the border and its colour.
Now select "Inner Shadow" and adjust the opacity, angle, distance and size settings to your liking (the best way to adjust the 'angle' setting is actually to drag the shadow around on the image itself).
You can even move this adjustment layer, along with effects, around the photo so that it applies to different areas. Hit Cmd/Ctrl + T to use Free Transform to change the angle of the layer too.
Clipping masks are made with 2 layers, to make the image/adjustments on the top layer only visible on the area specified by the layer below it. This is great for limiting the changes of an adjustment layer to the same area as those on another layer below it.
Let's see what this means in practice. Open an image in Photoshop and make a simple selection. Create a Levels adjustment layer and increase the contrast of the image, within the selected area.
Now create a black and white adjustment layer, which will be applied to the whole image.
But we only want to apply the b/w adjustment to the same area as the Levels adjustment. So, alt-click on the boundary between the Levels and b/w adjustment layers in the layers panel.
The creates a 'clipping', linking the changes of the top layer to the area specified by the bottom layer.
Clipping masks with text
This can be used for other cool effects, like creating image filled text. Open an image, then create a new layer and fill it black (by hitting alt + backspace). Now create a text layer on top, using a font other than black. Double click the background image, and hit OK when the New Layer dialogue box appears (this makes it a layer). Drag the image to the top of the layers panel. So you should have a black layer at the bottom, then text, then an image.
Click the eye icon on the image layer, to make it invisible and see your text on a black background. Click it again to make it visible.
Now create a clipping between your image and text layers, by alt-clicking on the boundary between them.
You should now see some cool image filled text. Choose the move tool, and select the text layer, to re-position your text around the image.
So that's the end of lesson 7, an introduction to using Photoshop masks. I hope you found it useful. You now know how to create a layer mask, merge images with layer masks, use adjustment layer masks, add styles to adjustment layers and create clipping masks. These are incredibly useful techniques that will really help you with your post-processing work.
For a beginner-friendly book with step-by-step Photoshop tutorials, I recommend "Photo Nuts and Post" by Neil Creek.
Photoshop Tutorials For Beginners