Using the masking tools in Photoshop is more about showing things off than hiding them. They can be a tricky thing to master, but I will use this tutorial to show you how to use effective masking techniques in your work.
To demonstrate the tools, let’s create a space themed application icon. These complex pieces of artwork often incorporate many existing images or textures to represent the software in one single and complete icon.
Let’s start with a blank 512×512 canvas. Nice and easy? It doesn’t get much harder. Our icon is going to need some kind of background. I already have an image I want to use so I have dropped that into the document. Not great though, I think it needs some stars.
I have dropped in another image of a starry sky and set the layer mode to screen; this creates a good starting point for the space background. However, I do not want these stars to show up everywhere, some of the stars are too strong and take away from my texture behind. It’s mask time.
While ensuring the layer you wish to mask is selected, press the layer mask button at the bottom of the layers palette (it’s the third one in, the square with a circle inside). You’ll notice it has attached a strange new thumbnail to your layer. This is the masking layer and it is currently filled with white. To start pushing back those stars, take the brush tool, set hardness to 0% and brush opacity to 50%. Finally make sure the colour is set to black. Now when you start painting you will see the stars start to disappear, as if they were being erased. Cool huh? Now check that mask thumbnail – its filled with black, white and grey sploges.
Those black and grey sploges are where you have been painting. Photoshop will hide the areas under black and partially hide areas under grey (the amount of ‘hiding’ depends on the lightness of the grey.) Anything on that layer under the white areas of the mask remain visible.
When you are working with masks you can paint on the layer by clicking on the layer thumbnail, paint on the mask by clicking on the mask thumbnail, and delete a mask by selecting the mask in the palette and either dragging it to the bin or pressing backspace.
So why use the mask and not the eraser tool? Are they not both doing the same thing? To find out, set your brush colour to white and start painting on your mask again. The stars will become visible again. Masks are non-destructive. This is incredibly useful as you can keep working on them, refining them and remove them entirely if you decide you don’t like them without losing any important information. Now, onwards with the icon!
I have dragged on the main feature in this icon: the spaceship. But I feel it needs something to make it stand out. There is nothing like rays of glowing light to highlight a vector spaceship! Use the gradient tool to put a circular white glow onto a new layer.
Hm… its not quite right. I designed a light rays shape in illustrator and copied and pasted it into photoshop. Now it is positioned I would love for that glow to only occupy the shape. To do that we need another mask.
It would be painfully slow to paint the shape of that light rays layer ourselves. Can we get photoshop to do it for us? Yes! Cmd/Ctrl click the rays of light thumbnail and photoshop will generate a selection based on the layer. Then click the glow layer and press the mask button and photoshop automatically creates a mask from the selection. To see the effect hide the rays of light shape.
Awesome! That looks much better. Now lets use those same techniques to turn this picture into an icon. Group all of the layers by selecting the top one in the palette and shift selecting the last one (Note: if you have a background layer you will need to convert it to a standard layer by double clicking it and pressing enter) then press Cmd/Ctrl + G to group those layers. Next take the rounded rectangle tool and draw out a square over everything.
We are going to create a mask on the group so everything inside is masked. Cmd/Ctrl click the rectangle thumbnail to create a selection, click on the group in the layers palette and then click the mask button at the bottom and ta-dah! A white square? You’ll also need to hide the white rectangle as it is still sitting above the group.
There is your icon, almost complete. I am going to show you how to create a shadow below the icon to make it look as if it were hovering. You could easily paint it in yourself, but knowing how to do it with speed and accuracy with a mask is a useful skill. Create a new layer and place it underneath the group, then fill it with black. Next, take the ellipse tool and draw out a shadow so you have something that looks like this:
Know whats coming next? You guessed it! Cmd/Ctrl click the ellipse thumbnail to create a selection from the layer. Then select the layer of black and press the create mask button and… oh. That doesn’t look very much like a shadow…
The mask is solid because the shape has a solid outline. But here is a trick that could come in handy. Let’s take it back a step. Use Cmd/Ctrl + z or delete the mask on the black layer. Create the ellipse selection again by Cmd/Ctrl clicking the thumbnail but this time go to the Select menu -> Modify and Feather (or Shift + F6 for the shortcut savvy) Set the feathering to about 15px and then press ok. You may be asking what that did. To find out, select the layer of black and now press the create mask button.
Feathering a selection will soften up the edges. Using this in combination with masks can help you to create a shadow without having to paint one in by hand.
There you have the skill needed to implement the basic Photoshop mask. Experiment and it will really help you speed up your workflow.
