Photoshop - Selections and Masks

We have been exploring selection and channels, how these Photoshop features add so much to your creative potential. Blending these tools with masks opens up another world all its own. Masks let you combine objects and migrate objects. Your friend can be standing in the Himalayas, your product can be sitting on the President’s desk.

Masks do just that. They ‘mask’ a portion of your image which is simple enough but with Photoshop layers it is very easy to bring other things into your image. Of course as your blend these in clever ways, you create your own scenarios and this ability to create is much of the mask’s magic.

We like to set up simple exercises that focus on the basics of how to use a new tool. Once you are comfortable with how it works, you can move on to more complicated and creative applications. To apply a mask, a good playground is much like our selection models. We are going to highlight an image in a particular background, then mask, ‘hide’ the background so a different layer comes forth. You might use two images, one as your foreground object, then copy the second into the first as a layer. This masking works by exposing imagery from an otherwise hidden layer so you can think of these two images, these two layers, as your two scenarios.

For example, you might have an image with a candle on a table but your second image is an outdoor scene. When we apply our mask your highlighted object will appear in the different backdrop so you could have your pet on the patio, then apply a mask that will place him on a mountaintop.

Once you choose the two images to work with, be sure your have placed them in the same image, in the same file, but on two different layers. If you are not sure about this, simply copy your complete ‘second’ image, go back into your first, create a second layer by choosing the far right icon at the bottom of the layers panel, next to the trash can, then copy this second image on your new layer. You want this to be in the backdrop so drag the new layer under the first and the first layer will be the only one visible. Only when we apply a mask will part of your second image show through.

Now create a selection on the object that will appear in both images. I’m going to use a candle so for the remainder of this exercise, I will refer to my candle. I will apply a selection to my candle, but now I will add a layer mask from this selection by choosing the third icon from the left at the bottom of the layer panel. This option looks like an empty circle placed inside a square. When you click on this option, a layer mask is created for you using your selection boundary as the definition of your layer mask.

Once you create your mask, you will see the remainder of your image disappear. In my case, only the candle remains but I do see the image that I copied in as my second layer. This is pretty close to instant gratification! You apply a mask and instantly your image is now superimposed on another background!

With what we have learned about selections and channels, there must be a new channel at work here… and there is. If you switch to your channel tab, you will see that creating layer mask did create a new channel. This understanding of how this information is kept and saved is helpful as you get more creative with your designs and backtrack over previous ones.

Knowing this newly created ‘mask’ is indeed a channel means you can do all the things we have learned up to this point: you can load this channel as a selection to use it again, you can save this channel with a new name and you can save this channel to a different file.