Photoshop has many tools that allow you to select a part of an image, known as a selection. A selection allows you to modify only the selected part of an image, such as performing a colour correction, transforming (moving, scaling, rotating, skewing etc), masking and so much more. Selections can be saved so they can be reused, so you don’t have to remake them if you need them again.
First let’s take a look at a selection. The dashed line below, or marching ants as it is often referred to as, indicates that the tomato is selected.
The above selection was made with the Quick Selection Tool, but there are many tools for selecting in Photoshop.
To save the selection, go to Select > Save Selection… The Save Selection panel will appear. But you could always right-click on the selection too and choose Save Selection.
Type in a name. I have chosen the name Tomato, as can be seen above. Then click the OK button.
The saved selection can be seen in the Channels panel. The selected area is represented as white, while the unselected area is represented as black. By saving the selection, you have created an alpha channel.
If the selection became deselected, the selection can always be reloaded by going to Select > Load Selection. The Tomato saved selection can be selected from the Channel drop-down menu as shown below. A document can contain multiple saved selections/alpha channels.
So next time you have created a selection, especially a complicated selection, think about saving it because you never know when you will need it again. Always try and save your document as a .psd file – a Photoshop document file. That will ensure that your selection is saved with the document – other formats may lose the saved selection. There are also many software application that can import .psd files and use the Alpha Channels (saved selections) for masks, text wraps and so much more.