Alpha channel mask (alpha channel)

An “Alpha Channel” is a grayscale image, you use Alpha Channels to make selections and save. This can be very useful when you’ve spent several hours making a selection. Save them as Alpha Channel, and you can use them later. Images with Alpha Channels can only be saved as PSD, TIFF, TGA and PNG-24.

In the next example I will show you how to save a selection as an Alpha Channel.
Actually I’m going to make three selections for the Alpha Channels in this example.
Okay, we open a photo in Photoshop.
I have chosen a photo of a boy who is enjoying his vacation.
We select the lenses of the sunglasses of the little ones with the “Quick Selection” Tool.
This does not have to be the “Quick Selection” Tool, but I think this is the easiest tool for this action.

The first option to save the selection, is to choose “Select” – “Save selection” in the menu bar.
In the dialog that appears, we enter the location, in the top box, where we want to save selection as Alpha Channel (this only applies when multiple files are opened).
In the second box, choose the Channel. For us, this is “New” of course, because we have no other Alpha Channels.
And in the third section, we give an appropriate name for our
Alpha Channel, eg glasses.
Click OK.

This adds the channel to our Channel palette.
You see, the black part is not selected, the white is selected.
Open the newly created channel by selecting in the “channel palette”. You can see that the selection still exists. We currently do not have this anymore, so we “de-select” all by clicking “Select” – “Deselect” in the menu bar.
We click on the RGB layer to return to our image.

Now the second option to save the selection.
We select the left glass of sunglasses with the “Quick Selection” Tool and we are adding even more selection to it, eg with the “rectangle” tool.

Click the “Save selection as channel” at the bottom of the “Channel” palette.
The new channel named Alpha 1 will be automatically added to the channel palette.
We double-click the name and give a more suitable name, eg left glass.

Tip: If you hold the Alt-key on your keyboard pressed when you click the “Save selection as channel” button, the dialog box opens where you can enter a name for the Alpha Channel.

OK, now for the third option to save selection.
We make another selection, but the right glass of the goggles.
We click the button “Create new channel” at the bottom of the Channel palette. (Hold the Alt key(Option on Mac) on your keyboard when you click this if you want to give a name to this channel immediately).
This gives us the representation of the last created channel again.
You only see the selection on a black background, so we still have to paint this selection with white.
First make the foreground color in the toolbox white and the black as the background color.
The shortcut for this is the D button on your keyboard.
Then click on the buttons Alt (Option for Mac)+ Backspace on your keyboard.
This gives white color to our selection.

Now we have to save the Alpha Channels. This may not be a “.Jpg” photo as above, we must save it as PSD or TIFF file.

Click on “File” – “Save as” … in the menu bar, select one from PSD or TIFF format in the box and most importantly, check the box “Alpha Channels” on.
Click “Save” button when you’re done.
If you have chosen the TIFF format, then you get the TIFF Options dialog box.
The only thing you change is in the upper section, “Image Compression”, check LZW rather than NONE. This is a very good for our photo compression.

We now have our three Alpha Channels created and saved.
In the next lesson we will also do something with it.

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