What is a Channel?

A “Channel”, is a grayscale, which stores various information of our images.
To open the “Channel palette”, click on “Window” – “Channels” in the menu bar.
You can change between three different types of channels.
The first type is “Channels, Information of Color,” which are automatically created when you open a new image.

The “Color mode” (color mode) used by the image determines the number of color channels.
For example, in RGB Color Mode you have four channels.
A Red (Red), a Green (Green), a Blue (Blue) and a composition of the previous three, RGB.

Another type is the Alpha Channel.
You create an Alpha Channel to create a grayscale mask that allows us to isolate, select or protect certain parts of our image.
Alpha Channels are only tracked when we store the image as a PSD, PDF, PICT, Pixar, TIFF, or RAW.

And the third is the Spot Channel.
We use Spot Color Channels to specify Specific Channels and use when printing spot color inks. But this is beyond this course.

Our image can contain a maximum of 24 channels.
We use the “Channel palette” to create and manage channels.
In the “Channel palette”, the first thing we see is the composite color mode (RGB), then Red, Green and Blue, only then will be the enclosed channels.
We use the “eye icon” on the left side of the channel to show or hide the channel.
In alpha channels, selected pixels are displayed in white, non-selected pixels in the black and semi-transparent pixels in gray.

We can use the tools in the Toolbox to edit the different channels.
Remember this: when you use eg the Paint Tool with the color white in a channel, this is the color of the channel with an intent of 100% view.
When you use black, this will be the color of the channel with an intention of 0% display, in other words, no display at all.
When you color with a gray value, the color of the channel is for semi-transparent display. The lighter the gray, the higher the transparency.

As you can see in the picture above, I have drawn one white, one black and one gray line in the green channel.
Where I have drawn white, the extra green appears.
Where I’ve drawn black, green is no longer displayed.
And where I’ve drawn gray, the green is displayed with a transparent value.

I hope you’re not too bad, because I would not know how else to explain it.

To remove a channel, drag it to the trash can down the “Channel palette”, the same way you would remove a layer.

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