How to Duplicate and Delete Channels in Photoshop CS6
Duplicating channels in Photoshop CS6 is something you may do quite often. And deleting channels isn’t just for neat freaks: Channels take up a lot of memory, so getting rid of the ones you no longer need is always good.
Here are some instances when duplicating channels is a good idea:
When you want to create a channel mask: First, you find a suitable channel and then make a duplicate. You can use channel masks to select difficult elements involving fine details, such as hair, fur, smoke, and so on.
When you want to make a backup copy of the channel before doing some editing: Having a backup, just to be on the safe side, is always a good idea. For example, you may want to apply an Unsharp Mask filter to one or two channels to improve the focus of the image.
To insert a copy of an alpha channel into another image: For example, maybe you spent an hour creating elaborate alpha channels for shadows and highlights on a product photographed in flat lighting.
You may have 12 products, all the same shape but different colors, that you need to apply those highlights and shadows to. Instead of re-creating the wheel each time, you could simply duplicate the alpha channels into each file.
How to duplicate channels in Photoshop CS6
To duplicate a channel, follow these short steps:
Select your desired channel in the Channels panel.
Select Duplicate Channel from the panel menu.
The Duplicate Channel dialog box appears.
In the Duplicate section, in the As field, name the channel.
You can also drag the channel to the New Channel icon at the bottom of the panel. If you do this, Photoshop provides a default name and bypasses Steps 3 through 6.
You can also duplicate a channel to another image by dragging the channel. Open your destination image and drag the desired channel from your current image into the destination image window. The duplicated channel appears in the Channels panel.
In the Destination section, select a file from the Document drop-down menu (pop-up menu on the Mac).
Or choose New to create a new image.
You can choose your current image or any open image with the same pixel dimensions as your current image.
If you choose New, Photoshop creates a new image that has a single channel. Provide a name for the file.
Select Invert if you want to reverse the selected and unselected areas of the duplicate channel.
You use the Invert option primarily when you duplicate an existing alpha channel.
The dialog box closes. Your duplicate channel appears in the Channels panel.
How to replace one channel over another
To replace the contents of one channel with another, you can use the copy-and-paste method. In your current image, select your desired channel in the Channels panel. Choose Select→All and then Edit→Copy. Select the channel in the destination image that you want to replace and choose Edit→Paste. The pasted content of the channel replaces the original content.
How to delete unwanted channels in Photoshop CS6
To delete an unwanted channel — something you definitely want to do because channels can eat up a lot of space — select the channel in the Channels panel and do one of the following:
Drag the channel to the trash icon at the bottom of the panel.
Select Delete Channel from the panel menu.
Click the trash icon and then click Yes in the dialog box.
Alt-click (Option-click on the Mac) the trash can icon.