Photoshop: Alpha Channels and Layers Tutorial

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Selection Alpha Channels:
Download the orange basket image to your desktop.
Uncompress the file.

In Photoshop:
Choose File->Open
Choose the desktop
Click the file Francisco_de_Zurbaran.jpg
 
Use the Magnifying Glass to zoom in on the  image. PSmag.gif
 (The option key with the Magnifying Glass zooms out.)

Choose Select->Color Range...
         Fuzziness: 90
Click on the white background.

Choose Select->Modify->Expand
    
Input Expand by: 1 pixel
This will clean up the edge pixels.

 Choose Select->Inverse, to select the oranges instead of the background.

Save the selection to an alpha channel.
      Choose Select->Save Selection
      Click OK

Choose Windows->Show Channels 
Click the fourth channel to bring up the alpha channel, you may want  to modify it.
Click the first RGB channel to bring you back to the main image.
You may save as many alpha selection channels as you like.

Choose Select None      (This deselects the channel.)

Load  the alpha selection channel.
Choose Select->Load Selection
                    Choose Alpha 1
 
 
PSchannels.gif
 
Layers:
Choose Edit->Copy     (This saves the selected area to a temporary buffer.)

Choose Edit->Paste     (Paste the selection into a new layer.)

Choose Windows->Show Layers  (Layers is a tab under the Channels tab.)

You can select separate layers to modify.
Notice the top layer has transparency or alpha, this is another alpha channel.

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Select the Background Layer from the Layers window.
Choose Select->All
Hit the Delete Key on the keyboard.
Notice the image fills with the background color in the Tools window.

Select a new color, please notice how this effects the feeling or your perception of the image.

Click the small arrow on the upper right of the Layers window to bring up the menu
Choose Flatten image     This will merge the two layers.
You lose the alpha information from the layer.
You still have the alpha information in the Channels window.
If you do not understand the difference ask!

robot.jpg

Francisco de Zurbaran, 1598 - 1664
cut-out from Lemons, Oranges and Rose
download me

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robotclouds.jpg

This is what you should end up with. Choose your own color.