How To Create an Alpha Channel in Shake

An alpha channel is designed to create depth in computer graphics, and using Apple Shake to create one is a relatively straightforward process. While creating an alpha channel in Shake does require several steps, it's not hard to do, and this simple how-to guide will show you everything you need to know.

What You Will Need

  • Video File to edit
  • Apple Shake installed on a computer

Step 1: Import Video into Shake

After you have opened Apple shake, you can import the video footage into the program by simply dragging the file from your folder onto the viewer in Shake. Alternatively, you can import the file by going to Image/File In.

Step 2: Change Bit Depth of Video

Before you can create the alpha channel, you need to add some information to the video file footage. Therefore, look on the menu tab and go to the 'Other' link. On the 'Other' menu list, there is a node called 'Bytes'. You can apply the 'Bytes' node by clicking on it once.

Once you created the 'Bytes' node, a new node will be presented to you on your screen. Click on the small square on the right-hand side of the new node in order to load the parameters into the window at the bottom right of your screen. Once the parameters screen is loaded, change the 'outBytes' option to 'float'. This does not affect that quality of the image; however, it does allow you to enable certain effects and grades of a higher bit-depth.

Step 3: Select and Adjust Keylight Parameters

Next, select the 'Bytes' node in your viewer. Go to the 'Key' tab your menu bar, and then choose the '[CFC] Keylight' option. Once you select the Keylight option, you will see that the option has four inputs available. You can drag your mouse over each input type to put an explanation for their use at the very bottom of your computer screen. You can adjust the inputs as you see fit to manipulate the color key in your image.

In order to create your alpha channel, you'll need to choose the color that you want to remove from the footage. On the Keylight parameters page, you'll notice a 'screen colors' option. Click on the screen color button to load the color palette viewer on your screen. To remove a certain color from the footage, drag the mouse over the area that has the color you want to remove. When you drag the mouse over that particular color, it will be replaced by black.

Step 4: Apply Keylight

Click on the File/Save option to apply the Keylight or click on the submit button. You have now completed the creation of an alpha channel and Apple shake.

Step 5: View New Alpha Channel

In order to view the new Alpha Channel, position your mouse over the image and then press 'a' on your keyboard. By pressing the 'a' key on your keyboard, you'll be shown the alpha channel. You can then press the 'c' key to return to the color version of the image.

Step 6: Adjust Alpha Channel as Needed

If you need to make adjustments to the alpha channel, you can open up the 'KeyLight' node again and use the sliders or other color palette options to customize the newly created alpha channel.

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