How to create video graphics with alpha channels in Photoshop

Sometimes you need to import images into non-linear editors with alpha channels. Here’s one way to make drop-shadowed video graphics with alpha channels in Photoshop.

PART A) First you have to arrange your layers properly and add drop shadow:

• If you are dealing with multiple layers, merge copies of all your layers into a single layer. (Keep the original layers intact so that you can make changes if you need to.)
• Turn the visibility off on all the layers except for the artwork layer. You want to be able to see your artowk over a light background so you can add the right amount of drop shadow.
• Add the desired drop shadow to the artwork layer (You can double click the layer to get the layer style menu)
• Turn the drop shadow into its own layer (Control click the effects layer name to get a pop-up menu. Select “create layer” from the choices)

PART B) Next you need to make a selection from your drop shadow layer and your artwork and turn it into an alpha channel.

• Create a black background layer (assuming you want a black drop shadow)
• Apple-click the name of the drop shadow layer to select it
• Hold down the shift key (to add to your selection) and click on the artwork layer. (You can add multiple layers in this manner)
• Click on the channels tab and click on the “Save selection as a channel” button. Once you do this you should see an alpha channel appear in the window.
• View the alpha to see what it looks like
• You can save a copy as a PCT file for Macintosh non-linear editors or as a TIFF for PC editors.

Making truly transparent drop shadows requires a slightly different tact. To do this start out by doing PART A, then do PART C.

PART C) In this step you will turn your selections into two alpha channels. Your drop-shadowed alpha will be transparent while your artwork alpha will be opaque. These are then combined into a single alpha channel for output as a PICT or TIF.

• Apple-click the name of the drop shadow layer to select it
• Make a new Alpha Channel from your Channels window & highlight your new Alpha Channel. (You should still have your selection at this point)
• Select “Fill” from the “Edit” menu. Fill it with white and set the opacity to be the amount of transparency you desire. (50 for half opaque etc)
• Apple-click your new alpha channel name to select your new, semi-opaque selection
• Go to your layers and, while holding the shift key, apple-click your artwork. This adds your artwork to your selection.
• Go to your channels and click on the “Save selection as a channel” button. Once you do this you should get a new alpha channel containing an opaque alpha of your artwork and a semi-opaque alpha of your shadow.
• View the new alpha channel and see what it looks like. If you are satisfied, discard the first one (Photoshop can’t create an alpha channel PCT with two alpha channels)
• You can save a copy as a PCT file for Macintosh non-linear editors or as a TIFF for PC editors.

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