I frequently need to create logos and other graphics with a transparent background to use on television broadcasts.
I always have created these as Targa files. Using Photoshop 7, I would accomplish this the following manner: 1.
Command-click on the layer to select the graphic <2.> Save the selection as a channel <3.> Make this channel (the new alpha) visible in the Channels pallette 4. Save as 32 bit Targa file.
In Photoshop CS2,:
- I cannot use a keystroke/mouse combination to select a layer as in PS7
- I then must go to the Select drop-down menu and first choose to "load selection" and then "save selection"
When you click on the layer, make sure you're clicking on the layer thumbnail, and not the layer name. The Layers palette works a little differently in CS2 (you can now shift-select multiple layers, something I've wanted for years), so it makes a difference where you click.
In general, the steps you're using to create an alpha channel may not be necessary. The PSD and TIFF formats carry transparency (alpha) information without having to create an explicit alpha channel. If you don't have a background layer (just the transparency checkerboard showing) and import the PSD into After Effects, AE will catch what is supposed to be transparent. This will vary depending on the broadcast application you're using, of couse, but TIFF and PSD are pretty standard these days, and most applications know how to read them properly.