For example, lets say I open a .png with transparency. Now, while the image has tranparency, it doesn't have an explicit alpha channel (like a .tga for example). My current (likely inefficient) method is thus:
1) Open the source.
2) Dupe the transparent layer.
3) Lock the transparent pixels on the duplicate.
4) Color the pixels black with the pen tool.
5) Add a drop shadow (one of the parameters for my project)
6) Add a backgound layer under the copied layer
7) Paintbucket the background white
Merge the copy and it's background to create the future content for the alpha channel
9) Inverse the merged layer
10) Copy the layer to a new alpha channel
There MUST be a simpler way to do this - any help would be greatly appreciated. I am new to photoshop, so be kind!
Thanks in advance,
Jordan