I've started a drawing in an empty file with one layer (I have deleted the initial Background layer, then created a New Layer which contains the drawing).
How do I save this as tga but with transparent background? ie. so that if I put the saved .tga file over another image, only the drawing shows, without the background around it.
Many game engines still use TGA, and for some reason it still gets used in some 3D apps and video production apps.
Sadly, nobody can agree on what the fourth channel in TGA should represent: transparency, or arbitrary alpha/mattes.
At this time, the Photoshop TGA plugin still uses the first alpha channel (not transparency) for the fourth channel in TGA files. We tried to change that to transparency at one time, and got too many customer complaints and had to change it back.
So there's no way to achieve "total background transparency"?
Here's an indepth example: Some time ago someone showed me it was possible, but I forgot the way.
Essentially there were two files: Bottle.TGA and Label.TGA, each with only one layer and no selections. Both were opened in Photoshop, separately. One was a bottle, the other the bottle's label.
I dragged the label, from its file, over the bottle file. The (white) background (the PS canvas) that surrounded the label dissapeared as soon as the label entered the other file's window.
Now I had two layers. The uppermost was the label one and it had 2 icons: the label miniature and a black and white icon, and betweeen them a chain/link icon.
How was that possible?