TGA puzzle

[terrypin]

Can someone help me get my head around the way that various programs open TGA files please.

Starting simply, why does my test file open differently in PSP 8 versu 2018?

[LeviFiction]

So, TGA files are able to contain a single alpha channel. The image has to be saved 24/32 bit format uncompressed for this channel to be maintained.

Well, with some very limited testing it looks like PSP8 does not load this channel in my default you either have to load a selection or mask from alpha channel to see the result that you see in 2018. In PSP2018 it seems to load in the alpha channel as part of the image deleting anything that isn't inside the area indicated by the alpha channel. I'm unsure which version this started with. PSP8 - PSPPX2 all work the same opening the full image without applying the alpha channel.

A similar problem exists with TIFF files that have an alpha channel. PSP merges the alpha channel with the image.

[terrypin]

Thanks Levi, appreciate that fast and characteristically helpful reply.

I'm pursuing a likely bug in my video editor, Magix Movie Edit Pro Premium (MEPP), which uses that file to display a caption. But googling about TGA and opening that specific file in both my PSP versions in the hope of insight has only confused me further!

If anyone is curious, the nature of the strange behaviour I'm seeing in MEPP is that the caption effect is disappearing from some (and later all) of the multiple captions in which it was used. The sort of behaviour I might expect if the TGA's alpha channel was somehow getting switched off when the file was used a few times! I wonder if there's any parallel in PSP that might indicate that the file is 'unstable'?

Should anyone want to play with it and let me have any feedback, I've uploaded it here:
https://www.dropbox.com/s/2xbyj4qlww16f ... .tga?raw=1