What are all those file formats for?

I've used Photoshop for ages (since version 3), and I habitually only save files as TIFF, JPEG and PSD, depending on the situation.

Occasionally I've saved GIFs, Bitmaps and EPSs.

I'm bemused by all the other file formats available in Photoshop. What the heck is a Targa file? Scitex CT?? PCX?

I'm interested to hear if anybody knows what these other strange file formats are for, and if they use them.

Some of them might be for backwards compatibility. Once somebody introduces a format that gets even a little popular you are stuck with it FOREVER.

Yes, I guess that's true. I love the "backward compatibility" of your signature, by the way ...

TGA (TARGA) is for movie stuff, used to be used in 3D (still is in some cases) for holding 32bit information (includes an alpha channel for transparancy)

PNG is a webformat similar to GIF, but GIF is more limited in its transparancy to PNG, PNG you can have full 0-100% transparancy, where with GIF you either have 0 or 100% no inbetween

Scitex CT, is what some older drum scanners still use to produce their files, its effectively CMYK scan straight from the scanner instead of the RGB you get with home scanning units. u used to get Scitex Workstations as well that used the same format

PCX is a rgb format (Windows Paint) supports 1, 8 and 24bit RGB not CMYK

Great info - thanks!

There's so many useful formats out there that Photoshop doesn't even try to have (comparably) many in the 'save as' dialog anymore.

wiki link to file formats