Image Export Formats

[Midgardsormr]

The Photoshop Document format is not an export format, so I have put off detailing it. I've learned a little bit about it recently, though, so I thought I'd throw it in here.

PSD, as its name suggests, is the internal file format used by Adobe Photoshop. Because Photoshop is so widely used, PSD files can often be read by other software, although few other programs will access all of its features. This compatibility is helped along by PSD's structure, which is a modified form of TIFF. The largest difference between the two is the lack of adjustment layers in TIFF.

The related PSB (PhotoShop Big) format is intended for Photoshop documents that exceed 2 GB in file size and/or 30,000 pixels in resolution (horizontal or vertical). I believe that it also has provisions for images with 32-bit float channels, to permit High Dynamic Range (HDR) imagery. I am relatively new to HDR topics, though, so I don't know all of the details there. Anyone who does is welcome to chime in. PSB does have a limit of 300,000 x 300,000 pixels, but no file size limit that I am aware of (except that imposed by the file system, of course).