The Plugin Site

File format or import plugins let you open images that are not natively supported by Photoshop. There are several of these plugins around, but I don't think there is one that supports special tif formats.

You can write such plugins with the Photoshop SDK, which is available on all Photoshop CDs up to Version 6. The Photoshop 7 and CS SDK don't inlcude the specifications for file format plugins anymore, so you need a special permission from Adobe to get them.

An alternative is to use the Photoshop SDK for Delphi from www.centaurix.com which lets you create such plugins, too.

HaraldHeim wrote: The Photoshop 7 and CS SDK don't inlcude the specifications for file format plugins anymore, so you need a special permission from Adobe to get them.

File Format plugins haven't changed fundamentally since version 3.0, so this is a pure smokescreen from Adobe. You can use any version SDK to make File Format (or other) plugins for PS7 and PS CS - on any platform.

It can be expected that a future (post-CS) version of Photoshop will introduce a new API for plugins, but Adobe would be insane to not support the older API for the existing base of products by third parties.

bill87 wrote:Are there plugins available that would allow Photoshop to open graphics formats it does not natively support?

Is it possible to write such plugins, or do plugins only "engage" after a file is alreagy opened?

Particularly I am looking for a way to open TIFFs with CCITT Level 4 compression directly into Photoshop CS.

To answer your questions in order: Yes; yes; no; and there is a way to use G4 TIFFs with Photoshop. You can use the free tools at http://libtiff.org/ (in particular, tiffcp) to recompress them with a different compression method (or none) and then open them in Photoshop. Naturally this can be batched or scripted if you desire.