In "Reality and Digital Pictures [1]," (2005-12-12) and "Editing Photographs for the Perfectionist [2]," (2004-9-27), I recommended some plug-ins by Asiva [3], particularly Shift+Gain. A few months ago they became unavailable, but the developer is bringing them out again under a new corporate entity and is promising to make them available in universal binary form.

[1]: http://db.tidbits.com/article/8365
[2]: http://db.tidbits.com/article/7832
[3]: http://www.asiva.com/