>I have been using Adobe Photoshop 3.0. for the processing of my
>confocal/epifluorescence/TEM/SEM images. Does anybody know what extras the
>updated version (Photoshop 4.0) offers? Is it worth purchasing for someone
>who does "strictly scientific" image processing ( I have no doubt that the
>new version offers  lot more for "digital artists"). Thanks for your input.

Three points for scientists:

1: Batch processing
        Now you can let Photoshop learn certain routine processes so
        that it can perform them automatically. Although it was possible
        to do this using a third-party plug in with Photoshop 3, Adobe's
        integration of this feature is more intuitive and simpler to use.
        If you want to raise the contrast -> unsharp-mask of a 100-picture
        stack, this is a real boon.

2: Non-distructive contrast/tone/colour adjustment
        Using the new "adjustment layer" you can modify the contrast,
        tone and colours without changing the original data. Thus, you can
        try different settings much more easily.

3: More format for web pictures
        Now you have more options to save pictures with formats commonly
        used for web publications.

Kei