Alex Nichols, Academic Technology Coordinator, Department of Art and Art History, Michigan State University, Michigan State University shares some more wisdom about RAW files that he addressed on the VRA list serve.

What to save when capturing images in a RAW format.

Here's what's happening when you save NEFs [Nikon's RAW file] in Capture after editing them:

Capture is actually saving notes about what adjustments you made to the file, and those notes are applied whenever you open the file again in Capture (but the raw file isn't actually demosaiced until you save it as something else -- the adjusted image you see on screen is just a preview). I believe the changes are permanently applied to a JPEG preview image embedded in the raw file, but I'm not sure about this.

What happens when you open the adjusted and saved NEF in Photoshop? Photoshop opens the image successfully, and the adjustments you made are intact, but Photoshop is no longer treating it as a raw file (the Adobe Camera Raw plugin never launches and you no longer have the opportunity to adjust the white balance, exposure, or other raw-specific settings. Is Adobe actually opening the embedded preview image, not the raw data? Again, I'm not sure). If you further edit the image in Photoshop at this point, you can't save as a NEF anymore -- you must choose a conventional format such as tiff.

What this means: If you make your adjustments to a NEF in Capture and then save it as a NEF, you actually have a more flexible file than if you'd saved it as a tiff -- all your adjustments are saved, plus if you decide to tweak them in the future, your adjustments will be made to the original raw data rather than a demosaiced derivative, and no matter how aggressively you edit the file, you can always restore the image to exactly what it was when originally captured.

BUT: What if the Nikon Capture software is no longer available or supported? You'll still be able to open your file (as edited) in Photoshop, but you'll no longer have access to the raw data.

Not so bad, but here's the really big problem with raw files as archives: almost every single camera has it's own proprietary raw format. I don't just mean Nikon has NEF and Canon has CR2 and Pentax has PEF, etc... I mean even the Nikon D200's NEF files are a slightly different format from the Nikon D70's NEF files! Because of this, every single camera must be individually supported by a given raw converter.

Whenever a new camera model comes out, all the raw software developers scramble to support (reverse engineer) the new raw files it will produce. This has been going on for several years now, and the number of different raw files (cameras) a converter must support in order to be comprehensive, is getting longer and longer and longer. How long before raw converters start dropping support for older cameras? Its already started happening -- I have raw files from an old Kodak DSLR (circa 1999) that don't open properly in any program besides the circa 1999 software that came with the camera (the files will open in Photoshop CS2, but the raw plugin won't launch and the colors are way off).

So: will Photoshop still open your Nikon D70 NEF (properly) in 7 years? Longer? Think of the hundreds of newer cameras (and with them hundreds of newer file formats) that will be of more concern to software developers at that point. Maybe everything will be fine -- the industry will come to some agreement about how to end this cycle -- but TIFFs are a much safer bet.

To move on to your other questions:

- Don't archive unedited raw files. See above reasons, plus: why would you ever want to edit it over again? (I can think of plenty of reasons in conventional photography, but not in the typical visual-resources-book-on-a-copystand scenario).

- Don't do two captures (one raw and one jpeg). If you really want this, many cameras will optionally save one capture as two files in two formats at the same time (the D70 won't, but the D200 will). Ideally, though, you should shoot one raw capture, edit it, save it as a tiff (for archive purposes) and then make all the jpeg derivatives you want.