[filmscanners] RE: keeping the 16bit scans

["Paul D. DeRocco" <pderocco@ix.netcom.com>]

> From: Ed Verkaik
>
> I've been scanning slides on the 4000ED, correcting, then saving the
> 16bit files as my masters. It's beginning to get crowded on my h.d.  My
> reasoning for keeping 16bit rather than 8bit was because I figured if I
> had to do a little more adjusting of curves, etc. then the files would
> handle it better. Am I right?  What's the difference in likely outcome
> (quality) if I did further (minor) edits on a 16bit/110mb instead of an
> 8bit/55mb file?  Rescanning of these would require up to an hour each of
> spotting because they're older Kodachromes so it comes down to storage
> space vs risks on quality.

I suggest you do some rigorous testing, to find out just how much you
actually lose by going to eight bits. My experience is that the extra bits
don't contain any useful information unless the image needs some _major_
curve tweaking. (On the other hand, if you scan B&W negs, you may find that
them more finicky than color.)

I recently purchased LuraWave's JPEG2000 plug-in for Photoshop. It does a
better job of compression than JPEG, both because it produces smaller files
before the compression artifacts become visible, and because it can handle
16bpc files. I find that I can get 5x to 10x compression on 16bpc TIFF
files, and not see any difference, even when blown way up. (By the way, stay
away from Adobe's new JPEG2000 plug-in--it's much slower.)

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com

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