Re: filmscanners: PSP and 48-bit color question

["Rob Geraghty" <harper@wordweb.com>]

> I just tried loading a .tiff file that was scanned in Vuescan at
> 48-bits, and I get the following message:
> "A predictor of 2 is only supported for LZW compression on 8 and 24
> bit images."
> I guess I can go back and scan at 24-bit, but what should I know about
> this?

Save the file from Vuescan as an uncompressed 24 bit TIFF, or even a 48bit
TIFF, but it must be uncompressed.  PSP doesn't work with 48bit images and
will convert the picture to 24bit after opening it.  Since it is a 24bit
editor, JASC didn't implement the decoding of 48bit LZW images.  I raised
the issue with JASC as a feature request about a year ago.

Recently I've been using the 16 bit capability of Picture Window Pro to do a
levels adjustment and conversion to 24bits.  PWP allows me to adjust the
levels in HSL rather than RGB, and this results in less colour shifts.
After conversion to 24bit I prefer to use PSP for most editing such as
cleaning up scratches or spots, conversion to web dimensions, saving as
jpeg, and printing.  PSP doesn't embed profiles or previews in images - a
disadvantage if you need the feature, but if you're making web images it
means they're more compact.

Rob