[LargeFormat] Scanning B&W negs in colour

[Pam Niedermayer]

This is a little confusing. Postscript is a printing/display (ATM,
e.g., is a subset of Display Postscript) technology, not a scanning
technology. The context of Postscript in this explanation is that
since PS printers only print to 256 levels, the scanner makers don't
bother to scan more grayscale levels, since their assumption is that
you'll be scanning digital prints.

I'm not sure whether it's true or not that the scanner makers have
stopped at 256; but the article you're paraphrasing/quoting is at
least 4 years old.

Also, the scanning software used is a major driver in the process; so
you may want to investigate getting Ed Hamrick's VueScan, which comes
highly recommended by the multitudes (I haven't tried it because I've
got this Opal Ultra with Linocolor stuff), think there's a free demo
version available. His site is at:

http://www.hamrick.com/vsm.html

Pam

Clive Warren wrote:
> ...
> 
> Thanks for the URLs Guy - have popped along to one which gave some
> enlightening info.
> 
> "The current PostScript specification only allows for 254 halftone steps
> (the way a shade of grey is represented in print, 254 steps with pure white
> and pure black which makes 256 total). The extra grey shades (bit depth)
> may help to improve the scanners optical density (OD) range if implemented
> properly. This can give you better shadow detail. Unfortunately most
> moderately priced 30- and 36-bit desktop scanners implement the the
> expanded bit depth only in color, opting for a more common lookup table
> (LUT) approach to greyscale scanning."  Taken from |The Scanning FAQ
> Compiled and maintained by Jeff Bone  -
> http://www.infomedia.net/scan/The-Scan-FAQ.html
> 
> This would explain why it is better to scan in colour and manipulate
> post-scan using image editing software.
...

-- 
Pamela G. Niedermayer
Pinehill Softworks Inc.
600 W. 28th St., Suite 103
Austin, TX 78705
512-236-1677
http://www.pinehill.com