Digital BW, The Print

this is exactly the point of doing some b&w negs scan tests in RGB- to investigate the 
possibility of a superior channel, or channel combination as you describe. Once 
determined, if you have the channel option for mono as you describe (Silverfast also has it, 
I've seen it elsewhere as well) there is no reason to make the larger RGB scans from B&W in 
the future.
If you have a clearly desirable channel, and no such option in the software, there is no 
choice but to scan in RGB then toss out the other channels once in Photoshop.
It is quite possible some scanners perform well in all channels, and a more typical RGB to 
Gray conversion in the scanner software or elsewhere will be fine, or desaturate, or LAB, or 
whatever your prefer.
Another reason to investigate individual channels to optimize workflow is for staining 
developer users.

Some software has problematic LUTs for B&W negs, that never give you access to all the 
info on some or all negs. This would be another reason to use an alternative procedure- 
scan as a transperency to open up the capture range, and invert in PS later. Or, with 
Vuescan use the raw file, or Silverfast's HDR.
Tyler


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Peter De Smidt <pdesmidt@...> 
wrote:
>
> >  There is no advantage to scanning a b&w neg in RGB as the three
> > channels (and hence the three times larger file) will be identical.
> Vuescan allows you to make a greyscale file from any of the color 
> channels.  I tried the default way, and then each of the various color 
> channels.  The green channel with my Canon 9950F gave the most detail 
> with the least noise for scanning BW silver negatives.  As such, I set 
> Vuescan to make the grey 16 bit image from the green channel. This does 
> not require having an RGB image, with the resultant huge file size. It's 
> easy to test these things. Try each way. Make sure to label the file 
> with an appropriate name.  Open them in Photoshop and compare.
>