Digital BW, The Print

Roy,

> I don't buy into Austin's argument.
> If you scan with white light
> passing thru the film and illuminating the CCD you have the
> artifacts, fuzziness, blooming whatever of the entire visible
> spectrum all added together.

The neutral density filter reduces the entire spectrum to an even level.
There is no bloom and smear with the ND filter, and the response is uniform
and not peaky, as it is with blue and green.

> You have the worst case.

I disagree.  You have a best case, as the spectrum is now even.  It's easy
to see that the scans come out superior using the ND filter to scanning with
RGB, this isn't arguable.  Comparing individual channels, the green is
typically the closest, and sometimes the blue, but the ND scan is sharper,
and has better tonality.

> If
> there are some frequencies (color) that have a better response
> you won't take advantage of it.

Why do you believe you want to do that?

> On the other hand if you scan
> in RGB you at least have the possibility of picking which
> third of the visible spectrum gives best results.  And even if
> you just average the three values you ought to get better
> results than just one value from a white light scan  -- like a
> builtin multi-pass scan.

Well, it doesn't work that way.  Why don't you simply take a look at a scan
of a B&W negative done in RGB and thumb through the channels as I suggested
in PS.  You will clearly see that the red channel is the fuzziest.  This is
just a very well known issue with CCD sensors.

Austin