Digital BW, The Print

Austin,

Two non-technical points.  First, scanning in B&W mode using my Nikon 
Coolscan 2000 produces awful images -- flat and difficult to 
correct.  Using rgb turns on the Nikon firmware and I get a much 
better result. Second, I do find that I generally see a significant 
difference across channels when converting to b&W.  

Steve

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" 
<darkroom@i...> wrote:
> Steve,
> 
> The data may be "clear", but really doesn't give you much 
information as to
> what it really means as related to the actual image.
> 
> If you look at the histograms, as I've suggested, of an RGB scanned 
B&W
> image, you will see, what may appear to you, as small differences.  
Then,
> take a look at the actual image, and thumb through the individual 
channels,
> and you'll see a significant difference.  Point is, it's hard to 
quantify
> the actual differences in an image using the histogram...it merely 
shows
> there really are differences, but gives most people no real idea 
what the
> visual impact of those differences may be.  Sometimes it's clear, 
other
> times, not so.
> 
> I think the original issue is, as I read why Stan did this in the 
first
> place, is to determine if his scanners B&W is better/worse than 
doing a scan
> in RGB and converting in PS.  I can't draw any conclusion to that 
question,
> as the data for the scanners B&W scan wasn't presented (do you 
happen to
> have this, Stan?) along with the actual RGB data, and the RGB data 
all by it
> self isn't enough.
> 
> Whether any scanner's B&W mode will give you equal results to RGB 
mode is
> really scanner dependant, as every scanner will do this 
differently.  Almost
> all scanners scan B&W in RGB anyway, and then convert based on 
some "canned"
> mix of the three channels.
> 
> Austin
> 
> 
> >
> > Stan's data seem clear, but all I can say is that when I scan B&W
> > film as rgb, for some negatives, using the channel mixer to 
convert
> > to grayscale makes a big difference.
> >
> > Steve
> >
> >
> > --- In DigitalBlackandWhiteThePrint@y..., "Shire,Stanley"
> > <sshire@c...> wrote:
> > > Austin:
> > > That was the first thing that I did (look at the channels in the
> > histo display)
> > > tiny, tiny differences.
> > >   ----- Original Message -----
> > >   From: Austin Franklin
> > >   To: DigitalBlackandWhiteThePrint@y...
> > >   Sent: Tuesday, December 03, 2002 1:51 PM
> > >   Subject: RE: [Digital BW] Re: Convert to B&W plugins
> > >
> > >
> > >   Stan,
> > >
> > >   You can just scan the B&W negative, in RGB, and bring it into 
PS
> > and compare
> > >   the three channels.  You can compare RGB using the histogram, 
as
> > well as
> > >   compare them visually by hitting <ctl> ~, 1, 2 and 3...for All
> > Channels,
> > >   Red, Green, Blue...  Depending on the image, you will see
> > anywhere from
> > >   small tonal differences, to quite noticeable tonal 
differences in
> > the
> > >   different channels.
> > >
> > >   Regards,
> > >
> > >   Austin
> > >
> > >
> > >   > -----Original Message-----
> > >   > From: Shire,Stanley [mailto:sshire@c...]
> > >   > Sent: Tuesday, December 03, 2002 1:21 PM
> > >   > To: DigitalBlackandWhiteThePrint@y...
> > >   > Subject: Re: [Digital BW] Re: Convert to B&W plugins
> > >   >
> > >   >
> > >   > BW neg scans in color neg mode
> > >   >
> > >   > Quick on-the-fly-between-classes test results
> > >   >
> > >   > 35mm tmax 100 neg
> > >   > Tmax developer
> > >   >
> > >   > The scans were made on an Imacon 848 and a Coolscan 1000 (I
> > >   > figured that the greatest differences would show with these 
two)
> > >   >
> > >   > Both scanners set to scan at 8 bit, color neg mode.
> > >   > Scan sizes were matched as closely as possible to 25mb
> > >   >
> > >   > 4 Markers placed in the same areas on each file. Tried to 
place
> > >   > them in areas of differing densities.
> > >   >
> > >   > Imacon 848 scan
> > >   > Marker    R    G    B
> > >   > 1            22    22    22
> > >   > 2            255    255    255
> > >   > 3            240    234    234
> > >   > 4            166    165    159
> > >   >
> > >   >
> > >   > Nikon Coolscan 1000
> > >   >
> > >   > Marker    R        G        B
> > >   > 1            5        5        4
> > >   > 2            255    255    255
> > >   > 3            206    199    186
> > >   > 4            174    171    166
> > >   >
> > >   > Did not correct for density differences between the scans 
as I
> > >   > wanted make no changes to the raw data as it came from the
> > scanners.
> > >   >
> > >   >
> > >   > Interpret this data as you will. My conclusion is that yes,
> > there
> > >   > are slight differences with red being higher in density than
> > >   > green and blue being ther lowest density.
> > >   >
> > >   > The similar density differences between the two scans might
> > >   > indicate a slight warm color in the film base.
> > >   >
> > >   > Big conclusion (YMMV): Very minimal difference between 
scanning
> > >   > in RGB and GS modes.
> > >   > Very minor tonal changes when converting with the 
ConvertToBW
> > Pro
> > >   > plugin. Not enough (if I were shooting a lot of BW film) to 
make
> > >   > me go with a file that's 3x larger.
> > >   >
> > >   > Any thoughts appreciated.