On Tue, Apr 01, 2003 at 05:40:04PM -0800, Peter Klein wrote:
> I love CN Black and White film. It has a beautiful look and tonal range,
> and it scans well. But there's one problem. Take a look at the following
> picture, a crop of a larger scan, reduced 50%. It's a picture a friend
> took of me with strong sidelight, on Kodak Portra 400 B&W. It's 138K, no
> adjustments besides the size and conversion to Jpeg.
>
>
>
> See how the shadow side of my face is all speckled? Instead of fading to
> black, the scan fades to grit. I used to think that this problem was just
> grain aliasing with my 2700 dpi Nikon LS-2000 scanner. But this shot was
> scanned with my friend's 4000 dpi Poloroid (the one that takes both 35mm
> and 120 film).
>
> I've been plagued with these grungy shadows whenever I use CN film in
> available-light situaitons. Can I get the expertise of the group on how
> to avoid them? If I have to expose supposedly 400 ISO film at 200, that
> limits the usefulness of CN film. I loved printing for rich, black
> shadows in the wet darkroom. I'd like to get them out of scans as well.
>
Wow, a post finally on-topic. And I was just about to unsubscribe!
I honestly haven't had that much trouble with XP2 even rated at 400 (I
usually rate it at 200). Grain aliasing with chromogenic films shouldn't be
much of a problem - there shouldn't really be be any grain to alias as we're
talking more dye clouds!
One thing I find in general with people who scan B&W film is that they set
their black points far too conservatively. Remember that for a wet print zone
0 comes in at 0.1D above b+f. Considering that we aim in wet prints for any
useful shadow detail to come in at zone II/III then you really should be
shoving a good few pixels to pure black when adjusting the blackpoint. I
know the goal is not necesarily to replicate what you do in a wet darkroom
but we are dealing with scanning film and the base does have some variance
in tone (which is what I'm seeing with those speckles in your scan).
So you must look at the actual densities of the shadow area that your
having trouble with. How much above b+f is it where the speckling is still
problematic? It may well be simply not giving the film enough exposure. ISO
film ratings I find are seldom accurate and my calibrations almost always
show that some degree of overexposure is needed.
Saying that your image does seem very problematic. I loaded it into
Photoshop and played with it a bit but couldn't get much out of it. I have
had the occasional problem where the film wasn't fixed properly and actual
silver left in the emulsion interfered with the dye. This is similar to what
I am seeing here.
--
Tony Terlecki
ajt@mrps.demon.co.uk
----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or
body
