Ok, I'll try it and see - 14 stops huh?! hmmm
----- Original Message -----
From: "Tony Sleep" <TonySleep@halftone.co.uk>
To: <karlsch@verizon.net>
Sent: Friday, October 17, 2003 2:10 AM
Subject: [filmscanners] Re: scanning TMAX 3200
KARL SCHULMEISTERS wrote:
> The reason I question the 'great dynamic range' is that the best color
> films
> only get about 7-8 stops of dynamic range.
False premise alert! I see >14stop range in many; any of the Fuji Superia
films have quite extraordinary range.
> And since chromogenic B&W
> films
> essentially use the same technology/photochemistry, I'd be very
> surprised if
> they can exceed that (slide film is around 4-5 stops).
Again, >14stops here. With conventional B&W film and a solvent,
compensating developer and reduced ISO I've achieved 12 stops at best.
Non-chromagenic TMax and Delta films using tabular grain technologies also
push 14stops, without dev tricks.
But this isn't the whole story. Extreme range isn't much use if you can't
scan or print it. That's the real trouble with conventional films, that if
you do exceed the DR you hit a brick wall. The 'S' shaped curve deals with
highlights by compressing them, and when you reach the flattened top of the
S, that's it. They have great midtone separation, which is pictorially
important, and why a lot of people love them.
CN, chromagenic and T-grain films are rather similar to each other and more
linear. Their extended range is all located at the highlight end, where
they go on building density after conventional B&W has blocked. These
long-scale highlights can be wretched to print on bromide, which is why
paper formulations got changed to cope (eg Ilford MG4 RC - the non-RC
seems to be different). Which makes getting all the highlight detail
easier, but you pay for it in flattened midtones unless you use a hard
enough paper to make highlights awkward.
At the same time shadow separation tends to be a little weak. Downrating a
bit helps preserve this.
IME chromagenic is much easier to use and print because dye density doesn't
build to the same extent. With T-grain films, highlight detail is there
alright, but the OD is more severe, and a pain to burn in. But both do have
rather flat midtones, which a lot of people dislike.
When it comes to scanning, the softer negs (lower ODR) of chromagenic dyes
makes life very much easier. The softer edges of the dye clouds also
help avoid grain aliasing issues.
Really, if you are shooting B&W with the intention of dig workflow, you
have to try TCN or XP2. Not everybody likes the lack of grain and MF-like
tonal smoothness, but personally I love it, and used XP1 for many years
pre-scanning.
The midtone lack of life, an issue on bromide, just isn't a problem when
scanning. The downside of chromagenic is a slight loss of sharpness
compared to the hard edges of grained films, but hey, now we have USM!
Overall, TCN fits beautifully into a scanning workflow, but be prepared to
adjust curves and levels to put some life back into those midtones. As with
colour neg, it's often desirable to dupe the image, apply different curves
and/or levels for shadow-midtone and highlights, then layer one over the
other and selectively mask or erase to give a composite.
I don't like the way TCN/XP2 pushes at all. For >ISO400, TMax3200 or (as I
later came to prefer) Delta3200 are miraculous, specially when used at
ISO1250 or 1600 respectively. But they're buggers for grain aliasing.
If you really want 'fast' though, have a look at www.halftone.co.uk/10d/
for the silly stuff you can do with a digicam and post-prod...
Regards
Tony Sleep -
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