Interesting idea, Bill. While I used to use XP-1s variation
in contrast, higher speed in contrastier lighting, I never
thought of doing so rigorously as would need to be done to
approximate the zone system. I don't see why it wouldn't
work with a little serious testing.
--Tom
William Robb wrote:
>
> Tom inadvertantly brings up the beauty of the chromogenics. They
> are the films that allow the roll film camera shooter to
> actually utilize a meaningful zone system of exposure.
> Stay with me on this for a moment. I hope I can make some sense
> here.
> The traditional B&W shooter has 2 controls at hand. We use
> exposure and development to hit a specific contrast range. That
> contrast range is the one which prints well on the paper we like
> to print on, more or less. So, within this framework of 3
> variables, we go to work. So, what happens when we lock in
> another variable. The contrast range is already locked, now we
> lock the development with the use of the C-41 process (Has
> anyone actually tried to push XP-2?? Just curious). So, what we
> need is a wide latitude film with a characteristic curve that
> will give a different contrast range throughout it's exposure
> slope. For example, it may have a somewhat steep slope at the
> lower end, flattening out as the exposure increases. This is
> what the chromogenics do.
> More than once, I have gone off on a rant about exposure ranges
> and film latitude. If the scene fits within the film's usable
> range, then a usable ( not neccesarrily optimized ) print can be
> made from the resulting negative.
> Dye image films have an extraordinary usable range. They don't
> block up the way silver image films do. XP-1 had a range in
> exess of 10 stops. I bet XP-2Super and T-400CN have longer
> ranges.
>
> The average scene is less than 7 stops, and is closer to 6
> stops.
> Go measure some scenes if you don't believe me, but make sure
> your meter is colour blind, or else your measurements are
> useless.
>
> Tri-X (the favourite film of the PDML, according to Albano's
> survey) has a very long toe with a moderate slope. What this
> means it that Tri-X has a lot of exposure latitude. It also
> means that Tri-X responds well to development controls. I don't
> know if this means anything in context, but it just came to
> mind.
>
> Anyway, we were talking about exposure controls. The idea is to
> fit a particular exposure/development combination into a given
> scene. Since the chromogenics seem able to give a variable
> exposure slope depending on exactly where the exposure range
> sits on it, it is possible to use meaningful zone system
> controls with them.
>
> Sometimes we forget that St Ansel invented the Zone system when
> emulsions were thick, and had somewhat short exposure ranges.
> Now, emulsions are thin, and have very long ranges.
>
> Now, rather than having a long toe, we have a long shoulder.
>
> The Zone system user can work with it, though it is not a
> replacement for a darkroom and custom film processing and
> printing. I just wish the emulsions were harder and more
> permanent.
> William Robb
>
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