[Leica] a lesson on Densitiometers

[Alastair Firkin <firkin@ncable.net.au>]

thank you jeff, I have always avoided the "technical" stuff, but as I 
work more and more in the darkroom, there seems to be more reasons to 
have access to one. I like your comment about never having time to take 
images other than tests, this is exactly why I have avoided doing my 
own film speed testing: but perhaps I should sell cameras not avoid 
densitometers.

Cheers
On Tuesday, Jul 1, 2003, at 14:32 Australia/Melbourne, Jeff S wrote:

> Ansel Adams (The Negative) and Phil Davis (Beyond The
> Zone System) have pretty well documented the "how" and
> "why" of densitometer useage better than I will
> attempt. But in brief, if you really want to maximize
> your control over print tonality and contrast, sooner
> or later you're going to find one very handy.
>
> One of the most basic uses is to determine the
> effective film speed for a given film/chemistry combo.
> The most direct approach is to expose a series of
> frames of film at Zone I, at manufacturer's
> recommended film speed, and a series of others at
> above and below it. Process per manufacturer's
> recommendation and locate the frame which corresponds
> to X density units above filmbase+fog, and you've
> found your effective film speed for this particular
> film/chemistry combo. Exactly what "X" is seems to be
> subject to some debate, but Adams suggested 0.10
> density units over filmbase+fog. Maybe someone could
> chime in with suggestions on whether this figure needs
> to be revised when working with newer emulsions like
> Acros.
>
> Once we've established the effective film speed, we
> can go on to determine proper N, N- and N+ developing
> times.
>
> The problem of devoutly following the Zone System is
> that you'll probably never take another photo again,
> save for Zone I and Zone VIII test exposures, because
> in theory, you should run the tests for EVERY meter
> and shutter that you own. And I don't care how good
> you are, getting a precise 0.10 Zone I test exposure
> repeatedly is really tough, particularly if you're
> using mechanical shutters. For this reason, I think
> David Vestal nailed it in a column about his relaxed,
> "sort of Zone System" (Vestal At Large, Photo
> Techniques, issue ??)
>
> Heiland (of Wetzlar!) has a unit that looks especially
> handy for the b&w photographer: It's a simple
> digital-readout model that works in both transmission
> (for examining negatives) and reflection (good for
> evaluating prints) modes. But many of the used
> densitometers on eBay should work as well.
>
> Jeff
>
>> Date: Mon, 30 Jun 2003 12:33:04 +1000
>> From: Alastair Firkin <firkin@ncable.net.au>
>> Subject: [Leica] Digital has WON? Yes, but how about
> a >lesson on Densitiometers
>>
>> Speaking of the darkroom: any one like to tell me
> about >densitometers
>
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Alastair

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