maximum black on film

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Hi,

Why when examining the leader of film do professionals always look for maximum black ?. is this to ensure full developement ? and is this a problem when you undervelop on purpose ?

Ta ade

-- adrian (adriancobb@hotmail.com), September 01, 2001

Answers

O.K.- First off, I would not consider myself a professional, although some of my income is derived from photography, maybe 20%. Most of that comes form shooting color neg film. My black and whites, hoever, are almost completely "mine" in that I only have to satisify myself. When I use Stand development, I will rarely see a deep d-max on the leader. I never worry about it.

Although I suppose that One who rigidly sticks to convention would demand D-max on the leader.

-- Mike DeVoue (karma77@att.net), September 01, 2001.


I've never heard of anyone looking for "maximum black" on the leader.

The actual D-Max of film/developer combinations varies; about the only thing looking at the leader would tell you would be if you had a gross developer failure.

-- John Hicks (jbh@magicnet.net), September 01, 2001.


Arian:

Maximum Black on the leader is what you get anyway, as it is usualy fully exposed and developed as much as anywhere else on the neg-I assume you are talking 35mm.

This is OK but only relative. What counts is the range of tones between "Bmax" on the neg and the base density plus fog on a totally non-exposed portion. Books on sensitometry will explain this, as will Ansel Adams' "The Negative" and Fred Picker's "Zone VI workshop", both necessities for a serious amateur b&W shooter.

Then what REALLY counts is the maximum black(Dmax) on the paper. This is a function of the print exposure time, the type of paper and the deelopment time. Picker bases his world on a contact proof that has a series of exposures, from which you chooes the last exposure test time that is not blacker than the one before-that is Dmax on the paper where it counts. The contrast range of the paper or the filter used then determines where the brightest white with texture falls:- Zone system basics, at least as I understand it.

Cheers

-- RICHARD ILOMAKI (richardjx@hotmail.com), September 01, 2001.


I'm no pro, but I do measure the density of the leader on each roll I process. Because I use XTOL at 1:3 dilution, and there have been many reports of development failure, this measurement provides a reality check on how consistant my development is. So far, the answer is "very". One can assume the leader is reasonably well exposed, and my normal density is about 2.0. One can also assume that this will be the highest density found on the roll. One of my concerns is that doing a "pull" will result in very low Dmax, which isn't really what you want. Ideally, the film curve would rise at the desired CI, but continue on to a high density, recording a huge dynamic range. With XTOL, the Dmax is quite low already, and I question the wisdom of using it to record very wide range scenes. Other developers give more density before the curve levels off into a shelf.

-- Conrad Hoffman (choffman@rpa.net), September 01, 2001.

There is no leader on sheet film.

-- Dan Smith (shooter@brigham.net), September 02, 2001.


If the leader has been exposed to light for a long time, then it will no longer show maximum black. True solarization (less density for more exposure) is rare with modern film, under normal exposure conditions, but it can still happen to the leader of a 35mm cassette left exposed to brightish light for a long time.
If you're referring to transparency film, then looking at the margin, or any other unexposed area, is a part of the assessment of processing quality.

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 04, 2001.

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