changing minimum variables for finer grain & acutance

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based on what seems to be the universal recommendation for folks starting out in the darkroom, i've picked one film/developer to concentrate my efforts on... i'm using plus-x (35mm) and d-76 1:1

i'm getting mostly what seem to be nice printable negatives, but since i started using a grain enlarger for focusing my prints i'm noticing different grain characteristics that seem to vary from roll to roll... what i mean is some negatives have uniform small grain while others have some large grain as well as small grain (the large grains i'm referring to look more linear than spherical)

what i'm thinking is my agitation may be causing this, i've been using the kodak recommended times & agitation (20oC, 7 mins with 5 initial inversions, tap then 5 sec at each 30 sec interval) i've noticed that i'm not always giving the same number of inversions for the 5 second agitation, should this make a big difference? (in case you're thinking other variables, this is all from the same stock soln of d-76 and i'm confident that my temperatures have been uniform)

also i've noticed some rolls seem to enlarge better to larger prints where others kind of start falling apart sooner.... this is comparing shots from same lens/camera in similar shooting conditions

is all that just normal variability or can you see something i'm doing wrong or leaving out? any suggestions or comments are appreciated

thanks, joe

-- Joe H (joe1013_@excite.com), March 20, 2001

Answers

Fine grain developers (as d-76) don't only develop chemically but also physically. Physical development is "encouraged" by agitating more often. The effect is that grain is reduced but also acutance (edge sharpness). When developing for acutance just limit agitation to maximum once per minute.

-- Marc Leest (mmm@n2photography.com), March 20, 2001.

Trying to do everything exactly the same each time (including the number of agitations) is the key to consistency. Some people claim you'll get better tonality with slower inversions--one every two seconds or so. And, as was already mentioned, ten seconds every minute (or four to five inversions) may give you better sharpness at the expense of a little more grain. Another consideration is that D-76 tends to gain contrast as it ages, and grain usually follows contrast.

-- Brian Hinther (BrianH@sd314.k12.id.us), March 20, 2001.

Agitation certainly matters and you can probably see a contrast difference by adding or subtracting just one inversion per set. Watch your temperature too, including the wash. Gross changes lead to reticulation, but that doesn't mean that smaller changes have no effect. Grain is actually clumps of grain and supposedly they're affected by temperature change and even the way the film is dried. There are some interesting errors that can occur with grain focusers- look for a copy of Ctein's Post Exposure at the book store. He covers a bunch of things you might find useful. BTW, you probably wouldn't notice the things you're seeing if you were using multiple films and developers, so the stratagy has proved itself sound!

-- Conrad Hoffman (choffman@rpa.net), March 20, 2001.

I second the suggestion about keeping the wash water at or about the same temperature as your processing chemicals. I think the range is plus or minus 5 degrees, but certainly no more than this. I had a similar problem with wide variability in image quality, and keeping the wash temp at the right temperature led to consistently better quality images.

-- Distagon2 (greg_jones@mk.com), March 20, 2001.

Joe, Grain,or granulation, or whatever you notice in your prints, depends just on the following variables: emulsion, exposure, developer formula, development techniques (all of them), magnification, enlarger source of light, optics and (probably, forgetting something else) even paper grade. So, open yours eyes, there's a lot to learn in this field. Good luck.

Cesar B.

-- Cesar Barreto (cesarb@infolink.com.br), March 20, 2001.



Another alternative is that there's absolutely nothing wrong with your processing technique at all, and it's the film that's at fault.
All film has to go through a 'ripening' stage, which critically affects the grain structure. The majority of this ripening is done during manufacture, by storing the raw film for a time at a controlled temperature, but ripening continues until the film is processed.
Incorrect storage, at high temperatures or humidities can drastically affect the grain of a film

Do you buy your film in batches and keep it refrigerated?
If you buy on a piecemeal basis, then you must expect some variation, however consistent your processing is.

-- Pete Andrews (p.l.andrews@bham.ac.uk), March 21, 2001.


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