agitation and sharpness

Please, I've searched many sources and still have not clear answer.

Which procedure leads to sharper negative (structure of grain): to

agitate twice per minute with two inversions (for example) or once per

minute with four inversions? And more: does this difference affect the

grain size and contrast?

I know this question is little bit confusing, but I've tested both

procedures with different developers and the results seem very

inconsistent I mean sometimes looks sharper frame from one procedure

and sometimes from second (with same film and developer combination).

I'm just looking for one procedure I could use with consistent

results. I like the look of sharp grain pattern. Thank you for advice

and I'm sorry about my english.

The contribution of agitation to sharpness has mostly to do with "edge effects" -- the increase in micro contrast related to developer exhaustion and circulation on a scale of fractional millimeters. This process is related to compensation, in which highlights are compressed by local exhaustion, but edge effects are generally only seen with reduced agitation -- the more you slosh the developer around, the less local exhaustion you'll see. Minimal agitation (every 2 or 3 minutes instead of every 1 minute or every 30 second), extreme minimal agitation (1 or 2 agitations in the complete development cycle after the initial 30 seconds or one minute), and even stand development (highly dilute developer, greatly increased development time, and *no* agitation after the first minute) tend to increase edge effects (and, with some films, compensation) progressively.

 

Overall grain size tends to increase with longer periods in the developer, other factors equal (even when dilution is changed to give the same final contrast), though there are complicating factors raised by changes in solvency of the developer as dilution is increased. Overall, however, you would expect to see larger grain, more edge effects, and greater acutance (what your eye sees as sharpness) by increasing dilution, lengthening development, and reducing or greatly reducing agitation. There is some risk of streaking from bromide drag with long periods of low or no agitation, but it hasn't been reported as a major problem with common combinations of film and developer.

 

Good developers for high dilution and long processing are HC-110 and Rodinal, though there are certainly others that work well. XTOL is also reported to work well at 1:3 or even 1:5 from stock solution, and D-76 has been reported to provide pictorial contrast and excellent sharpness from microfilm stocks at 1:7.

In my opinion, a highly dilute developer and "stand" development will lead to the sharpest negatives possible. Search the archives under stand development. I'm sure you will find plenty of information.

It depends on who you believe. You could read Haist and Henry on the subject of B&W processing, as I did a couple of years ago when I researched this very topic. They disagreed on whether agitation has anything to do with the formation of edge effects. I forget which of these researchers was on which side. I think it was Haist that could not show a connection between agitation and edge effects. Someone will surely correct me if I'm wrong though ;-)

 

For contrast, agitation does make a difference. For a given developer time, more agitation generally means more contrast.

 

As to grain, this I'm pretty sure of. There is no connection between grain size and agitation. The major things that make grain size go up are 1) increasing film speed, 2) increasing exposure, 3) increasing developer time, 4) increasing developer temperature, and 5) moving from a fine grain to an acutance developer. If agitation has a loose link, it is that less agitation leads to longer developer time (#3 above).

 

It's all a trade off, really. You change one thing, you change all the others as well. If you want a sharp but small grain pattern, you should consider using an acutance developer with a slow speed film. Of course, YMMV.

 

Tell us more about what format you are using, what films and developers you have available, and we can probably tell you more.

I have both negatives from hand agitation and from my current (constant) rotary processor. There is no difference that I can see. The idea that you are somehow getting 'less sharp' negatives from constant agitation is, in my opinion, completely false.

 

I would love to be proved wrong by someone with test charts and a microscope.

Jon, have you found any difference in contrast or optimal developing time?

I don't know about Jon, but I can tell you that using a Jobo (continuous agitation) does indeed cut your development times. Or it raises your CI if you don't cut the times. It varies from film to film and developer to developer. I found in developing 4x5 Tri-X in XTOL 1:3, EI 400, 20C, 30rpm, my time to get a zone VIII of 1.3 is about 7.5 minutes where Kodak recommended 10 minutes as a starting point here:

 

http://wwwes.kodak.com/ES/plugins/acrobat/es/professional/productos/Xtol-ing.pdf

 

Like Jon, my sharpness using a Jobo is identical to my sharpness in trays, but my grain is a little smaller due to the shorter processing time.

sounds cool, Hogarth.

 

i have the Jobo 2521 tank. can someone tell me exactly what make and model number to look for on that auction site to use as a turntable?

Probably the one unquantifiable variable in film development is your attitude, your state of mental relaxation. I know this sounds nuts! When you go shoot a roll, just to test a new lens or such, nothing important on the roll, and soup it your normal way in your regular developer, it seems that the grain is next to invisible, tight and even, and you have tonality to die for! Shoot some unrepeatable event for a new client? The grain is noticeable, blocked highlights, etc. Anybody got any better answer than that?

Heh....gotta agree, Al.

 

The important artsy stuff never comes out like the inconsequential portfolio shoots for me...

>Al Kaplan Photo.net Hero, apr 09, 2004; 12:08 a.m.

 

>Probably the one unquantifiable variable in film development is your attitude, your state of mental relaxation.

 

Easy on the LSD Al... yeah, Kodachrome is great and all...

Hey Hogarth and Gaetano,

 

Yep, shorter times indeed. I generally start out with about 15% less time and adjust from there (and as Hogarth states, it depends on the film and dev.). I use a 5 min pre-wash per JOBO. I did a few rolls of Acros a few weeks back and forgot to make the adjustment. Great blacks, no grain, and very hot highlights. Shaved off the 15% on the next couple of rolls and the negs are gorgeous.

 

I'm starting to wonder if 'adjacency effects' are one of those photographic myths that people use to impress oneanother. As I stated before, I'm open to being proven wrong. I just don't see it.

 

(Gaetano! When are you coming to Brooklyn?!)

Thank you all for responses, it's more than I hoped. If you are still interested, I use most of the time HP5 plus 35mm, sometimes FP4 plus. Developers are D76 (I used 1:1 until now) and Rodinal (1:50 until now,I like its look, even if people here didn't recommended it to HP5) Maybe I will try TriX, but now HP5 is much cheaper in some action "3 for price of 2"

Agreed, the whole issue of acutance or edge effects seems somewhat nebulous.

 

For one thing, strictly speaking and according to theory, it will be seen only in areas of distinct contrast (high density/low density on the negative). If a microdensitometer is needed to even measure it, let alone see it with the unaided eye, is it relevant? (Please consider that a rhetorical question, not a challenge to fan a flame war.) My old Ilford Manual of Photography only discusses the issue briefly, as if the matter is largely irrelevant.

 

Perhaps it's relevant to making very large prints out of proportion to the negative size.

 

And is it *practical* (not to say possible) to achieve that acutance without producing undesirably increased grain? IOW, is it possible for any developer to affect acutance and grain entirely separately?

 

At least one forum member has likened acutance to unsharp masking, tho' I don't recall whether the comparison was to traditional unsharp masking or the computer variety. (If the latter it hardly matters to me because I don't care for the look of unsharp masking applied by any image editing software I've tried.)

 

A recent, former participant on these forums was researching this very issue and had provided some potentially interesting examples and challenges to the status quo. Unfortunately he was unable to cooperate with photo.net's rules and terms of use. It would have been helpful if he had been able to share his findings in a better spirit of cooperation. (And please don't consider my last comments an invitation to rehash old grievances. Suffice it to say it's a regrettable deficit to vigorous debate and some valuable information.)

As Hogarth Hughes suggests the literature on this subject appears somewhat

contradictory so anyone who makes an absolute pronouncement could wind

up with pie on their face . Richard Henry notes that since the creation of

adjacency effects is via lateral diffusion the type of agitation should in

principle not matter, and he observes that he obtained adjacency effects with

very vigorous and constant agitation. Yet he notes that research quoted by

Todd reached different conclusions on the nature of agitation.

 

In my own work with certain developers, including Pyrocat-HD, a high

acutance developer based on pyrocatechin/phenidone, I and a number of

other persons have observed a significant increase in the apparent

sharpness of our negatives through the use of minimal agitation procedures

as compared to continuous agitation as in rotary processing. And let me add

that I have used rotary agitation for the better part of the last twenty years for

the development of virtually all of my sheet film . For further information just

look at some of the threads on the AZO forum on stand and minimal agitation

development. This can be observed in both the prints and in an examination

of comparison negatives developed to the same CI using the two different

methods of agitation.

 

It may well be that adjacency effects and the increase in apparent sharpness

that we have observed with minimal agitation procedures can also be

achieved with other developers and constant agitation, as Henry's research

would suggest. However, I would certainly not expect that to be the case with

the typical solvent developers that are popular for 35mm and medium format

films because for a variety of reasons they are very poor candidates for the

creation of adjacency effects. That means in essence that with these

developers one would not expect to see any increase in sharpness with

minimal agitation as compared to rotary processing, an important point to

bear in mind when evaluating the comments of those who claim there is no

difference in agitation method.

 

 

 

Sandy King

I'll second Lex's thought about adjacency only being relevant on edges with fairly

significant contrast.

 

I had an experiment gone awry recently that produced the most extreme adjacency effects

I've ever seen, by a factor of 10 or more. (The experiment was a pre-soak of Sodium

Isoascorbate before stand developing Tech Pan in TD-3. I'm guessing what I got was an

extremely active combined developer that exhausted almost instantly)

 

Luckily the film included a test chart. I had areas calibrated by computer percentage gray

on the printout. Not really valid in any absolute sense, but useful for comparison. Where

there was more than about a 60 percentage point difference in adjacent values, there were

wild, massive blown out adjacency bands. But below about a 60% difference, the effect

rapidly disappeared. Areas of 40 percentage point difference showed no visible adjacency

under a loupe.

 

Jakub: Many English-native Americans have spelling and grammer skills far below yours;

you have absolutely nothing to apologize for.

Observations by Lex and Roger to the effect that adjacency effects are only

relevant on edges with fairly significant contrast is no doubt true. But this is no

insignificant fact. Bear in mind that image sharpness is determined in large

measure by micrcontrast where small, even microscopic size areas of

shadows and highlights meet. The creation of adjacency effects can

emphasize sharpness by helping the eye to visually differentiate between the

two areas of different density.

 

Sandy King

>Sandy King

 

>That means in essence that with these developers one would not expect to see any increase in sharpness with minimal agitation as compared to rotary processing, an important point to bear in mind when evaluating the comments of those who claim there is no difference in agitation method.

 

Exactly. I don't see any evidence of it with my materials, so for all practical purposes, it doesn't exist. The closest I can get to a microscope is an 8000dpi Imacon, but I didn't see any difference with that either. One of these days I'll investigate some pyro and then maybe some of these effects will become apparent. But I have to believe that if the effect is that small, then it may be obscured by 100 other factors, in essence, making it potentially irrelevant. I mean, if I'm off a bit on tilting my 4x5, or my M6's rangfinder is off a hair, these effects are going to be so thoroughly obscured as to be non-existent. How many angels can dance on the head of a pin?

 

As someone who tests photographic materials solely as a means to make photographs and not to test for testing's sake, it seems that this issue consumes much more energy than it is worth.

 

As always, YMMV.

Jon,

 

You appear to have slightly misinterpreted my previous message.

 

The fact that you don't see any evidence of adjacency effects with your materials means only that, i.e. you don't see any evidence of it with your materials. There are various possibilities, not limited to the following: 1) you are already using a developer that gives adjacency effects with normal agitation patterns, or 2) you are using a developer that is not suitable for developing adjacency effects, or 3) there are differences and you just don�t see them. Whatever, if you are happy with the quality of your images then the issue for you should be basically irrelevant,

 

However, the fact of the matter is that adjacency effects definitely exist and can have a very big impact on apparent image sharpness, not just a small impact. There is little if any debate in the literature about the existence of adjacency effects and/or their impact on apparent image sharpness. There is quite a contradiction, however, in the literature as to whether they result from reduced agitation, from developer formulation, or from a combination of the two factors. Since either condition favors the formation of adjacency of adjacency effects they most likely result from a combination, IMHO.

 

As I mentioned in the previous message, many solvent developers used by 35mm and medium format will not produce adjacency effects regardless of the method of agitation. It is not a question of pyro developers versus non-pyro developers but of solvent, fine grain developers versus high acutance non-solvent developers. Many non-pyro developers are potentially capable of producing adjacency effects if used at the proper dilution and with appropriate agitation.

 

Sandy King

Hi Sandy,

<p>

>You appear to have slightly misinterpreted my previous message.

<p>

Now that is entirely possible... :)

<p>

I guess the gist of what I was attempting to communicate was this:

<p>

With the films that I have used (HIE, all the Deltas, HP5+, the Neopans, and Acros) and the developers (D76, HC110, DD-X) I haven't seen any difference in <i>intermittant vs. constant</i> agitation--not that those effects don't exist.

<p>

I think the greater point is this: do such effects make such a dramatic change within the chain of photographic steps to be merit study and testing? For me, no. For you, maybe so. I liked reading about how Salgado 'sloppily' processes his film. With an eye like that, his processing becomes such a small part of the whole effort. When I saw his work in NYC, I can guarantee you my first response was not "EWWW! No adjacency effects! I'm leaving!" I guess I really took to heart that essay "Confessions of a magic bullet chaser". Testing materials solely to test them makes me shake my head. But I guess I'm glad someone does it--so I don't!

<p>

As to whether I'm happy with my images, I'd have to say that I'm about 80% there. But you know what? Adjacency effects aren't going to move me one iota towards that last 20%. That last 20% isn't achieved in processing. It is all about capturing something with meaning.

<p>

Thanks for the chat, I'm off into the late night of NYC with my Leica to go kill some shadow detail (Neopan 1600 @ 3200) and sharpen that vision.

<i>With the films that I have used (HIE, all the Deltas, HP5+, the Neopans, and Acros) and the developers (D76, HC110, DD-X) I haven't seen any difference in intermittant vs. constant agitation--not that those effects don't exist.</i><p>

 

One of the things I understand to be the case with adjacency effects is that they're generally dependent, not only having an acutance developer (of those on your list, HC-110 should qualify at dilutions weaker than B) but of reducing agitation well below the usual "intermittent agitation" standard of one agitation cycle per minute or thereabout. For local exhaustion to produce adjacency by concentration driven diffusion, the developer much stand for long enough to exhaust differentially -- that is, the area developing more silver (i.e. more strongly exposed) has to exhaust enough to become depleted relative to the less exposed area. This will happen more strongly, the longer the film and developer are still between agitations.<p>

 

Mind you, I've never actually developed for edge effects -- I plan to, but I have little free time and most of that is taken just keeping up with my regular developing and scanning, and I have other tests on my plate as well. I'm only quoting what I've read, mostly either here on photo.net or in Anchell & Troop, but the mechanism described makes perfect sense -- the effect referred to is an enhancement of micro contrast across a light-dark border that tends to make the dark darker, and the light lighter, right at the edge. This enhances the contrast of the edge on the micro scale, which is most of what we perceive as sharpness.<p>

 

Bottom line, if your choice of process is rotary (continuous agitation) vs. "standard" intermittent agitation, you'll probably never see adjacency effects with any film, even in a high acutance developer like Microphen. If you reduce agitation (three minutes between cycles, say, or even five) or go all the way to stand development, you'll probably see some edge effects in any developer that's either not strongly solvent, or diluted enough to reduce solvency (possibly in D-76 1:3, or HC-110 Dilution H, but more likely in products like Rodinal 1:200 or HC-110 Dilution F).

My personal opinion is that the developer matters a lot if one is looking for maximum sharpness.

 

Comparing PX in HC-110 1+63 and in a phenidone/ascorbate dev similar to Xtol 1+3, the PA one gives a significantly higher sharpness.

 

Both were used with intermittent agitation every 2 min.

 

I've seen somewhere that ascorbic acid is less active as a phenidone regenerator, so there is more local exaustion in a PA (Xtol and clones) than in a PQ dev.

To Roger,

 

There is a reason for the enhanced and even exaggerated edge effect after presoaking in isoascorbate solution. Ascorbate and isoascorbate oxidation products are acidic. There is a considerable drop in pH in areas of high potential density which retards development. An ascorbate developer can show this effect even in active solutions. There is no need for starvation as we sometimes do in PQ or MQ developers to get adjacency effects. I have seen it in strong ascorbate developers with vigorous agitation.

The border and fringe effects which combine to produce the edge effect we see in a negative are also a part of human vision. That is, they are seen when we look a a sharp edge anywhere, not just in a photo. Chapter 23 of "The Theory of The Photographic Process" has a valuable discussion of this subject. You may find that commonly held opinions are just opinions. In the eye, the effect is called the Mach effect. If you look at a reflection step wedge, you may see that the steps do not look evenly dense near the edges.

 

The author,F. H. Perrin, describes adjacency effects as extremely common. It seems that they are harder to get rid of than to get. Although they are useful for increasing sharpness,they can take the form of apparent uneven development. They increase the sharpness of fine detail as well as coarse, but do not increase resolution. All of this is interesting stuff, worth reading by anyone who id interested in the structure of the photographic image.