Edge effect and acutance

[cliveh]

I think what you are discussing here is the Eberhard effect, where corresponding macro and micro densities for the same exposure produce Mackie lines.

 

[Lachlan Young]

Lachlan,

Thanks for taking time for the lengthy explanation. Much appreciated!

I would, however, appreciated it if you could unpack the above sentence for me. I can't seem to make heads or tails of it.

TIA

Doremus

Very short answer: if staining developers and/ or reduced agitation schemes worked under rigorous scientific and double blind perceptual test conditions, they would have been commercialised/ made standard technique a long time ago. Cf. with the work that led to CD3/ CD4/ CD6 where modifying PPD turned an exceptionally useful but potentially very dangerous component into a vastly safer one - and litho film process techniques for optimal halftone dot formation. The falsifiability (if you know your Karl Popper) aspect refers to the ease of using very mainstream developers and basic process controls to produce results that would make people with priors in staining developers and reduced agitation swear blind that it was done with staining developers and/ or reduced agitation. Some of the most startlingly sharp (and yet fine grain) results I have seen on Delta 100 came from full strength ID-11 and continuous agitation, but with consistent exposure, process time and process temperature controls (which means within reasonable error bars).

you wouldnt happen to have any suggestions on 8x10" film that would be capable of similar characterstics as Tmax400 (for a lesser price)?

You're not going to like it, but my recommendation is to cut your cloth according to your purse. You either pay for Tmax 400 and get Tmax 400 or you pay less and go for something that might be somewhat different. How big are you enlarging?
For example, Ilfosol 3 will definitely produce obvious adjacency effects with HP5+ - but the visual granularity will kick in earlier than on TMax. On the other hand, I often find that I prefer Delta 100's colour sensitivity to Tmax 400's, so there is a lot more to consider than sharpness and granularity, especially with 8x10 and all current Kodak and Ilford films (all of which are designed to produce adjacency effects in ID-11/ D-76, never mind PQ developers that have the potential to exaggerate them further).

 

[pkr1979]

You're not going to like it, but my recommendation is to cut your cloth according to your purse.

Not at all, realism is much appreciated. Trying out and experimenting with new films can also get costly, and time consuming - even with smaller formats. In that sense continuing with Tmax400 might not be that much more expensive. Particularly since Ive been using that for land/city-scapes, which isnt really what I shoot the most. Its intended for use with Lupex/Silver Chloride paper, so grain is no issue.

 

[Doremus Scudder]

Very short answer: if staining developers and/ or reduced agitation schemes worked under rigorous scientific and double blind perceptual test conditions, they would have been commercialised/ made standard technique a long time ago. Cf. with the work that led to CD3/ CD4/ CD6 where modifying PPD turned an exceptionally useful but potentially very dangerous component into a vastly safer one - and litho film process techniques for optimal halftone dot formation. The falsifiability (if you know your Karl Popper) aspect refers to the ease of using very mainstream developers and basic process controls to produce results that would make people with priors in staining developers and reduced agitation swear blind that it was done with staining developers and/ or reduced agitation. Some of the most startlingly sharp (and yet fine grain) results I have seen on Delta 100 came from full strength ID-11 and continuous agitation, but with consistent exposure, process time and process temperature controls (which means within reasonable error bars).

Lachlan,

Thanks for the explanation. Yes, I'm familiar with Popper and his Falsification Theory. There's been a bit of criticism of that, IIRC, as well. Still, it's a valuable idea.

Whatever the case, edge effects (Eberhardt/Mackie Lines/whatever), should be easily observable with a microscope and measurable with a microdensitometer. So, in lieu of your belief that the free-market economy would have adopted staining developers if they were better at producing adjacency effects out of profit motive (a notion that excludes a lot of other considerations manufacturers might have, e.g., liability for toxicity, ease of use, assumption that better developers would be as, or more, profitable than slightly-less good developers, etc.), I'd like to see some data. I'm not aware of any, but there must be some out there. Maybe you could point me in the right direction?

You state that standard developers (e.g., ID11/D76) used in a normal way (e.g., standard agitation) can produce results equal to or better than more esoteric developers that are not in mass production, like staining developers, and reduced agitation regimes. I certainly won't dispute that in terms of grain and acutance. I'd be really interested, though, in seeing some evidence that the adjacency effects are also similar.

I do know that I never observed the Eberhard Effect (double Mackie Lines of increased and reduced-density borders on the interface of high and low-density areas) with my grain magnifier until I started using PMK along with slightly reduced agitation for the second half of the development time. The effect is quite easily visible with my Peak grain magnifier at standard enlargement ratios (4x-5x). Other negatives of mine developed in HC-110 and D-76 do not exhibit this effect.

Any documentation you can direct me to?

FWIW, the main reason I like the PMK stain is not for extra sharpness or even the edge effects, but rather the grain-masking effect it has in the areas of low negative density. Clouds, especially, are rendered very smooth, even at rather high enlargement ratios.

Best,

Doremus

 

[DREW WILEY]

One chooses a film with several properties in mind - speed, curve shape, grain structure, availability in a given format etc.
Edge effect can potentially be manipulated in several manners.

Responding to the previous post by Doremus, PMK in combination with HP5 has an unusual effect : a blended "watercolor grain" which doesn't look "grainy" at all, combined with enhanced edge effect. At the right magnification this can lend an almost etched look to highly detailed subjects. But I limit that acceptable magnification to around 3X; and for that reason, I only shoot HP5 in 8x10 format.

TMY400 has good native edge effect in many developers including pyro. But TMX100 doesn't. It has great detail capacity, but rather poor edge effect unless specially treated. I use Perceptol 1:3 to attain that, which has a quite different personality than Perceptol 1:1, and allows just enough grain growth to enhance the edge effect too.

FP4 has good edge effect. And in small format, Pan F has its exceptional "wire sharpness" due to that, especially with a staining pyro due to the better highlight control.

Then there's unsharp masking, which allows a high degree of control to edges. But just like over- or overt- sharpening in digital workflow, you have to be careful not to overdo it. The difference is, the optical darkroom method is not lossy of any fine edge detail, whereas the digital route is.

Viewing grain structure under a regular microscope can be misleading unless you are an expert at it. I did that the other day, and just making real prints tells one a lot more. Printing paper often sees things differently than we do.

 

[Craig]

, never mind PQ developers that have the potential to exaggerate them further).

PQ: would that be something like Microphen?

 

[Lachlan Young]

PQ: would that be something like Microphen?

Yes. And a great many of the derivatives (even Pyrocat is effectively a derivative, though down a dead-end).

 

[GregY]

Lachlan,

Thanks for the explanation. Yes, I'm familiar with Popper and his Falsification Theory. There's been a bit of criticism of that, IIRC, as well. Still, it's a valuable idea.

Whatever the case, edge effects (Eberhardt/Mackie Lines/whatever), should be easily observable with a microscope and measurable with a microdensitometer. So, in lieu of your belief that the free-market economy would have adopted staining developers if they were better at producing adjacency effects out of profit motive (a notion that excludes a lot of other considerations manufacturers might have, e.g., liability for toxicity, ease of use, assumption that better developers would be as, or more, profitable than slightly-less good developers, etc.), I'd like to see some data. I'm not aware of any, but there must be some out there. Maybe you could point me in the right direction?

You state that standard developers (e.g., ID11/D76) used in a normal way (e.g., standard agitation) can produce results equal to or better than more esoteric developers that are not in mass production, like staining developers, and reduced agitation regimes. I certainly won't dispute that in terms of grain and acutance. I'd be really interested, though, in seeing some evidence that the adjacency effects are also similar.

I do know that I never observed the Eberhard Effect (double Mackie Lines of increased and reduced-density borders on the interface of high and low-density areas) with my grain magnifier until I started using PMK along with slightly reduced agitation for the second half of the development time. The effect is quite easily visible with my Peak grain magnifier at standard enlargement ratios (4x-5x). Other negatives of mine developed in HC-110 and D-76 do not exhibit this effect.

Any documentation you can direct me to?

FWIW, the main reason I like the PMK stain is not for extra sharpness or even the edge effects, but rather the grain-masking effect it has in the areas of low negative density. Clouds, especially, are rendered very smooth, even at rather high enlargement ratios.

Best,

Doremus

Exactly this!

 

[john_s]

Yes. And a great many of the derivatives (even Pyrocat is effectively a derivative, though down a dead-end).

I have never thought of Pyrocat being a derivative of Microphen, as they are rather different to each other. In fact, they are the only two developers that I regularly use, and for very different subjects.

 

[Lachlan Young]

I have never thought of Pyrocat being a derivative of Microphen, as they are rather different to each other. In fact, they are the only two developers that I regularly use, and for very different subjects.

What initially matters in terms of thinking of familial developer relationships is the proportional relationship of developing agents. The rest, ie silver solvent(s), buffer (borate for fine grain, carbonate for higher definition, metaborate for trying not to damage random rolls of poorly hardened emulsions in commercial process environments), oxygen scavengers etc, are there to refine the aim of the rest of the design goals. ID-68 is a derivative of D-76/ ID-11, with optimisations, but if you start with D-76, sub in Phenidone at the usual 1:10 ratio for Metol, swap the HQ at 1:1 for an isomer that produces a 'better' dye stain, remove the solvent/ oxygen scavenger (i.e. the sulphite) to allow the HQ to act as a dye coupler, and then replace the borate buffer with carbonate, you get Pyrocat. That's why Microphen can seem to produce more visible granularity/ sharpness than D-76 (not really because of fractionally lower sulphite levels in ID-68/ Microphen) and why Pyrocat should produce adjacency effects - because they are effectively both PQ type developers within what seems to be an optimal relationship range for PQ/ PC to produce adjacency effects. It's just that Pyrocat's lack of solvency cuts off access to further adjacency effects. Bromide (really probably iodobromide) drag is effectively an extreme form of adjacency effects.

I would suggest that an interesting experiment might be to take ID-68, replace the borate buffer with carbonate and see what it does at various dilutions, and possibly with different levels of Phenidone. Maybe also worth seeing what adding small amounts of more aggressive silver solvents could do.

 

[Keith Tapscott.]

I would suggest that an interesting experiment might be to take ID-68, replace the borate buffer with carbonate and see what it does at various dilutions, and possibly with different levels of Phenidone. Maybe also worth seeing what adding small amounts of more aggressive silver solvents could do.

Or try FX37.

 

[Augustus Caesar]

Or try FX37.

It's supposed to be terrific, but I have somehow failed to try it.

 

[Keith Tapscott.]

It's supposed to be terrific, but I have somehow failed to try it.

Have a look at the Flickr page of Peter Elgar (Pentax Pete)

He has used it with a few different films.
FP4 Plus seems to give him very full film speed. according to his findings in FX37 diluted 1+9 (not a typo) 11 minutes at 68 degrees Fahrenheit. Fine grain too.

As with any film and developer combination, run a test for exposure and developing time.
Perhaps he will comment if he reads this.