Grain clumping, a controversial issue

[Photo Engineer]

Gentlemen;

In the OP, I posted figures from a work by Ross showing that although there is vertical movement in images due to development effects, he showed less than 2 microns of lateral movement of these same images. There was no clumping, just the illusion of clumps by viewing small, random particles down through the film which were separated vertically by quite some distance (on a micro scale).

Searching my copies of Photo Techniques Magazine from 2002 - 2008, I found that from about 2005 - 2008, Dickerson and Zawadski ran a series of articles about grain and granularity in their column called Photography Myths, and in the Jan - Feb 2008 issue published an article entitled "Grain Clumping - Fact or Fable". It was the only article of this type in my collection of this magazine, and since it appears to postdate Ian's referenced article, I assume it to be their last word!

In this article, quoted earlier, they debunk grain clumping with the same argument I presented from Ross in the OP, and dismiss micro reticulation without so much as a mention, simply by inferring that reticulation is a macro effect "the dry lake bed effect".

Since this article written by an expert in T-Max films (and other B&W films from EK) debunks this myth, I think the matter should be considered closed. Dick was one of the chief architects of the B&W film families in KRL up until he retired. We cannot have this both ways from the expert. He either agrees or disagrees with the postulate that grain clumping takes place. He says "doesn't happen". His comments, to me, represent all that need be said.

This is the author, on the subject Ian referred to, in the author's own words.

PE

 

[Ian Grant]

Say what you like Ron, none of that explains the increased grain, sometimes excessive, caused by temperature shifts during processing with some films/

Now could you explain how that happens please. Both Ray & I have seen it, and you know from previous threads that others have a well, they replied after you tried to tell us it can't happen.

Ian

 

[Photo Engineer]

Ian;

Read the article and learn! Also, if you read my posts I have said something appears to be going on. IDK what but it is NOT clumping or micro reticulation! D and Z address this and use an explanation similar to Ross.

PE

 

[Ray Rogers]

Ray do you think the gelatin expands laterally (like with reticulation abnormal process) or parallel to the base? I think the movement is very slight unless the gelatin is ruptured. All data I have seen suggests normal gelatin swells like a sponge accepting fluids then during drying contracts, the grains themselves are kept in place by local hardening, that is they are coated with polymeric hardeners.

The thought of exposed grains wandering about in a 'ocean' of gelatin is pretty funny, if you think logically the migration of an exposed grains into an unexposed area would create quite a few statistical errors, making high quality photography almost impossible.

Going with the 'flow' would suggest that the movement of grains would be proportional to the expansion of the gelatin (with which I have no problem) but it is important to recognise that proportionately they have relatively fixed points-that is as the gelatin swells the grain will move but it will remain fixed WRT the body of the grain which will expand with it.

Grain does not migrate though gelatin.

Your first paragraph is the most important but I plan to address it later.
the others are easier and I have a splitting headache at the moment.

I did not mean to imply the grains were "swimming" in a sea of gelatin; they are held rather tightly actually... and when the sponge that they are entraped in moves, unless there is something to restrain them, I would think they would move right along with the sponge.

If I followed your next to last paragraph ("Going with the 'flow'...") I think we agree.

As for how the gelatin swells, I think it swells 360 degrees in all three planes (X,Y & Z) unless it is restrained in some way.

There are photographs of cubes of gelatin that dry... not into perfect tiny little cubes, but into imploded distorted cubes with ridges and concave planes; the math would be way beyond me but I would say the tendnecy, if unrestrained, would be point center inward & sphrecially outward... thus the 360 number. Being restrained really limits movement, but then again, we are talking about set and hardened gelatin anyway and don't expect that much movement.

I probably agree with you about the movement laterally being comparativly slight (as it is restrained), but it does take place in that direction too.

Dry sponges increase in all 3 dimentions when they get wet.

And, I am talking about a form of reticulation, so I guess that means there is some "rupture" of the gelatin taking place.

 

[Photo Engineer]

Just to clarify something, coated gelatin does not swell in 360 degrees, but rather 180 degrees. The gelatin is very tightly bound to the support and in the case of film, this limits expansion. So, gelatin swells in a fan shape or a conical shape with the apex at the interface with the film. However, when film is processed, we sometimes see a "tubing" or "piping" effect to the film where the film either curls in towards the gelatin or out away from the gelatin. This "piping" is due to the backing and film which are supposed to be "adjusted" such that the film dries flat rather than curled. Films which dry curled have no (or insufficient) backing to prevent the "piping". Usually the curl is towards the gelatin which indicates either expansion of the film base or contraction of the gelatin.

In none of these cases, has it been shown to cause degradation of the image structure in terms of grain or sharpness. It does however, contribute to problems with making prints from curled film. Focus is difficult with curled film.

PE

 

[Ian Grant]

I'll stick with the micro reticulation theory, because at the moment it's the only logical explanation, and we know it's caused by shock stresses to the emulsion due to sudden temperature changes in the process cycle, and the effect has to be called something.

Sometimes terminology is used differently so calling Micro reticulation grain clumping may not be strictly correct but then the visible grain size in a print is similar.

I think it's quite rare for the phenomenon to be particularly noticeable and only with a few types of film which is why almost nothing it written about it.

Ian

 

[Photo Engineer]

This explains things

Guys;

Here is the article. I hope it explains things to you and puts this in the proper perspective. It is in agreement with my previous posts and is Dickerson and Zawadski's definitive and latest statement on the subject. It is undoubtedly in opposition to the theory of clumping and ignores "micro reticulatin". It is also probably the article that Ian refers to earlier, but he misremembered the conclusions and date, as I find no other article on this subject matter by Dickerson and Zawadski back to 2002.

The document is stored at 33% of its size, and expanding it or zooming in will give you full resolution.

Enjoy.

PE

 

[Ian Grant]

Thanks for posting that, it goes on from an earlier article where they show that the developer temperature doesn't cause grain clumping, assuming you compensate development time for the higher temperature.

However it doesn't address what happens when there are temperature shifts between process steps and why that appears as increased grain.

Ian

 

[Photo Engineer]

Yes Ian, they dismiss clumping in all cases in their entire series by summarizing it in this article. Early on they show variations in grain as a function of development time, density, and contrast just as I have posted earlier in the RMSG graphs. And, they dismiss reticulation. We have to see an example, and probably more than one because this is a random (they use the word stochastic) event, as they mention. Eventually, you can see a portrait in grain of your mother-in-law (as they say).

PE

 

[Ian Grant]

Lets approach the issue from a different direction.

Many people write that Rodinal gives excessive grain with 100 ISO films if you use a higher process temperature. Mark mentioned it earlier in the thread. With others it's Xtol & Tmax 400.

Now D & Z and and Richard Henry showed that there's no differences whatsoever as long as you compensate for the development time, I think we can assume as research scientists they kept a fairly constant temperature through out the process cycle. I know Ron and I agree with that, an I used Rodinal for about 20 years with no ghrain issues regardless of the temperature of the process cycle, and with susceptible films.

So the question is why despite processing to the correct gamma/Contrast Index are people getting a lot of grain when others aren't ? It's back to the question of what's happening to the emulsion after development and no one seems to have a clue.

Ian

 

[Ian Grant]

Yes Ian, they dismiss clumping in all cases in their entire series by summarizing it in this article. Early on they show variations in grain as a function of development time, density, and contrast just as I have posted earlier in the RMSG graphs. And, they dismiss reticulation. We have to see an example, and probably more than one because this is a random (they use the word stochastic) event, as they mention. Eventually, you can see a portrait in grain of your mother-in-law (as they say).

PE

The problem is Ron I agree with you (the bold bit of text) that's normally the case.
D & Z are also correct to dismiss reticulation because "classic" reticulation, as I think we all define it, is not taking place.

But then I've seen what we call "Micro Reticulation" as well and it's not related to those parameters, well exposed negatives, correct dev times etc, but excessive grain.

I've just shot a roll of Tmax 100 and the dev was at 24ºC part of the film then went through the rest of the cycle at 24ºC apart from a few frames that where then washed at 12ºC, the other half went into stop, fix, wash at 12ºC. However I doubt I'll see an issue, I've used the same developer - Pyrocat HD - at 27ºC with EFKE PL25 which reticulates really easily with no problems at all because it's atanning developers so hardens the emulsion. Ideally I'd use Rodinal as the KOH would acerbate the problems.

Ian

 

[Ray Rogers]

Just to clarify something, coated gelatin does not swell in 360 degrees, but rather 180 degrees. The gelatin is very tightly bound to the support and in the case of film, this limits expansion. PE

Right. Thought thats what I said.

 

[Ian Grant]

Right. Thought thats what I said.

It was

Ian

 

[Photo Engineer]

As for how the gelatin swells, I think it swells 360 degrees in all three planes (X,Y & Z) unless it is restrained in some way.

As I said, I was clarifying things. Most particularly, this sentence.

PE

 

[Photo Engineer]

As a general reply to you Ian, it is clear that the Kodak people ran processes from 65 to 75 degrees F with variations between solutions wrt temperature. In any event, D and Z make no mention of reticulation of any sort within that range nor does Kodak warn of it. So, since micro reticulaton is apparently not on the table for them, what are we to think. Well, since there is no mention of it, I guess we will continue to argue.

The referenced article(s) describe grain as a variable with process conditions, and one that varies randomly from roll to roll and scene to scene just as the fall of rain varies from storm to storm. The fall of raindrops is not a constant nor is grain.

BTW, just a thought here. If you believe in the arguments in favor of clumping and micro reticulation, then you are giving a powerful argument to the digiheads who can point to a serious flaw in analog with a minor error in processing. (one that probably only a dozen or fewer even claim to have seen and for which no proof is offered).

The bottom line so far is that there is no such thing as grain clumping! If you cannot agree with this, take it up with D and Z, who are experts in the field. If you believe in micro reticulation, you are stretching your imagination IMHO, as arguments that it exist are totally without merit. No documented evidence exists.

PE

 

[Mark Antony]

The bottom line so far is that there is no such thing as grain clumping! No documented evidence exists.

PE

Correct, there has been no documented evidence of grain moving though the gelatin to form 'clumps' The grains remain in pretty much in the same place as they were during exposure:

Physical clumping does not exist
Mark

 

[Ian Grant]

Thanks Ron, that 65 -75º F variation is quite small. We need to be realistic because it's remarkably easy to accidentally be outside those tolerances, particularly in the winter.

Lets still call the excessive grain which is visible when you print an image Micro Reticulation. simply because its caused by temperature stresses in the Gelatin. We all agree that full reticulation is "the dried lake bed effect" and is now rarely seen.

Lets also agree that the term Grain clumping is a misnomer, it's been used because of the increased grain in a mistaken attempt at a description and cause.

Now as this excessive grain is not related to the actual development step but takes place at some stage afterwards.


So we are back to what's going on with the gelatin as a result of the temperature shocks, and this is where the term Micro reticulation makes total sense, because you can see it with photographic papers as well as film. With papers, particularly Glossy RC, this micro reticulation usually just looks liked dull blotchy areas, almost matt. It's unusual and usually only happens when you wash prints for to long, but can also happen with certain toners which is why manufacturers recommend using a hardening fixer before some toners.

Remember Ray's comments about an opaqueness with his Tmax 400 negatives with micro reticulation, and others describe their negatives as being flat and dull when printed. With the Tmax 400 120 films I've seen (and still have) with micro reticulation they also look grainy to the naked eye, but with a 120 film there's a coating on the non emulsion side as well so the effects would be amplified.

So this also explains why a developer like Rodinal is often blamed for increased Graininess, in this case the KOH in the developer will soften the emulsion, greatly increasing the potential for Micro reticulation, which could also be more severe.

I firmly believed John Sexton's advice about Tmax films, which I came to independently in the late 70's - Process the film as carefully as you would color films, and you will get totally repeatable results. and that really goes for all B&W films, and that's what other writers are saying in their advice of tight temperature controls, (John Davies, Bernard Susse etc) although their explanations of the slight reticulation are wrong.

Ian

 

[Mark Antony]

I'm totally unconvinced Ian.
The reason is I have seen zero proof of what you call micro reticulation. You have asserted its existence yet can't put forward a single example or a logical explanation.
It should be easy to prove that this 'increased graininess' is actually in the gelatin rather than grain morphology due to developer kinetics (i.e grains changing shape due to p.h or agitation) simply by enlarging a small area of clear or unexposed film that exhibits 'massive grain' if you can see it in the macro (8x-20x enlargement) then lets have an image of this 'micro reticulation' as you call it a proper scientific (rather than what you feel) repeatable explanation.
I'm quite astonished that you came upon this in the late 1970's also without anyone actually having produced a TMax film- to my memory those came out in the 80's
I think more and more as I read your posts you seem to be describing dichroic fog which can give negatives a metallic look.

Micro reticulation, needs to be proven and the burden of proof is on those who suggest it takes place, If you need Ian I will put you in touch with Kodak research UK when you have a viable sample-my bet is it isn't a gelatin defect at all, but something else related to the kinetics of development.

 

[Ian Grant]

Mark, where have I said that I came across Micro reticulation in the mid 70's ? I said that was when I began processing B&W films to the kind of temperature tolerances between steps etc as you would colour films, and I'd add that it did make a slight difference to consistent quality, particularly with regards to grain.

As to Dichroic fog that's not relevant, I've never seen it with negatives only prints, we aren't describing a metallic sheen either.

Some of us have seen the effects of severe Micro reticulation, and so are in a position to describe it. Although not my films I'm quite happy to send a sample to Greg Davies in the late February/early March when I'm next in the UK. If you've not seen it then it's easy to be sceptical, but I was present when these 3 films were processed, and the only variable was the lack of temperature control after the developer stage.

Before dismissing the idea of Micro reticulation you have to come up with an alternative reason for the increase in apparent graininess due to temperature shifts between processing steps because they occur with some films.

Ian

 

[Tim Gray]

Lets still call the excessive grain which is visible when you print an image Micro Reticulation. simply because its caused by temperature stresses in the Gelatin.

I wouldn't call it that. From everything that is going on in this thread, there seems to be no reason to call it micro reticulation. Assuming that this can happen (I've not seen it, but that doesn't mean anything), there's seemingly no proof that it IS caused by stresses in the gelatin. That's a just a hypothesis.

It sounds like this idea would gain a lot more traction and interest if you called it something else. 'Excessive grain due to temperature variation in post-development solutions.' That's a mouthful, but more accurately represents what you are seeing (I think). You can then go onto say that you and some others have the 'micro reticulation' hypothesis: this is caused by stresses to the gelatin.

It sounds like this whole 8 page thread has gone the way it has specifically because of the terminology used (micro reticulation/grain clumping). The 'fact' which is not being pursued at all is that you and others have noticed increased grain with temp variations after development. If you would stop pushing the hypothesis of what causes that, and instead started pushing the visible phenomena, maybe some heads would get together and try to figure out what IS the cause. Maybe it is even something that deserves to be called micro reticulation.

If there are some suitable samples that people agree represent this problem, I know a guy who runs the electron microscope for the bio dept. I might be able to get him to run a couple scans. If that's even the right tool to investigate this

 

[Ian Grant]

Tim, the term Micro reticulation was coined by a magazine article mid 80's. As the increased graininess seems to be caused by tress in the gelatin creating some kind of surface problem then the term seems apt as it's a very small scale form of reticulation. It is the terminology that's causing confusion, not helped by others calling Micro reticulation - Grain clumping.

There are in fact papers and research documents coving this area, so it's not unknown like Mark has suggested, and the problem was only where to start looking, but add the term stress and you begin to find quite a number of documents related to Photographic film/gelatin

Eastman Kodak talk about "Compression of the silver grains perpendicular to the film plane" due to gelatin shrinkage and "a systematic shift" and in "a tri-axial manner", so my guess is they have some useful information available somewhere

Ian

 

[Mark Antony]

A Mark, where have I said that I came across Micro reticulation in the mid 70's

B/As to Dichroic fog that's not relevant, I've never seen it with negatives only prints, we aren't describing a metallic sheen either.

C/Some of us have seen the effects of severe Micro reticulation, and so are in a position to describe it.



Ian

A/ Here is your quote
"I firmly believed John Sexton's advice about Tmax films, which I came to independently in the late 70's"

I took that to mean you came across T max in the 70's

B/ you certainly can get dichroic fog in film I've seen it-In Tmax-I think Sexton himself found-I'll let you google it.
Here Iv'e found it:
http://www.largeformatphotography.info/articles/sexton-tmax.html
"Some photographers have encountered dichroic fog (an ugly brown metallic stain) on sheet film processed in T-MAX developer."
C/ I think then it would be easy for you to show actual damage to the gelatin layer-until that point-it's almost certainly dichroic fog cased by too cold wash water/stop between the dev and fix.


There are in fact papers and research documents coving this area, so it's not unknown like Mark has suggested

No there aren't if so either produce them or demonstrate the effect, otherwise its just not scientifically proven.

 

[Ian Grant]

Mark, I'm well aware that Dichroic fog occurs with films, and that it's been an issue with Kodak films in particular, for a number of years with certain developers, including Tmax. I've seen rather a lot of it particularly when I worked on Monobaths, I've just not had it with my films

I'll produce/link to the most relevant Kodak or other research/papers when I've finished searching & sifting through it. There's far more written than I expected.

I'm not sure at what point the stress effects at the surface of the gelatin layer(s) can be called damage or within normal tolerance, but Kodak measure them.

No there aren't if so either produce them or demonstrate the effect, otherwise its just not scientifically proven.

You mean you haven't seen or read any, well neither had I until today, but what I've found so far indicates that it's an area Kodak had been researching for many years.

I'll now give you an alternative description of what's been called Micro reticulation - which is also an explanation in itself - optical density artefacts which are stress induced, the rate of swell/shrinkage is the cause of the stress.

Ian

 

[Mark Antony]

Mark, I'm well aware that Dichroic fog occurs with films, and that it's been an issue with Kodak films in particular, for a number of years with certain developers, including Tmax


You said that it didn't occur with film only prints-an I see you've edited you post to take that out.

If Kodak have been researching what did they find can you share the evidence you read today?
Its easy for you to win your argument-show reticulation occurs 'just a little' with small differences in temp-otherwise its all just conjecture without scientific back-up.

Mark

 

[Ian Grant]

Mark, I'm well aware that Dichroic fog occurs with films, and that it's been an issue with Kodak films in particular, for a number of years with certain developers, including Tmax


You said that it didn't occur with film only prints-an I see you've edited you post to take that out........


Mark

Where have I edited that post ?

The bottom line of Kodak's research is that current films are nearly all resistant to quite severe changes in process temperature, same with Ilford. But there are still a few films that exhibit problems, Fuji Neopan 400 being one of them.

Give me a chance to read what I've found so far, some have further references. I only started searching an hour or two ago

Ian