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Grain, Micro reticulation & B&W fim process temperature deviations

Why should I bother to even begin to read your reply .

1. AT NO TIME IN THIS THREAD HAVE WE USED °F - so why bring that in now ?

2. Comparison of Tmax 100 to 400 is not relevant to slower/ high contrast films like Pan F (and Plus X0, so is totally irrelevant.

3, Well before you became involved in the previous 2 threads I said high pH devs may be the problem with temperature deviations, so now you agree


Are you unable tor read: Micro reticulation is Grain Clumping not Old style gelatin crazing reticulation, I've made that very clear ALL along, to ensure no mis-interpretation. That's other peoples definition from 30 odd years ago, we have to accept that even if we might think it's not the best terminology.

So now your thinking in ° F you agree. So what were all the other posts about ?

Ian



 
Ian;

The Kodak data tables I have here on process variations and the data on their web site are in degrees F, but I posted an approximation in degrees C as well.

If you go here: http://www.kodak.com/global/en/professional/support/techPubs/f4018/f4018.pdf you will see Plus X 125 which is a "slow film" compared to some others. If you compare that to the other film data I suggested seeing, then you will see that on page 8, the contrast ranges vs development times vary with developer vs time in much the same way as the other films I referred to. It is a matter of picking and choosing. If one picks the wrong time or developer, contrast can be too high or too low. Note that degrees F is posted on this page before degrees C. I use either and convert roughly in my head back and forth. Not that I think any of this will satisfy you for some reason.

Now, as for the clumping, I would like to give a more complete explanation for my reluctance to go along with the fact that a tiny (+/- 5 deg F or 2 deg C pick either one) would cause a problem. Silver halide, precipitated without gelatin gives a sandy aggregate that falls to the bottom of the reaction beaker in a large loose lump! As you add gelatin in an increasing concentration series of gelatin to the beaker before making the silver halide, the grains are suspended better and better and become smaller and smaller by means of a process called peptization. This forms a real chemical bond between gelatin and silver that takes a bit of energy to break! (more than those few degrees noted above)

When you dilute the emulsion to coat it, it gains a tendancy to create this aggregate or at least it can clump. Mees refers to this process as a non random distribution of silver halide crystals in the coating. If these clumps occur during precipitation or during coating, then they are seen as clumps of silver in the final image and therefore are considered a manufacturing defect! This type of coating should be scrapped by the Mfgr. or the user should report it to the Mfgr. for replacement. However, it is hard for a user to "prove" he did not do it in the process.

If the clumps are not present until during or after the process, it would take a relatively high level of abuse to cause the effect to take place. Of course, this would again be hard to prove.

The only evidence that I can offer is twofold, and mentioned before. 1. It takes high energy to "de-peptize" silver halide from gelatin and 2. The amount of energy would cause other harm as well including reticulation.

So, I am caught in a dilemma here having a respected group of APUG members saying one thing but then another cannot show it and John Sexton says that a strip of film in question has no problem. What do you expect me to say or do. I will listen and watch for results. Ian's reference says a lot in very unscientific terms and presents no evidence whatsoever. Ian presents anecdotal evidence as well. It seems to go back to Rodinal, but I can't say either way without proof.

And, I always advise tight lab practices. Nowhere have I said otherwise. However, Kodak gives a range of temps for the final steps (including a stop bath) from 65 to 75 deg F or 18 to 24 deg C. So, within this range they say there should be no problem with their films. See page 6 here: http://www.kodak.com/global/en/professional/support/techPubs/f4018/f4018.pdf for an example of what Kodak says is acceptable.

PE
 

Michael;

See the Kodak data at: http://www.kodak.com/global/en/professional/support/techPubs/f4018/f4018.pdf and in my post above. The shock is not all that great.

PE
 
First of all, reticulation generally occurs because of large changes in temperature between one solution and another. Microreticulation, if it exists, might happen with lesser changes. The main thing that this says is that the solutions should all be at the same temperature. What temperature does not really matter, as long as it is reasonable (say 15 to 29C, with appropriate time compensations). But most films today are superhardened in manufacturing. That means they resist reticulation very effectively. You might notice that Kodak recommends that the solutions all be with in a 4C range of one another (+/- 2C). That probably works fine for even the fussiest photographer.

There are other things that could effect grain clumping and similar behavior before processing. I'm no expert here, but film handling and storage would be high on my suspect list. Could leaving the film for two days in the car in July in Tuscon possibly have affected it?
 
Quick note from someone with scientific training working in an industry with a very unscientific nomenclature:

The fact that someone has used the word "microreticulation" to describe a phenomenon unrelated to "reticulation" does in no way indicate that this is the correct term for it.

The best thing to do with dubious or misleading nomenclature is to stop using it immediately. Continuing its use will only perpetuate the confusion.
 

The problem is that in research both Fuji & Kodak are referring to controlling the adverse effects of gelatin swelling & shrinkage as "reducing Reticulation" even when there's no classic old fashioned "Reticulation" and both were still doing active research to reduce it until at least 2000. We are left with the terms Micro-reticulation or grain clumping to describe the increased graininess as they've been in use for many years, no other term has been used.

Some research relates to B&W films just prior to the release of Tmax, but most later work is for colour emulsions.

Fuji in particular were trying to control the rate of swelling of emulsions, and it's the speed of change that is the critical factor, which is the same when it comes to increased graininess.

Back in the 70's Mason (Ilford) stated that that "Graininess" is often greater with developers with a high pH, and also partially due to much softer gelatin, and it's no co-incidence that the film some people have unexpected issues with is Acros, particularly in Rodinal. Soft emulsion, high pH developer.

It's there in the text books but with no discussion at all, and increased graininess is not caused by a high pH itself, some Kodak B&W film developers like Duraflo RT have pH's > 12, and grain stays normal, and with many films Rodinal gives excellent fine grain.



My own experience is that of the films I've used Tmax 400 (old & new) in Xtol shows the greatest increase in Graininess with poor temperature control, from very excessive, which I saw first hand with someone else processing their film (I have all the negatives from those 3 120 films) to a slight increase on the odd occasion I've been less careful, and I was using Tmax 400 in 35mm where any increase is easily noticed.

The vast majority of people process and wash films within reasonable parameters and never see an issue. It's also apparent that not all films and film/developer combinations are equal, some very much less tolerant than others.

Ian
 
Fortunately I have never seen any of the effects mentioned in this thread. I do keep my chemicals at room temperature with little variation. The only variable is the wash water which depends on the season. Even if the wash water is hotter or colder than the chemical temperatures there is no noticeable grain clumping after the fixing is complete. I have processed my film in this manner for 40+ years with developing temperatures from 14c to 30c with no ill effects. Of course at higher temperatures I must dilute my developer to obtain a suitable developing time. Plus-X and Tri-X in D-76, ID-11, Arista 76 have been my staples.
 
I think I've seen this effect, too.

My temperature control has been a bit sloppy as I have always been satisfied with the results until this. I "measure" wash water with my hand and leave it flowing from the tap, so it can change suddenly.

So, I shot a roll of Neopan 400 - I've heard of people getting the classic reticulation when they use hair dryer to dry this particular film too quickly (with temperature too high). So I was careful with drying, and didn't get any classic reticulation - but the grain was unexpectedly high for a 6x6 frame. Developed in XTOL 1+1, a 9.5"x11" print of a 6x6 frame showed a grain I would expect from a 35 mm frame developed in Rodinal, rather than 6x6 frame in XTOL. It looked exactly like grain. Later, I heard about this "micro-reticulation".

The problem is, I haven't shot any Neopan 400 other than this roll so I really can't compare. And I don't have any notes of the possible temperature shifts and I can't remember so well.

But just my two cents.
 
I think that high temperature storage might cause this effect.

I think that proper nomenclature might help here too. The term was invented for a magazine article as I understand from the posts here.

I know of no Kodak R&D on clumping or reticulation in the late 90s or early in the 2000s. R&D in B&W and color was severely restricted to main stream improvements such as 2 EQ sensitization and the Ektar films as well as Cine films in general. Reticulation was judged to be a solved problem after the release of the new hardeners and clumping during coating (as per Mees) was solved in the 60s. I would appreciate some references if anyone believes otherwise as I am open to helping solve this apparent problem.

But, beauty is in the eye of the beholder and in a previous post, negatives judged by the owner to have clumping were judged by John Sexton to be ok. Since John was there, and he is one of our great photographers, and one who works with Kodak and is reportedly aware of this prolem, I have to feel that there is some of the judgments being subjective.

Look at Kodak's current temperature range in the reference I cited above.

PE
 

Maybe we are quite wrong to imply all when saying “Current B&W films” and talking about the degree of hardening

Reading Fuji's abstracts in quite a few Patents it appears that with some Tabular grain films they feel that hardening reduces sensitivity. Specifically that the degree to which a film is hardened delays development, lowering sensitivity and soft gradation, the covering power of a developer is lowered because emulsion swelling is reduced. (Fuji terminology). Fuji also indicate the alternative is a film with larger inherent grain size, and they are striving to minimise grain size and increasing overall sensitivity.

That may well indicate why the Fuji Acros emulsion is deliberately softer and more prone to classic reticulation, yet also has almost no reciprocity failure (a property of the emulsion) and the best handling of low shadow detail of any B&W film. It's also therefore probable that the hardening of some of Kodak's B&W films may also be lowered as well but not by as much, possibly Tmax 400.

Then looking at classic reticulation when the surface of the emulsion crazes as it can't expand and swell sideways, there's usually significant migration of silver grain to the edges. What some of the other companies abstracts seem to indicate is that silver grain migration can also takes place to a lesser degree at lower parameters, which is why they talk of lowering reticulation. Fuji are more straight forward they speak in terms of graininess

This leads back to deviations in temperature controls in processing leading to increased graininess, micro-reticulation, grain clumping what ever we call it.

There are are references to grain clumping in books, magazines & the internet going back many years, Bernard J Suell mentions it in "Mastering Black and White Photography" 2003, he was also a writer for Darkroom & Creative Camera Techniques which carried an article in the late 80's testing for the effects with modern films, and demonstrating clearly that it occurred. There's no copy of the article available online & no-one seems to have that back issue. I have emailed Bernard Suess in case he can help, this i8s the relevant quote is from his book:he )

The temperature of all the solutions, including the wash water. Is critical be- cause of thc danger of reticulation. Reticulation occurs when the film emulsion cracks. The emulsion swells and softens during processing. The warmer the temperature the greater the swelling. If the temperature drops quickly, the surface of the emulsion contracts while below the surface it remains swelled. This causes small cracks to appear ln the surface. The cracks can appear as a pattern throughout the image when a print is made. Occasionally this pattern can make an interesting image; usually it`s a distraction. A mild form of reticulation, known as grain clumping, can also take place. This makes the image appear grainier and coarser than it normally would with proper processing. This is the major reason to constantly control the temperatures of all solutions.


Other education establishments back up John Davies comments that I quoted at the start, typically with similar comments about grain and temperatures:

Ideally, chemical solutions including wash water should be consistent in temperature, preferably at 68°F. Temperature variations of +/- 5°F are tolerated though grain size may be affected.

Ian
 
Ian;

Since gelatin and silver are bound together, if you get reticulation of gelatin, then the silver will follow. I have said earlier that reticulation is easier to get than clumping without reticulation. So, in this sense if gelatin actually parted down to the film base, due to severe reticulation, the silver would split on each side of the crack. That is rather obvious.

In an earlier post, you said that Kodak was researching this and I wondered if you had a reference. However, the temperature tolerances you post are in agreement with what I posted. And these seem to be wider than most of the posters here allow, yourself included. So how does this take place? That remains the question if there is no true reticulation.

In the case of Fuji, they are using hardenable polymers in their coatings. These do not bond to silver. Therefore, I would have to say that Fuji films may allow clumping to take place, especially if the films are softer than those of Kodak and Ilford. Kodak uses a proprietary method of getting dmax from difficult grains.

PE
 
Well, it seems to me that you almost agree with each other. Ian is saying that +/- 1 deg.C is reliable, and PE is saying +/- 2 deg.C. Correct me if I got it wrong, but these numbers are quite close.

However, with sloppy control, as just putting the tank under running water from tap, temperature may well change even 10 deg. C, because of the pressure change in cold/hot pipes caused by opening a tap somewhere else. That would be outside any range, given by Ian, PE, Kodak or Ilford. And it may happen occasionally with running water so that you don't even notice it, if you don't keep metering the temperature all the time. It may be two short shocks - to too hot/cold and then back to normal.

And, as said many times by different people, Fuji films seem to be more prone to this problem. If Ilford says +/- 5 deg.C, it's probably only for Ilford products. Fuji may be a bit different.
 
HRST;

The Kodak limits that I posted a reference to are actually a bit broader than either my suggestions or Ian's.

I keep a tight control on all steps of my process by using a Powers temp valve on my water supply, but I know that not everyone can do that.

PE
 

The suggestion is that the silver grain migration is not always the same as the gelatin swell which makes total sense when you think logically. If the gelatin swells at a moderate rate the silver grains stay evenly distributed, and the reverse as the gelatin shrinks and later dries. That's the ideal. However if the gelatin swells or shrinks too quickly due to a temperature shock then you get grain clumping, you have physical grains of silver that don't expand or contract like the gelatin. The end result is they won't necessarily return to the same position later instead clumping together.

Kodak's last Patent that I can think of with a reference to Reticulation is 6,153,362, filed 1999. Interestingly though Kodak make constant references in the 80's to "Reduction of Reticulation", so if it can be increased or reduced it's not just the straight forward case of reaching the pony where the gelatin crazes, somethings are happening prior to that.

The temperature tolerances I posted (not mine, a US University) of +/- 5° F had their rider that there could be increased grain. Personally I try to go for +/- 1° C but would not be unhappy if that went an extra half a degree off tolerance. That's roughly +/- 2° F

Ian
 
Photo Engineer said:
HRST;

The Kodak limits that I posted a reference to are actually a bit broader than either my suggestions or Ian's.

PE
Click to expand...

I think we miss a point that usually good books etc say the temperature changes must be gentle between baths/steps but can then drift to those much wider tolerances.

Ian
 
Ian;

That patent refers to reticulation in the presence of polymers + gelatin. Polymers are noted for reticulation and therefore this patent is related to solving that type of problem in color materials. There is no reference to "clumping" of silver grains. I have searched my references here and find no comments on grain clumping, just reticulation.

As for gradual changes in temperature, I agree with your comment, but the Kodak site only gives limits and does not address the issue of gradual changes from 18C to 25C for example. I have tried abrupt changes (by accident) when my Powers valve allows a fluctuation due to the house water supply and have no problem within the limits Kodak has posted.

PE
 
Kodak don't seem to use the term clumping, they seem to always say reticulation, but Fuji use graininess, as did Konica.

My take on the temperature issue within those tolerances +/- 5° F is more one of good results, no excessive grain, and then exceptional results where temperatures are kept very tightly under control. Having seen consistently excellent 35mm work (large prints) from a handful of photographers and spoken to them they all said there's was no magic bullet just very precise process control. When I did the same I got the same.

When I'm back in the UK I'll send you a strip of 120 Tmax 400 processed in Xtol with very excessive grain, I had my Leica with me that day & I was also shooting Tmax 400 (it's in one of the photo's of me hanging round my neck), my Leica shots were processed in the same replenished chemistry and aren't grainy. I was also shooting LF Tmax 100 - the images were of me for a magazine article. It must have been a cold day as I have a a jacket and my thickest sweater, so tap water temperatures would have been quite low probably < 10° C and the room with the stored stop bath and fix had no heating at all. I do remember being stunned that the photographer checked no temperatures except the developer. But I didn't notice until too late.

Ian
 
Greg, all my experience of increased grain, excessive or slight has been with shifts downwards not up.

I live in a climate where it's a far higher ambient temperature than 78° F (25.56°C) most of the year and tap water is close to 26°-27° C 9 months of the year. I get no issues as I process to the water temperature now.

If you want to cause excess graininess use water or stop-bath at close to 0°C, the colder the better, fix at your normal temperature then plunge into a very low water bath again. If that doesn't work then nothing will

Ian


 
Combining the observations from two different posts by Steve Smith and Sean Dougherty I would like to point to another possible problem. Steve Smith thought that the air that comes into the developing tank when changing liquids could cause a drop in temperature and Sean Dougherty had noticed that his films with course grain appeared mostly in wintertime. During cold winterdays you normally have a much lower relative air humidity indoors than during summerdays. A low relative air humidity will cause a much more rapid avoparation from a wet surface exposed to the air. This is the case even if the wet surface ( the film ) is at the same temperature as the air. I am sure many of you have experinced how much more you freeze when you step out of a shower into 20 deg C ( 68 F ) room temperature when it is 10 deg C below zero ( 14 F ) outdoors compared to when it is 20 deg C above zero outdoors. The more rapid evaporation from your skin ( the film in the first case ) requires more energy and subsequently lowers the temperature. If you change liquids quickly and thereby keep the time of air exposure to a minimum it should not be a big problem, but I think it is worth taking into consideration even if cold tap water may be a worse problem.
Thank you all of you for lots of film/developer information that I was not aware of before.
Karl-Gustaf
 
Ian Grant said:
. ...If you want to cause excess graininess use water or stop-bath at close to 0°C, the colder the better, fix at your normal temperature then plunge into a very low water bath again. If that doesn't work then nothing will. ...
Click to expand...


I wonder if an alcohol stop bath will also help to create the effect?
 
Well, I mentioned evaporative cooling in a previous post in a kidding manner as it is so remote of a chance that it probably would not have a significant effect. If so, film run in roller transports and dip and dunk processors would see this problem big time!

Alcohol might induce other problems. Good idea though. No smoking in the lab and don't work next to the gas dryer in your laundry room or your gas hot water heater.

PE
 

I like to measure the effect of evaporation cooling, but I've got 66% RH in my darkroom at the moment. A little more and it will rain in there!
 
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