washing negatives - Does the fixer leach out?

[dancqu]

Second paragraph, I must have meant; ... acid or alkaline fixer
rather than wash water. Dan

 

[dancqu]

Last but not least, a German guy (I think he is German) had
done a nice test job on washing. He confirms the Ilford washing
procedure. You'll find the results here :
http://www.geocities.com/ResearchTriangle/Thinktank/5693/photogra.html

An interesting read. He uses the HT-1 test. That is a
test using potassium permanganate as an indicator of
the presence of thiosulfate in the wash water.

An aside by the author indicated the influence of wash
water temperature on the effectiveness of the wash. You
may have caught that. A few degrees warmer did help rid
the film of additional thiosulfate. I always wash with
room temperature water. Dan

 

[mitch brown]

how would you use the ilford methoid with a staining developer which have a longer time to allow the stain to intensify?

 

[Monophoto]

Roger, you missed the bit about the fill and dump method being good exercise.

Dave -

That is true. The exercise quality is almost as good as repeatedly lifting a mug of beer.

 

[Ryuji]

That is true. The exercise quality is almost as good as repeatedly lifting a mug of beer.

Except that my Paterson tanks hold more than 3 US pints of washing water in them, and I can run two or three of them simultaneously

A better exercise may be to run around the city with an old Mamiya TLR.

 

[Ryuji]

An aside by the author indicated the influence of wash
water temperature on the effectiveness of the wash. You
may have caught that. A few degrees warmer did help rid
the film of additional thiosulfate. I always wash with
room temperature water.

If you use washing aid, the temperature of washing water is a non-issue.

The problem is that, like I wrote before, the limiting factor in washing is desorption, which has higher energy of activation than diffusion, and therefore it is more temperature-dependent than diffusion. However, washing aid strongly helps in the desorption process, and so the following wash water only have to deal with the diffusion process.

In my own tests using Silvergrain Clearfix and Clearwash, I could use Boston's very cold winter tap water to wash out residual fixer level to way below the archival standard, very rapidly.

 

[dslater]

Been busy. What does hca stand for? It stands for
hypo clearing agent; also known as wash aid. KHCA
is Kodak's version. There are many. Of the many on
the market by far the majority, perhaps all, are based
on one or two sulfites; sodium and or ammonium.

I think all are of the one-size-fits-all design. I've not
read of any hca that wouldn't do for film or paper, acid
or alkaline wash water. For the most part the use of a
wash aid is confined to fiber base papers for which it
is much recommended. It's use follows fixing and a
rinse may or may not immediately precede. Dan

Hi Dan,
Thanks for the reply - I am familiar with hypo-clearing agent - I just wasn't able to make the connection with the initials hca

Dan

 

[dancqu]

I don't mean to intrigue you unnecessarily but if you
wash fixed film in strong KBr solution there will be some
insoluble silver thiosulfate salt, often called "B-salt"
in photographic chemistry.

Bill Troop has said that potassium should not be allowed
to contaminate the fixer. Dr. M. J. Gudzinowicz allows for
some small tolerance. Why is so little potassium allowed?
Because the potassium salt of other wise soluble silver
thiosulfate complexes is very little soluble.

The sodium and ammonium di and tri thiosulfate silver
complexes are soluble. What of calcium, iron, manganese,
and others. I suppose hidden away on some dusty shelf are
the solubilities of argentous thiosulfate salts other than the
two found in photography. For that matter who knows the
solubilities of the sodium or the ammonium? Dan

 

[shicks5319]

Measuring fix residual

This thread has been a good read.

I have used the Ilford wash method for roll film and a slightly different version for sheet film where I let the film sit in the water for several minutes between dumps.

Is there a reasonably non technical way to actually measure for any residual of fix in washed film? It would be great to have some way to test the effectiveness of any wash routine.

Thanks for your thoughts.

 

[Michel Hardy-Vallée]

I had never heard that - why would pure water take longer to wash?

Tap water contains some components like sodium bicarbonate who behave in a manner significant to hypoclearing agents. Distilled water does not have these.

Cf. the work quoted in Haist: (there was a url link here which no longer exists)

EDIT: Oh, I noticed that Roger quoted a similar passage from Haist as well. Guess we are kindred readers!

 

[Ryuji]

Bill Troop has said that potassium should not be allowed
to contaminate the fixer. Dr. M. J. Gudzinowicz allows for
some small tolerance. Why is so little potassium allowed?
Because the potassium salt of other wise soluble silver
thiosulfate complexes is very little soluble.

In reality, it doesn't matter. None of the common fixer bath contained potassium, and none of the common stop baths contain potassium today. Solubility of all sorts of silver thiosulfate complexes is well studied and the data is available for potassium salt as well. Solubility of AgX in potassium thiosulfate was studied, although potassium thiosulfate is very uncommon and rarely supplied in technical, photographic or purified grade. The research by Hirsch of Kodak Harrow lab is pretty well known. It's also that in a sodium or ammonium thiosulfate fixer, presence of some potassium salt has little harm, and there is even a patent (US Patent 5358832) claiming that combination of potssium and sodium thiosulfate provides faster fixing than sodium thiosulfate alone, although this technology hasn't been used commercially (and I am not certain whether this invention is useful in practica).

The sodium and ammonium di and tri thiosulfate silver
complexes are soluble. What of calcium, iron, manganese,
and others. I suppose hidden away on some dusty shelf are
the solubilities of argentous thiosulfate salts other than the
two found in photography. For that matter who knows the
solubilities of the sodium or the ammonium? Dan

You are free to test your theories or make more rational arguments based on known facts, but I am afraid to say that making practical recommendations for others based on imagination is not a very responsible thing to do...

 

[Ryuji]

Tap water contains some components like sodium bicarbonate who behave in a manner significant to hypoclearing agents. Distilled water does not have these.

Cf. the work quoted in Haist: (there was a url link here which no longer exists)

EDIT: Oh, I noticed that Roger quoted a similar passage from Haist as well. Guess we are kindred readers!

I understand people cite out of Haist's book because it's a convenient book, but the original effort was due to Green and Levenson at Kodak Harrow Lab and people should use attention to credit the right persons.

 

[Michel Hardy-Vallée]

I understand people cite out of Haist's book because it's a convenient book, but the original effort was due to Green and Levenson at Kodak Harrow Lab and people should use attention to credit the right persons.

Yes, I know. That's why I called it "the work quoted in Haist". Note that I give proper credit to Levenson in my linked post that contains the actual data. I'm doing enough academic work myself to know what citing means, so please don't misconstrue what I'm writing by reading it badly.

 

[Saganich]

There is one method I've seen which uses the 5, 10, 20, 30, then five 5 minute soaks, then 5, 10, 20, 30. I also read somewhere that if you sling out the water in the reels and in the tank cap between agitations the whole process becomes more efficient.

 

[Michael W]

I noticed a couple of posts that refer to fix with hardener as a problematic thing. I checked, & the facility where I do my processing has Kodak rapid fix with hardener. Why do some people think this fix is not so good?

 

[Roger Hicks]

I noticed a couple of posts that refer to fix with hardener as a problematic thing. I checked, & the facility where I do my processing has Kodak rapid fix with hardener. Why do some people think this fix is not so good?

It ENORMOUSLY increases wash time, wasting water to no end.

Cheers,

R.

 

[Photo Engineer]

Guys;

I've been following this and doing some 'research' on my own and with the help of others. For an example, try here: http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00Arzw

This shows you how long people have been thinking of this on the internet and how long before this referenced thread the subject was considered by Kodak and Ilford. We worked on this at Kodak for over 50 years.

Simplifying, fixing is a 2 step process including diffusion inward and outward of the silver hypo complexes and also the complexation reaction(s) themselves which can form anywhere from 5 or so sodium silver thiosulfate complexes. If ammonium ion is present the number of complexes increases drastically.

Along the way in all of the research on this subject, it has been discovered that potassium ion above trace amounts tends to poison the fixing reaction as described by Mees.

Washing is basically a two step process involving diffusion inward of fresh water and diffusion outward of water + complex salts. Agitation and time are both needed to effect this process.

Both of these steps (fixing and washing) change the swell of the gelatin and therefore the interstitial size and path in the gelatin matrix through which the materials must diffuse and so the pH, ionic strength and type of gelatin are important as are the quantity of silver and gelatin coated. Hardener is a very important factor as well. In paper, the FB vs RC issue is also raised.

Now, to make one point, at 68 degrees F (20 deg C), it takes about 20" for a front of moving chemistry to diffuse inward, and a similar amount of time to diffuse outward. Once an equillibrium of chemistry forms at the surface, diffusion slows down due to the skin of 'chemistry' in water that is to be found on the surface of the washing film or paper. Therefore, residence time of 40" is an average figure that we used for the first emergence of spent chemistry into wash water from the film. (NOTE: Average - it varies with film, gelatin, pH and etc)

This exchange slows down at that point unless there is agitation, so still water will slow washing just as still developer slows development and you can get hypo silver complex drag just as you get bromide drag in a developer.

For good exchange, I must disagree with those who say that they go with 5 quick changes of water or those that say they use no agitation, unless each exchange is accompanied by good agitation or long residence time or both.

Just filling the processing tank and covering the film with a fresh change of water may take 20 - 40" which is hardly enough time for diffusion inward and outward and exchange of water for water + salts, and therefore hardly enough time to wash the film properly.

I'm afraid that though the Ilford results may work, they allow insufficient safety factor for all types of film and for all types of fixer and wash waters. I would go with the GIP Levinson data which suggests a 5' residence time (with agitation) between each changeover.

And, the use of the silver nitrate test for hypo and silver sulfide for silver is a good pairing of tests to check the quality of the wash.

Additional wash aids are a waste of time and money IMHO, and also add an extra step to the process as well as extra chemicals in the effluent you produce.

PE

 

[Ryuji]

It ENORMOUSLY increases wash time, wasting water to no end.

I agree, for manual processing of film and prints, hardener is unnecessary and counterproductive. Hardening does not offer any useful effect once the material is dried, and most modern material don't require hardener in manual processing.

HOWEVER, there is persistent misconception that hardener reduces the risk of scratch or other mechanical damage to the film and paper while handling them (e.g. printing and filing). Some hardening fixer products advertise them with such a misconception, or have it printed on the label. It may be what people hope from the word hardener but it is not what it does and I feel that this point should be disseminated widely. (as well as the problems with overwashing as well)

 

[billtroop]

I agree, for manual processing of film and prints, hardener is unnecessary and counterproductive. Hardening does not offer any useful effect once the material is dried, and most modern material don't require hardener in manual processing.

HOWEVER, there is persistent misconception that hardener reduces the risk of scratch or other mechanical damage to the film and paper while handling them (e.g. printing and filing). Some hardening fixer products advertise them with such a misconception, or have it printed on the label. It may be what people hope from the word hardener but it is not what it does and I feel that this point should be disseminated widely. (as well as the problems with overwashing as well)

This is complete fantasy, again, from the person who recently informed us that dichroic fog has a single colour. (If that were the case, it would be called 'monochroic'.) Harold Russell described to me the primitive device that his team used to study the efficacy of the hardeners he was studying at Kodak at the time he was designing the classic Kodak fixers, such as F5, F6, etc., ad gloriam. It was a nail attached to a piece of wood that was drawn over the _dry_ film at calibrated tension. The index for hardening was the resistance of the dry film to scratches with this nail.

Roger's theories on no-wait rinsing, which I consider irresponsible to an extreme, were discussed, and debunked over two years ago here:

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00Arzw

Roger has yet to provide a shred of published evidence from any named, known scientist that a waiting period is not essential for a wide variety of reasons. G.I.P. Levenson was one of the senior scientists at Kodak, Harrow, a hghly respected figure in the industry with stacks of (peer-reviewed) publications and patents to his name. He was not an amateur or a flakey grad student, and his recommendations should be accorded due respect.

A footnote to the history of borate-aided anti sludging fixers is that Russell theorized, to me, that borates might be as effect for chrome alum fixers as they proved to be for potassium alum fixers in extending the sludge point. He had hoped to study this but other projects at Kodak prevented him -- for example, he was the director of the project, funded with, for that time unprecedented generosity, which led to the XoMat and Versamat machinery and processing chemicals. It was at that time that he came to advocate alkaline fixing, incidentally. It would be interesting, as a footnote to traditional photographic chemistry, if someone were to test Russell's idea, that the pH of the sludge point of chrome alum fixers could be raised by the addition of borate to the solution. When testing, the borate must be carefully titrated -- failure to do so is the reason why previous researchers did not make this valuable discovery.

 

[Photo Engineer]

Well, interesting Bill. I was referring to your post in that PN thread in which you cite the very items you bring up above.

Everything you have said about testing fixers with an 'abradometer' is correct. I used a modernized version myself many times. We used it to test the new hardener and also the alkaline hardener you refer to although we used formalin in the release version not alum.

Alum and zircotan hardening are actually carried over 'after the fact' when the material is dry but I hate to get into an argument anymore.

Zircotan has also been used in addition to alums. In these cases, we often refer to this as 'case hardening'. This term was used at EK to describe the hardness imparted by alums and zircotan among others which tends to put a very hard surface on a film or paper.

In the case of paper, it is extremely valuable for use to improve gloss in ferrotyping and was used in early fixes and in color print materials on FB support ("C" and "R" both used case hardeners in early processes and required drying first before ferrotyping to allow the case hardening to 'set', contrary to what Ryuji says above). It was also used in the Kodak CP-5 process which was the first 100F process.

It also makes the photographic material more subject to cracking when bent. Alums are less prone to causing this effect compared to zircotan, as it more or less hardens the coating throughout rather than just at the surface as found with zircotan).

I see that by avoiding an argument, I have helped perpetuate a myth.

One reason why Ryuji may believe as he does is the fact that alum hardening can be reversed under the right conditions and therefore you cannot see the effect. With simple experiments, you can draw an incorrect conclusion.

BTW, this reversal of hardening is discussed in Mees IIRC. I don't have my copy handy, but I do remember the experiments I ran myself and abradometer clearly.

PE

 

[dancqu]

This is complete fantasy, again, from the
person who recently informed us that dichroic
fog has a single colour.

Personally I thought Ryuji's Description of Dichroic Fog
more apt than some Dictionary's Definition of Dichroic.
Fog is a dictionary word but on another page. Dan

 

[Photo Engineer]

Hardening of gelatins

Here is a summary of effects when hardening gelatins for photographic use.

At the factory a coating can be left unhardened, hardened a little or hardened a lot. Hardening increases the melting point of gelatin, so unhardened coatings cannot be processed over 68 deg F or 20 deg C which is the native melting point of gelatin and is the origin of the process temperature of all B&W products.

Color, being so thick, required higher process temperatures in order to be done in a shorter time and therefore required more hardener, but B&W products with newer hardeners can be processed easily at 75 degrees F. This is because they are hardened a little, and this is done so as to allow the silver metal to burst out from the development site during development and form a dense silver image. Color, not being dependant on the density of silver, can and must be harder.

So, color films are hardened a lot.

There are many hardeners but there are basically 3 types of hardeners used commonly.

One type is a family of chemicals called alums. Chrome alum and Alum itself are examples of members of this family. Zircotan is another. They rely on metal salts that react with gelatin to cross link it via an ionic bond. This bond can be reversed and therefore the hardness can be lost. Some penetrate poorly and are used to harden the surface of a mateial or to tan it. Some are even used in leather tanning. Surface hardening is called 'case hardening'.

The second type is a family called aldehydes. Formaldehyde, Glyoxal and Glutaraldehyde are members of this family. They harden slowly and tend to fog emulsions. The continuing hardening of the film or paper and the growth in fog are the result of a process called 'afterhardening' and were the cause of bad keeping among older photo products. In a very rare conicidence that happens once in a lifetime, this effect is discussed on just about the same page in Mees and in volume I of Haist (about page 80 - amazing isn't it?). This type of hardening is very difficult to reverse. It is not an ionic bond, it is what is called a covalent bond.

The third type are the family of modern hardeners developed by Kodak, Fuji and Ilford.

No film is fully hardened, and therefore you can ADD hardness to the whole film or to the surface by using combinations of the first two types of hardeners. For example, you can soak a poorly hardened film in sodium sulfate at 100 g/l at the end of the process to reduce swell, and then if the solution contains an alum or an aldehyde, you can harden it more. If zircotan is added, the surface is hardened more than the interior.

Improper post hardening processing can reverse alum hardening and case hardening but cannot reverse aldehyde hardening.

In addition, adding hardeners all reduce swell or 'freeze' it at its current state, depending on hardening type or solution mix. This can change developer time (if it is a pre-hardener) or it can change fix or wash times depending on how it changes swell.

A poorly swollen film or over hardened film (or paper) processes more slowly than a swollen film or paper.

I hope this helps clarify things a bit. It is more complicated, but I have refrained from adding a lot of technobabble and extra details.

PE

 

[Photo Engineer]

Personally I thought Ryuji's Description of Dichroic Fog
more apt than some Dictionary's Definition of Dichroic.
Fog is a dictionary word but on another page. Dan

Dan;

Dichroic fog has been in use since the early days of photography when develpers contained ammonia and early photographers first saw their negatives take on a metallic green-red color. So, they called it dichroic (two color) fog (because the ammonia was causing silver development in non-image areas).

It was further found that addition of silver halide solvents to developers in general cause this type of fog and ammonia was abandoned. Finally, it was found that silver halide solvents were useful in making very fine grained images and thus Microdol and Microdol-X were formulated. But since they contained a silver halide solvent, they also contained a dichroic fog supressant.

For this, the inventor was granted a patent and the race was on to find solvents that did not cause dichroic fog or compunds that supressed its formation. Today we have both in our arsenals of chemistry to make better developers. By using one of them, I hope to come up with a new High Acutance developer.

I hope this helps your understanding of why two words widely separated in the dictionary became linked in the photographic science arena. It also explains why Bill Troop may want to point this out to us, because misuse of the term or misunderstanding of the term can lead us to the wrong solution to a problem.

In the case in point, it was not dichroic fog by the very description (to those who know) and could be wiped off the coating, which is not the case for dichroic fog.

PE

 

[Ryuji]

Personally I thought Ryuji's Description of Dichroic Fog more apt than some Dictionary's Definition of Dichroic.

I don't see posting from people in my ignore list, but I did describe dichroic fog usually looks with different colors depending on transmission or reflected light, and even at different angles in case of reflected light. I also described the same mechanism (silver stain; dichroic fog is a form of silver stain) can take other appearances, and does not require multiple colors. Please tell them to stop the nonsense.

 

[Photo Engineer]

In Sandy Kings original post in the thread in question, he described a problem with a milky blue residue on his film (ON not IN). Ryuji responded that it sounded like dichroic fog. Later on in the thread, Ryuji did say that dichroic implied two colors depending on how you looked at the film. These two answers were at odds with each other and were not an accurate response to Sandy's problem.

In no case is dichroic fog on the film surface, and it is never blue or white. It is green and red. So, it is easy to be confused by Ryuji's answers which go a bit wide of the mark in describing 'dichroism' and his lack precision for those trying to solve a problem and interpret the remarks of both the OP and the respondants.

It is doubly confusing when one of the participants is ignoring remarks by others.

It is easy to ignore remarks from those you disagree with or don't like for one reason or another, but then again, it tends to confuse us all. I think that this is what is happening here.

If Ryuji wishes to respond, he should use photographic terms in the sense that they were meant to be used, in the context of the question being answered, otherwise it leads to confusion and misinterpretation. If he wishes to respond in a meaningful manner to technical discussions, he would be well served not to ignore acknowledged experts such as Bill Troop. Perhaps he should not be ignoring me either.

In any event, Bill Troop's comments were based on the OP by Ryuji which was incorrect given the context.

PE