Milky Residue on Film

Photo Engineer · Apr 13, 2007

After re-reading Ryuji's comment and Bill Troops comment I felt moved to make a comment on buffering.

It is not widely known, but the various thiosulfate salts are pretty good buffers themselves in the range of 6.5 to 7.5. This is why Kodak color fixes work so well in this range even with stop baths. Ryuji is apparently unaware of this fact. Bill is, as I told him 2 years ago in person at the Formulary where we first discussed TF-4 and TF-3. The buffer capacity of both TF-4 and Ryuji's fix may come, to a great extent, from the thiosulfate ion and nothing more exotic than that. Bill Troop's TF-4 has a lot of EXTRA buffer capacity.

TEA, used in Ryuji's fix, is a rather poor buffer at low concentration and at high concentration it interferes with fixing activity. It slows things down by as much as 50% depending on concentration of the ingredients. He may have other buffers present, that is not the question here. It is irrelevant. If buffering is supplied by thiosufate, then the issue is moot.

As I said, I don't know the TF-4 formula but I have used it with acid stop baths including my own 2% acetic acid and Kodak Indicator Stop. It works well for me, so when it fails I want to find the reason. I would like to work with you Sandy to find the cause of the problem as I have a whole series of developer and fixer formulas in my notebook that I'm working on. I'm very interested in any potential problems.

I would very much like to get to the root of this problem, as I have never seen it.

In any event, I see a problem. I see words from one person with no proof, and I have seen proof of another persons words from my own work. So, I really do want to find the root cause of this. This is not meant to be a criticism in any way of any of the sides in this matter. TF-4 works for me. It has a long history of working. Lets find out what is going on here before we make accusations or claims.

Sandy, if I can help, contact me.

PE

Photo Engineer · Apr 13, 2007

KODAK SOLD SEVERAL ALKALINE FIXES. How many times must I repeat that!

It is not new. They sold both B&W and color alkaline fixes for years and they were both successful.

PE

Ryuji · Apr 13, 2007

sanking said:
I have seen dichroic fog in the past and generally associate it with a kind of rainbow effect. The milky residue I saw in this case was different in that it was merely bluish, not rainbow like, and seemed to be rather thick.

Sandy, I tried to explain this in my previous post but apparently it wasn't fully understood. The name dichroic fog came because of how it often looks (surface phenomena) but the same mechanism (formation of extremely fine silver particles) can take a number of other appearances. It can sometimes look oily sheen, sometimes single color stain, etc. When I suggested the possibility, I said "a variation of dichroic fog" to broadly include stains resulting from fine silver particle formation, and I didn't mean a particular way dichroic fog can look. Please read my previous post again.

Of course, to test whether you got a variant of silver stain or not, the easiest way is to clip a section of the stained film and apply a very dilute bleach (ferricyanide will do) and refix. If it goes away, it's probably silver stain. If not, it may be calcium or magnesium deposition. These can be easily removed by EDTA solution.

Photo Engineer · Apr 13, 2007

Dichroic fog is not removed easily by refixing. If the milky residue is removed by re-fixing it can be either silver halide or borate salts precipitated by hard water. I believe Sandy said the residue was removed by re-fixing. This suggests it was not dichroic fog.

Only a retained silver test on the film will conclusively prove if it was dichroic fog or retained silver halide, or borate salts or something else entirely.

PE

sanking · Apr 13, 2007

Photo Engineer said:
Dichroic fog is not removed easily by refixing. If the milky residue is removed by re-fixing it can be either silver halide or borate salts precipitated by hard water. I believe Sandy said the residue was removed by re-fixing. This suggests it was not dichroic fog.

Only a retained silver test on the film will conclusively prove if it was dichroic fog or retained silver halide, or borate salts or something else entirely.

PE

Ron,

I did indeed write that the residue was removed by re-fixing because that was my first impression. However, after the re-fixed negatives dried I had a closer look at them and some of the residue was still there. I then soaked the negatives for about ten minutes and wiped off the residue with a sponge.

Sandy

Photo Engineer · Apr 13, 2007

Sandy;

This indicates a salt problem with extremely hard water then. You probably had a Calcium Borate precipitate. Did you mix everything with DW? Is your water hard?

Ron

sanking · Apr 13, 2007

Ryuji,

I did read your previous post and I am not disputing the fact that dichroic fog can have different looks depending on cause. I simply remarked to Bill Troop that the dichroic fog I have seen in the past had the rainbow look. The bluish milky residue in this case could also be dichroic fog, but if so it is a kind I have not seen in the past.

Unfortuantely I have wiped all of the negatives clean at this point with a sponge so I will have to repeat the development procedures to test some of the solutions that you and others have suggested.

Sandy

Ryuji said:
Sandy, I tried to explain this in my previous post but apparently it wasn't fully understood. The name dichroic fog came because of how it often looks (surface phenomena) but the same mechanism (formation of extremely fine silver particles) can take a number of other appearances. It can sometimes look oily sheen, sometimes single color stain, etc. When I suggested the possibility, I said "a variation of dichroic fog" to broadly include stains resulting from fine silver particle formation, and I didn't mean a particular way dichroic fog can look. Please read my previous post again.

Of course, to test whether you got a variant of silver stain or not, the easiest way is to clip a section of the stained film and apply a very dilute bleach (ferricyanide will do) and refix. If it goes away, it's probably silver stain. If not, it may be calcium or magnesium deposition. These can be easily removed by EDTA solution.

Photo Engineer · Apr 13, 2007

Sandy;

Dichroic fog cannot be 'wiped off' as it is inside the gelatin, but precipitates can be wiped from the surface.

If there is any residue, a bath in neutral pH EDTA can remove it.

Ron

sanking · Apr 13, 2007

Photo Engineer said:
Sandy;

This indicates a salt problem with extremely hard water then. You probably had a Calcium Borate precipitate. Did you mix everything with DW? Is your water hard?

Ron

Ron,

Yes, I mixed everything with tap water, and it is very hard right now. I have measured the tap water in my house many times in the past and it has always been around pH 7.1. Right now, though, it is measuring pH 5.3, and checked this with both a meter and pH strips. I mixed the developer with this tap water, and also the second batch of TF-3. The first batch of TF-4 was mixed a few days ago and I don't know what the pH of the water was at that time.

I did notice that when I measured the pH of the working fixers they were just at pH 8.1, whereas in the past I remember TF-3 and TF-4 working at closer to pH 9.0?

So what would be the solution? Would adding some Calgon help?

Sandy

Photo Engineer · Apr 13, 2007

I think that the problem is Calcium Borate then, caused by extremely hard and acidic water. Lets pursue this a bit if you wish. I'll be glad to help offline and we can give our results here in a later post.

Ron

sanking · Apr 13, 2007

Photo Engineer said:
Sandy;

Dichroic fog cannot be 'wiped off' as it is inside the gelatin, but precipitates can be wiped from the surface.

If there is any residue, a bath in neutral pH EDTA can remove it.

Ron

Ron,

If that is the case the residue was definitely not dichroic fog because it wiped right off. It was on the emulsion side, by the way, not on the base at all.

Sandy

Photo Engineer · Apr 13, 2007

Well, that is to be expected. The highest concentration of fix is on the emulsion side. But, I"m still guessing without doing the experiment. The best guess is demolished in the face of experiment. Dichroic fog is silver metal and is difficult to wipe off. If it were easy, then all of the problems reported with it in the literature would have been obviated by one PecPad.

Ron

donbga · Apr 13, 2007

sanking said:
Ron,

If that is the case the residue was definitely not dichroic fog because it wiped right off. It was on the emulsion side, by the way, not on the base at all.

Sandy

This week I've had exactly the same problems as Sandy describes only the milky blue metallic sheen does not easily wipe off for me.

Doug Webb · Apr 14, 2007

The directions on TF4 indicate that distilled water produces the best results. I have had problems similar to yours in the past, and a number of other problems, that I thought were the result of changes in the tap water. Of course I could be wrong about my conclusion, but I have had no problems when using distilled water. I found out through my experience in attempting to keep tropical and salt water fish in an aquarium that the water that comes through the tap does not even approximate stability in terms of PH, hardness, level of contaminates of all kinds, or level of water treatment agents.

billtroop · Apr 14, 2007

"Sandy, I tried to explain this in my previous post but apparently it wasn't fully understood. The name dichroic fog came because of how it often looks (surface phenomena) but the same mechanism (formation of extremely fine silver particles) can take a number of other appearances. It can sometimes look oily sheen, sometimes single color stain, etc. When I suggested the possibility, I said "a variation of dichroic fog" to broadly include stains resulting from fine silver particle formation, and I didn't mean a particular way dichroic fog can look. Please read my previous post again."

Ryuji, this is complete nonsense. You are making it up as you go along. There is absolutely no basis in the photographic literature for what you are saying. You really must make more of an effort to get your elementary photographic terminology straight before you pose as a distinguished expert on the Internet. Dichroic fog can NEVER refer to a 'single color stain' as you declare. Dichroic fog always shows at least two colors. That is why it is called 'dichroic'. The word comes from the Greek for TWO COLORED. What sense would it make to denominate a stain of one color with a word that means two-colored?

In photography, one traditional definition is that the negative will have different colors depending on whether it is viewed by transmitted or reflected light, i.e., whether you lay it on a surface or hold it up to a lamp. There is no possibility of ambiguity here. A stain is ONLY called dichroic when two colors are easily visible. I think this is bedrock elementary photographic knowledge, contained in every elementary textbook?

Photo Engineer · Apr 14, 2007

Well, the fact that this was a single color rather than multicolored was a clue to me. I did not want to criticize anothers interpretation of the problem, but Bill Troop is correct. Dichroic fog is multicolored, described by some as looking like a moire pattern on the film, and since it is silver metal deposited througout the gelatin matrix it is difficult to remove.

Colloidal sulfur often behaves this way, but is white or yellow and is found throughout the film. The surface can be wiped clean of it, but you will see it often within the film itself.

This could also be a calcium salt of one of the absorber dyes or sensitizing dyes that precipitated in or on the coating. They are easily removed by rewashing or wiping the surface.

PE

billtroop · Apr 14, 2007

Ron, isn't there a technique given by Crabtree et al in Photographic Solutions and Chemicals for removing such deposits in a stop bath? Bud Wilson once told me that he has never had customer problem with TF-4 that he couldn't resolve by having the customer use distilled/deionized/demineralized water.

Photo Engineer · Apr 14, 2007

Bill;

I don't remember. I would have to do some research on that. Our work centered around trying to prevent it chemically, or removing it without harming the primary image. The latter is very difficult if you bleach, but that was the only method I k new of.

I'll see if I can find anything.

Ron

donbga · Apr 14, 2007

Photo Engineer said:
Bill;

I don't remember. I would have to do some research on that. Our work centered around trying to prevent it chemically, or removing it without harming the primary image. The latter is very difficult if you bleach, but that was the only method I k new of.

I'll see if I can find anything.

Ron

FYI, last night I processed two more sheets of film in Pyrocat-HD with EDTA disodium added to the developer - 10 g/liter. The film still had the milky blue metallic sheen and it doesn't wipe or rub off.

Just for the record I presoak the film for 5 minutes in tap water with a pinch of sodium carbonate. Semi-stand develop in a Unicolor drum, stop with indicator stop bath and fix with film strength rapid fixer.

Photo Engineer · Apr 14, 2007

Ummm, what fixer did you use?

And, the EDTA should be in the fixer!

PE

sanking · Apr 14, 2007

donbga said:
FYI, last night I processed two more sheets of film in Pyrocat-HD with EDTA disodium added to the developer - 10 g/liter. The film still had the milky blue metallic sheen and it doesn't wipe or rub off.

Just for the record I presoak the film for 5 minutes in tap water with a pinch of sodium carbonate. Semi-stand develop in a Unicolor drum, stop with indicator stop bath and fix with film strength rapid fixer.

Don,

Sorry, I did not realize that you planned to add the EDTA to the developer or I would definitely have advised against that. The working Pyrocat-HD solution depends on a fairly high pH (around 10.9 or so) and I am almost certain that adding 10 grams of disodium EDTA per liter of working solution would drop the energy of the developer a lot.

Sandy

Photo Engineer · Apr 14, 2007

I checked Crabtree, as per Bill Troop.

There is a definition of it (red / green depending on reflected or transmitted light) and no mention of how to remove it.

Crabtree states that it is caused by silver halide solvent in the developer or insufficient stop or rinse before an alkaline fix bath. This (whatever it is) does not appear to be dichroic fog.

Ryuji does indeed appear to have erred, as dichroic fog is not removable by wiping and is not blue or white material on the surface.

PE

donbga · Apr 14, 2007

sanking said:
Don,

Sorry, I did not realize that you planned to add the EDTA to the developer or I would definitely have advised against that. The working Pyrocat-HD solution depends on a fairly high pH (around 10.9 or so) and I am almost certain that adding 10 grams of disodium EDTA per liter of working solution would drop the energy of the developer a lot.

Sandy

No problem, though I did think it odd putting EDTA into the developer and the thought that the pH of the developer would be radically affected did cross my mind. As I said in my PM the film did look under developed.

The fixer I use is is a no name product, Photafix, manufactured/distributed by Allied Photo Products Co.

Photo Engineer · Apr 14, 2007

EDTA or an equivalent is added to developers. Kodak has used Quadrofos and Calgon. However, the pH is readusted after addition.

PE

donbga · Apr 14, 2007

Photo Engineer said:
EDTA or an equivalent is added to developers. Kodak has used Quadrofos and Calgon. However, the pH is readusted after addition.

PE

So which is it Ron, put the EDTA in the developer or the fixer to eliminate the blue silvery film?

Milky Residue on Film

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