Milky Residue on Film

[sanking]

Given the fact that so much expert knowledge and opinion was offered toward the solution of my problem I was optimistic that some testing might get to the bottom of the matter.

Several solutions were offered. However, in order to try any of them I needed to duplicate the milky residue on some more negatives since I had previously wiped the first batch with a sponge.

So I set out today to replicate the results. Alas, I could not. Using the same film, developer, acetic stop bath and TF-4 fixer, and the same development procedures, I was absolutely unable to reproduce even a hint of a milky residue on the film. I did check the pH of the tap water again, which I used to mix the developer (the acetic acid bath and fixer were already mixed and same as I used before), and note that it was pH 6.5, still acidic but much less so than when I tested it a couple of days ago.

At this point I am inclined to believe that PE is most likely correct in that the residue was some kind of precipitate that formed on the film as the result of specific combination of hard water and low pH. In that sense, the recommendations to use distilled water for all solutions makes sense. In any event, I will be much more alert to potential problems caused by inconsistencies in the quality of tap water.


Sandy King

 

[dancqu]

So I set out today to replicate the results.
Alas, I could not. Using the same ... Sandy King

I suppose it goes without saying that the exact same
everything will produce exact same results. So, not each
and everything of the two runs was exactly the same.

Perhaps some variables have been allowed to change.
Were any considered non-consequential? Dan

 

[sanking]

I suppose it goes without saying that the exact same
everything will produce exact same results. So, not each
and everything of the two runs was exactly the same.

Perhaps some variables have been allowed to change.
Were any considered non-consequential? Dan

There were some variables that I considered non-consequential.

1. The original film was 12X20 devleoped with rotary processing in a 16X20drum. The second tests was of 4X5 film cut from the same film, developed in tubes. The same amount of developer per square inch of film was used.

2. The stop and fixing baths were carried out in the 16X20 drum. The smaller film in tubes was taken directly to a tray containing the stop bath, and the film was then removed from the tubes and fixed in a separate tray.

The above is standard procedure for me, i.e. tests are done in small tubes and the actual film is develope in larger drums. This has never lead to the milky residue before.

The only other variable of which I am aware of is that the water that was used to mix the developer for the first run was quite a bit more acidic than that used for the second run.

Sandy

 

[Photo Engineer]

Sandy;

Whatever caused the higher acidity of the water might have done you in the last time. There might have been more salts available in the more acidic water. Less acidic water tends to carry less metals such as calcium. Cities hereabouts try to keep water more alkaline for that reason, I think.

If it is the acidity, then even a rinse in that water might have formed a scum in any fixer. Calcium Alum is not very soluable if you go into KRLF with hardner. That is why most developers and fixers nowdays contain Quadrofos or EDTA. They used to use Calgon until that company changed its formula to something less effective for films and papers.

Disodium EDTA in the fix should eliminate the problem, or use DW to mix the fix or dilute it. And, rinse the film in DW before washing and after washing before the photo flo. The photo flo should be mixed in DW.

However, the scum should have been there if the solutions were mixed with that water unless the scum only formed in the wash water, but in that case, you should have seen some scum form in the fixer itself when diluting it.

This still remains a bit of a puzzle to me.

PE

 

[Keith Tapscott.]

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

PE

Is that the reason that it is usually recommended to add a sequestrating agent first before dissolving the main components?
I have sodium hexametaphosphate of which I usually add a `pinch` to the water first.

 

[Photo Engineer]

Sodium Hexametaphosphate is among the orignal ingredients to Calgon. Yes, you could use that. Disodium EDTA is probably better.

A pinch in the developer and in the fix won't hurt. Usually, I use between 2 - 5 grams or 5 - 10 grams for more difficult cases in each liter of developer or stop or blix.

Be careful that you do not alter the pH whatever you choose to add.

PE