Cleaning negatives with solution of sodium carbonate?

[phil146]

I have had many problems with dried on dust on my negatives and came across a suggestion in a old Kodak Darkroom Dataguide. It suggested to use a dilute solution of sodium carbonate (not bicarbonate), which is washing soda, to soak and clean duty negatives. I have tried it on some old negatives-doesn't seem to leave any residue but I haven't gotten great results yet. Still experimenting with it. Has anyone used this before? Any suggestions greatly appreciated!
Phil

 

[Vaughn]

My thoughts (not experience);

Sodium carbonate will soften gelatin...I have used it to do so in carbon printing. I do not know if it will effectively soften gelatin that has been significantly hardened with modern hardeners (in fixers or now incorperated into the emulsions when the film was made). Ilford puts hardening agents in their emulsions and the emulsion hardens as it dries.

So the sodium carbonate may not be as effective as it once was (age of your Data guide?) in softening the emulsion of the film and allowing it to release stuff that got attached to it as the emulsion dried.

 

[phil146]

Hi Vaughn,
Thanks for commenting. My Dataguide is a 1988 version but I was hoping that the sodium carbonate tip might still work. After trying it on a few negatives, it looks like it does. Had to soak one for several hours but it looks clean. No obvious residue on the film. Pleasantly surprised.
Phil

 

[Loren Sattler]

I have the same problem with some negatives….small particles of debris attached to the non emulsion side of a negative. I will get this on occasion despite using photo flo with distilled water for the final rinse. It becomes very problematic with thin 35mm negatives when enlarged to 8 x 10 or larger……many white spots on the print. Currently I have a very nice negative to print with this issue. I tried some old Edwal film cleaner. It helped some, but did not totally correct the problem. Should I rewash and rinse again with photo flo, or try something else like the sodium carbonate idea mentioned here? This stuff does not come off the negative easily.

 

[Vaughn]

Good to hear that it worked for you, Phil! Sounds like the hardening is over-come by the Sodium carbonate over time. Just be aware that the emulsion will be soft, so care must be taken until the neg has been re-washed and dried.

 

[Tom1956]

I mix up some photo-flo solution somewhat stronger, in a tray and drop the negatives in and lightly swish the faces of the film with a soft brush. Then wash, and photo-flo again normally

 

[phil146]

Vaughn,-still experimenting with this but I'm hopeful I can finally produce prints that are dust spot free. This has always plagued me as a printer. Also, always used RC paper but am about to try fiber, hoping that will be easier to spot if necessary.

Loren-like you, I have tried distilled water, in case my well water is the problem, but not much difference. I haven't tried to print any negative after cleaning with sodium carbonate and only used it on some unimportant ones. I mixed about 1 Tbsp (15ml) of washing soda with about 250 ml water-just a guess about an effective concentration. On close examination, they look pretty clean. Have to get brave and try it on some good negatives.

Tom-thanks for the suggestion. Have been reluctant to use anything to rub or brush my negs. (Tried PEC pads and Delta Film Cleaner, too.) Any special type of brush? Doesn't produce any scratches?

Thanks everyone,
Phil

 

[Tom1956]

Vaughn,-still experimenting with this but I'm hopeful I can finally produce prints that are dust spot free. This has always plagued me as a printer. Also, always used RC paper but am about to try fiber, hoping that will be easier to spot if necessary.

Loren-like you, I have tried distilled water, in case my well water is the problem, but not much difference. I haven't tried to print any negative after cleaning with sodium carbonate and only used it on some unimportant ones. I mixed about 1 Tbsp (15ml) of washing soda with about 250 ml water-just a guess about an effective concentration. On close examination, they look pretty clean. Have to get brave and try it on some good negatives.

Tom-thanks for the suggestion. Have been reluctant to use anything to rub or brush my negs. (Tried PEC pads and Delta Film Cleaner, too.) Any special type of brush? Doesn't produce any scratches?

Thanks everyone,
Phil

Just one of those high-quality little paint brushes. All I recall is the name of Windsor something on them. And I don't mean scrub the negative with it. I just mean lightly swab it with the brush, while it's the negative is submerged.

 

[phil146]

Thanks Tom. I'll pick one up and follow your suggestion. Good to have as many remedies as possible.

 

[cmacd123]

The motion picture folks sometimes just re-process the film as negative (colour or Black and white as needed - don't get them mixed up) as re-washing.

The H2409 set of manuals for ECP-2 (colour print) shows a re-washing sequence using 2 minutes in "Pre-bath PB-6" a two minute wash and ten seconds in a final rinse FR-1 Only problem is I am not sure where they gives the formulas for those.

 

[phil146]

Hi Charles,
Thanks for the comments about rewashing. Not sure about the chemicals you've mentioned but I will be trying to rewash my problem negs, with PhotoFlo and a soft brush, following Toms' suggestion, and/or the sodium carbonate solution.
Phil