Cleaning negatives in sodium bicarbonate solution

[Edimilson]

Hello!

I read in a book that in order to clean negatives it's possible to bathe them for 10 to 15 minutes in a weak sodium bicarbonate solution. But the author did not mention what concentration can be considered a "weak" solution. Can anyone help me?
Looking for info on the net regarding sodium bicarbonate was useless. I could only find recipes for developers containing sodium carbonate.

Thank you!

 

[Michel Hardy-Vallée]

Cf. the table here: (there was a url link here which no longer exists)

I suppose you could calculate the necessary strength of the solution by using a formula with sodium carbonate and multiplying by the requisite factor.

 

[Edimilson]

Thank you! I'll do the math.

 

[Photo Engineer]

This does not sound like a very good idea to me.

I have never seen such a recommendation. Usually, one cleans film with one of the common film cleaners.

PE

 

[Michel Hardy-Vallée]

Oh wait a minute, I thought you meant "fixer cleaning" by "cleaning." PE's post makes me realize that you meant instead "dirt cleaning" which is not at all what the data I have posted is for.

 

[Edimilson]

Oh, that's a pity. I found this piece of information in a book published in Brazil by a Millard Schisler (I don't think there's an English translation). On page 134 it says (I'm translating here): "To remove grease [I´m not sure this is the correct word here] and dirt, Kodak recommends that the negative be immersed in a weak sodium bicarbonate solution for 10 to 15 minutes. The negative must be gently rubbed with a piece of cotton soaked in the same solution".
Naturally I have no idea where the author picked this recommendation supposedly made by Kodak. Perhaps it's some kind of mistake. This book contains, otherwise, very solid and detailed information on all aspects of black and white photography.

 

[Photo Engineer]

Kodak sells an organic solvent based film cleaner for this purpose.

I don't think bicarbonate can remove grease easily from film. Alkali can dissolve animal or plant based greases and oils by chemical reaction, but generally cannot attack petroleum based oils.

PE