Borax and Sodium Metaborate substitution

[Harold33]

In some solvent classic developers, it is possible to substitute Borax to Sodium Metaborate, e.g. Agfa-44 (Borax: 3gr.) and Agfa-44M (Sodium Metaborate: 2gr.) [BTW, Agfa 44 and Agfa-Ansco 17 are the same thing].
The Borax version is supposed to develop more slowly and to give a finer grain than the Sodium Metaborate version.

So, my question is: is it possible to generalize this equivalence for a given pH (1 gr. Borax = 0,66 gr. Metaborate) or is it necessary to ajust something ?

My question is about the (possible) equivalence ot the two component, not about the way to obtain Metaborate from Borax (as discussed here: (there was a url link here which no longer exists))

Best regards,

 

[Rudeofus]

Sodium Metaborate contains more Sodium ions per Borate ion, and as a result is more alkaline. Therefore you can't really substitute one for the other and expect similar results. Agfa-44 and Agfa-44M are effectively two different developers that happen to share some parts of their recipe.

 

[Ian Grant]

Sodium Metaborate contains more Sodium ions per Borate ion, and as a result is more alkaline. Therefore you can't really substitute one for the other and expect similar results. Agfa-44 and Agfa-44M are effectively two different developers that happen to share some parts of their recipe.

You're muddling Agfa Ansco 17 & 17M with the German Agfa (Orwo) 44 formula), while the US Agfa Ansco/GAF 17 formula is identical to Agfa 44 aside from Kodak Sodium Metaborate wasn't used in European formulae and there was never an Agfa 44M

In addition Agfa Ansco 17M was identical to Agfa Ansco 17 apart from using Metaborate instead of Borax, Kodak published DK76 which substituted 2g Sodium Metaborate for 2g Borax.

Kodak took Wellington Borax MQ developer and evolved it in a few ways one was D76 others were forerunners of DK50 and DK61a but with Borax.

Ian

 

[Rudeofus]

You're muddling Agfa Ansco 17 & 17M with the German Agfa (Orwo) 44 formula), while the US Agfa Ansco/GAF 17 formula is identical to Agfa 44 aside from Kodak Sodium Metaborate wasn't used in European formulae and there was never an Agfa 44M

I didn't invent this mud but took it from the OP at face value. Since I haven't used Metol based film developers in ages, I'm not well versed in these ancient formulas.


@Michael: there will never be a meaningful linear conversion between two alkalis except in very special cases, and Borax/Metaborate is certainly not one of them. Even with Metaborate kept constant at 1 g/l you can't find a quantity of Borax that will yield equivalent pH and buffering regardless of what else is in the mix. These conversion factors were useful when accurate pH meters were completely out of the reach of amateurs, luckily these times are behind us.

 

[Ian Grant]

I didn't invent this mud but took it from the OP at face value. Since I haven't used Metol based film developers in ages, I'm not well versed in these ancient formulas..

Apologies I hadn't spotted the OP had made the mistake first. It gets confusing because Agfa Ansco used different numbers to the parent Agfa company in Germany and only a very small number of formulae were made by both companies.

Ian