d23 and d72 homebrewed (fallout?)

[Keith Tapscott.]

The current msds for D-76 shows pentasodium DTPA. Ilford use STPP in ID-11. For the photo-hobbyist, sodium hex should work fine.

 

[Photo Engineer]

Which represents a change from what I was familiar with.

Actually, to get back to my OP, Na2EDTA will work jus fine. It is rather inexpensive and easy to come by. It is not perfect, but it will do the job.

PE

 

[Keith Tapscott.]

Which represents a change from what I was familiar with.

Actually, to get back to my OP, Na2EDTA will work just fine. It is rather inexpensive and easy to come by. It is not perfect, but it will do the job.

PE

I am sure it will Ron.
Ilford seem to be using STPP in their powder developers and pentasodium DTPA in their liquid concentrates.
They don`t use EDTA for reasons in this link.

 

[Photo Engineer]

EDTA is not biodegradable but "EDTA is in such widespread use that it has emerged as a persistent organic pollutant. Its degradation entails conversion to ethylenediaminetriacetic acid, which then cyclizes" quoted from Wikipedia. So it is so prevalent that they have devised means to cope with it that are not draconian.

I agree with your comment, but due to our ability to cope with it in effluent and its low toxicity, I have to minimize its problems when compared to many other choices. It has so many medicinal uses that it can hardly be shut out of use totally.

PE