EDTA Solution Stability?

[Steve Hamley]

Folks,

In "The Book of Pyro", Hutchings describes the use of EDTA and gives a recommendation for a 1% solution in water.

My question is:

"Is the solution stable or does it need to be mixed fresh each time/developing session?"

Thanks, Steve

[Vaughn]

I hope it is -- I make up batches of it and use it months afterwards. My prints still clear.

I even sometimes save my relatively fresh last HCA/EDTA bath from one session and use it as my second bath in my next printing session (my first clearing bath is always Citric acid) -- which can be weeks later.

Vaughn

[Steve Hamley]

Vaughn,

Thanks for the reply. This solution is not used as a clearing agent, it's added to the developer to prevent mottling/streaking and for use in rotary processing - if this makes any difference.

I use it in the clearing agent in platinum printing for a long time too, but there's also other things in there too, like HCA or sodium sulfite, which is itself a preservative. The developer solution would not have these other chemicals present.

Cheers, Steve

[Vaughn]

I make up the EDTA and store it separate with no problems.

[Drew Wiley]

It doesn't take much. Just a few drops; and most films don't need it anyway. I mixed
up a litre of 1% EDTA about five years ago and it still seems fine.

[Dan Fromm]

A saturated solution of Sodium EDTA in DMSO is used to preserve tissue samples and the DNA in them. It is supposed to be good indefinitely.

[Steve Hamley]

Thanks everyone!

Cheers, Steve