View Full Version : EDTA Solution Stability?

Steve Hamley
17-Nov-2011, 11:04

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

17-Nov-2011, 11:17
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.


Steve Hamley
17-Nov-2011, 11:21

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

17-Nov-2011, 12:05
I make up the EDTA and store it separate with no problems.

Drew Wiley
17-Nov-2011, 12:58
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
17-Nov-2011, 13:43
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
17-Nov-2011, 15:37
Thanks everyone!

Cheers, Steve