EDTA Tetrasodium

[hka]

Can some body tell me of there is a substitute for EDTA Tetrasodium? I like to try the Rollo Pyro recipe but can't find the stuff.
Thanks

 

[Ole]

Use distilled water for mixing, and you won't need it at all.

 

[hka]

Thanks Ole,
That's a very quick and clear answer.

 

[Mike Wilde]

EDTA salt's roll - is calgon a substitute?

I am aware that EDTA , or its salts is a chelating agent, (not sure on the speling of that word); i.e it holds metals etc in solution -

In the north american market would a small amount of calgon not do the same?

I mix RA-4, C-41 and E-6 colour developers from scratch, and usually have a few gallons of previously boiled reverse osmosis filtered municipal water sitting under the darkroom sink un glass gallon jugs to use for mixing the developer in. There have been times where the jugs have unwittingly become depleted, and I want to get a batch of RA-4 prints out. I have on few times used a gram per litre of calgon, as the first ingredient added, and have not detected any change in the outcome of the prints. This testing has been purely subjective, and not analytical.

Does anyone else have cmoments to offer on this practice?

 

[hka]

I saw in an other recipe for Rollo Pyro EDTA-Na4.
Is this component the same as EDTA Tetrasodium?
And the also use distilled water for mixing...!

 

[Robert Hall]

IIRC, yes, it's the same. It is supposed to pick up reduced silver so that it wont stain the negative. I know it's a chelating compound that will take iron and other minerals out of the water to make it "softer". I use softened and filtered water on my negatives and add the edta as well, simply becuase I have a bunch of it. Calgon is pretty much the same thing, but Calgon also has a few other things, like fragrance, and I have no idea how that may effect the development.

I also understand that EDTA Na2 is soluble in water but has a lower ph than Na4. Again, I wouldnt know how muchof an effect this would have on activity.

I have never seen streaking in 8x10 negatives or smaller, but I tend to be a little superstitious with my larger negatives.

Best of luck,

 

[Gerald Koch]

Both EDTA and Calgon are chelating agents. However, EDTA is used for other purposes in developers and its presence in Rollo Pyro may be for other reasons than water softening.

EDTA, Na4 is available from Dead Link Removed for $14.35 per lb plus shipping.