Question for chemistry wizards

George Papantoniou · Apr 18, 2007

One of which I am not...

I found a bottle of EDTA (Ethylenedinitrilotetraacetic acid) in the shop and I wanted to know if I should buy it or not. I think it's 1 kg and it costs 35 euros (45 US$). On the bottle you can read: "Ethylenedinitrilotetraacetic acid, disodium salt dihydrate". Is it good for photographic use ? Is this a good price ?

Ian Grant · Apr 18, 2007

In 30 years the only time I've used EDTA is in colour chemistry, a poster in the articles section seems to use it extensively in his B&W reversal processing.

Price wise it is cheap to buy, that seems expensive.

Ian

colrehogan · Apr 18, 2007

I always thought that EDTA stood for Ethylenediaminetetraacetic acid.

Monophoto · Apr 18, 2007

George -

Do you actually have a use for it? If not, then whether the price is reasonable is irrelevant.

A 500g container costs US$17 at B&S, so my reaction would be to think that the price is a bit high.

Photo Engineer · Apr 18, 2007

George;

That is a good price but probably more than you need. At first glance, I thought it read NTA. For anyone that read the initial post, sorry. I reedited.

PE

Loris Medici · Apr 18, 2007

Na2 EDTA (disodium EDTA, there's also a different compound: Na4 EDTA -> tetrasodium EDTA... These are aliases, not proper chemical names BTW.) is a chelation agent which is very useful if you're doing iron based alternative processes such as Pt/Pd, Kallitype, Vandyke, Agryrotype, New Chrysotype. It's commonly used as the primary "acidic" clearing bath (at 2-5% strenght). Na4 EDTA is/may be used later as secondary alkaline clearing bath (often mixing it with 2-5% Sodium Sulfite). You need an acidic first clearing bath with iron processes. If not, residual unexposed iron may react with the -OH functional group of the alkali solution and form insoluble Ferric Hydroxide which will stain the paper yellow and won't wash out since it is insoluble.

I can buy a kg of this compound for just $5 here in Istanbul.

Hope this helps,
Loris.

George Papantoniou · Apr 19, 2007

colrehogan said:
I always thought that EDTA stood for Ethylenediaminetetraacetic acid.

Diaminoethanetetraacetic acid
Edetic acid
Edetate
Ethylenedinitrilotetraacetic acid
Versene
Ethylene diamine tetracetic acid

These are the names Wikipedia mentions that are used for it...

Ray Heath · Apr 19, 2007

George Papantoniou said:
One of which I am not...

I found a bottle of EDTA (Ethylenedinitrilotetraacetic acid) in the shop and I wanted to know if I should buy it or not. I think it's 1 kg and it costs 35 euros (45 US$). On the bottle you can read: "Ethylenedinitrilotetraacetic acid, disodium salt dihydrate". Is it good for photographic use ? Is this a good price ?

g'day george

what would you use it for?

distilled water may be of more use in the darkroom, and it's really cheap

George Papantoniou · Apr 19, 2007

I was intendig to use it as a clearing bath for pt/pd prints... I need 50g for each lt of clearing bath, so with a kg of it I can make 20 lt of clearing bath.

Loris, I think that when I come to Istanbul (not Constantinople, tum, di-tum, di-tum) I'll buy some EDTA... for the time being, I have no choice... Could there be two kinds of it (this one I found seems quite "pure", since it's sold for chemistry labs, in a nice bottle etc)...

Loris Medici · Apr 19, 2007

Kalimera Yorgos,

See:
Bereket Kimya, http://www.bereketkimya.com/iletisim.html
(The picture on top, it's very close to Galata Bridge)
For buying chemical compounds in Istanbul. Right next to Bereket Kimya there's another store for chemicals: Balmumcu Kimya.

Yassou,
Loris.

P.S. Do not mix it all in once, mix fresh before each session.

George Papantoniou said:
I was intendig to use it as a clearing bath for pt/pd prints... I need 50g for each lt of clearing bath, so with a kg of it I can make 20 lt of clearing bath.

Loris, I think that when I come to Istanbul (not Constantinople, tum, di-tum, di-tum) I'll buy some EDTA... for the time being, I have no choice... Could there be two kinds of it (this one I found seems quite "pure", since it's sold for chemistry labs, in a nice bottle etc)...

davido · Apr 19, 2007

a chelation agent which is very useful if you're doing iron based alternative processes such as Pt/Pd, Kallitype, Vandyke, Agryrotype, New Chrysotype. It's commonly used as the primary "acidic" clearing bath (at 2-5% strenght). Na4 EDTA is/may be used later as secondary alkaline clearing bath (often mixing it with 2-5% Sodium Sulfite). You need an acidic first clearing bath with iron processes.

Loris, do you use EDTA in place of Citric Acid for initial clearing baths with VDB and Kallitypes? Is there a noticable difference on how they both clear or in the resulting prints?

thanks
david

Loris Medici · Apr 19, 2007

I personally use EDTA only with New Chrysotypes and/or Ziatypes. Never used it with Kallitype and/or Vandyke (only citric acid and plain sodium sulfite) - not because I think it's bad; I just haven't bothered... I believe it's a good practice to use Na4EDTA + Sodium Sulfite as the last clearing bath / before final wash - especially for prints you're going to sell or give someone as gift.

Regards,
Loris.

davido said:
Loris, do you use EDTA in place of Citric Acid for initial clearing baths with VDB and Kallitypes? Is there a noticable difference on how they both clear or in the resulting prints?

thanks
david

George Papantoniou · Apr 20, 2007

Loris Medici said:
Kalimera Yorgos,

See:
Bereket Kimya, http://www.bereketkimya.com/iletisim.html
(The picture on top, it's very close to Galata Bridge)
For buying chemical compounds in Istanbul. Right next to Bereket Kimya there's another store for chemicals: Balmumcu Kimya.

Yassou,
Loris.

P.S. Do not mix it all in once, mix fresh before each session.

Now, that's one (more) good reason for me to travel to Istanbul...

Loris Medici · Apr 20, 2007

George Papantoniou said:
Now, that's one (more) good reason for me to travel to Istanbul...

Another landmark for you - in order to let you find the place more easily: the big L shape building (labeled: Misir Carsisi) on lower left corner is the "Spice Bazaar".

Regards,
Loris.

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