Re: sodium citrate, ammonium citrate, bleeding of borders

Ryuji,
First, I can observe that the paper has a relation to it, because Cover
bleeds way less than Platine.

Cover does not bleed in sodium citrate but it does slightly in am citrate.

I don't have any idea what is causing the differences--only two developers,
sodium and ammonium citrate. Developers were prepared same way (distilled
water), same exact time, same
exact prints and papers and exposures and all other variables same except
the two developers.

There is a possibility it may be affected by the strength of developer: I
am pretty sure the am citrate comes from B and S at 250g per 1000ml. My
recipe for sodium citrate is 1 lb for 1400ml, which I mixed myself. I have
standard recipes for am citrate to be mixed at 1/2 lb and sod 1 lb per
1400ml--don't know why the recipes are different, but this may be a factor.

What is the pH of am citr versus sod cit do you know??

All I can do is observe, but I'm hoping
that you chemists/scientists may come up with a reason for this.
Chris

> Do you know whether the differences you described are indeed due to the
> cations and not by the other factors?
>
> For example, one obvious variable to suspect is pH. The solution pH may
> be significantly different among the three versions you prepared. The
> concentration of the "reactive" species may be different due to the pH,
> due to the counterion, or both. But if these are the reasons, you should
> be able to cover the whole range of spectrum by using sodium citrate,
> citric acid, and sodium hydroxide (or sodium carbonate).
>
> Before attributing the differences you observed to the different forms
> of citrates, this point should be investigated.
>
>
> On Sun, 23 Jul 2006 21:09:20 -0600, "Christina Z. Anderson"
> <zphoto@montana.net> said:
>> Well, a kiss for Bob Kiss--
>> I tried the sodium citrate and presto, no bleeding of borders.
>>
>> However, since I ran out of Platine and my order isn't coming thru for a
>> week, I had switched to Cranes Cover/Platinotype. Therefore, I wondered
>> if
>> the reason for no bleedoff was the paper and not the developer.
>>
>> I decided to be fair to am citrate and bit the bullet, mixed 'em both up
>> and
>> today printed side by side 12 prints, half developed in sodium citrate
>> and
>> half in ammonium citrate. These are all my results for anyone who cares,
>> and I would LOVE if anyone chimed in with different results before I go
>> and
>> accept it as gospel:
>>
>> As I think Eric and Sam said sodium is warmer than ammonium--it has a
>> yellower tone to it than ammonium which is redder. Hard to see unless
>> side
>> by side and you scrutinize.
>>
>> Sodium is a titch less contrasty, too.
>>
>> Ammonium is a bit faster--printing less than 1/3 stop faster, though,
>> probably 1/6-1/4 stop by my eyeball calcs--in other words, on a 31 step
>> tablet it wasn't a full step.
>>
>> NOW (ta da) about the bleeding of borders, My am citrate is always
>> darkened
>> with metal; since it was all I used I didn't think anything of it.
>> HOWEVER,
>> when I developed all these prints today in sodium citrate, the developer
>> stayed clear. No bleeding of borders. And the Cranes Cover prints that
>> I
>> developed in ammonium citrate did bleed slightly (not like Platine) in
>> the
>> developer, so my conclusion is the bleeding is both paper and developer
>> related, and maybe another reason in there, too. But it was enough of a
>> revelation to want to stick with sodium citrate, frankly.
>>
>> That's it for today!
>> Chris
>> CZAphotography.com
>>
>>
>>
>
Received on 07/24/06-08:53:42 AM Z