[alt-photo] Re: Collodio-Chloride and Collodion-Based Silver-Chloride Processes: Strontium-Chloride vs Sodium Chloride?

[Francesco Fragomeni]

Yes, you guys are right.Thats why I'm pretty much setting aside thinking of
collodion as a viable substitute for gelatin in a developing out formula.

To answer you're question, this all started out of curiosity regarding
making a personal Silver-Chloride replacement for Azo. I'm interested
in longevity and being free from depending on a manufacturer for a
material. Azo has been gone for a while now and while Lodima is almost a
perfect replacement for Azo, I'm interested in something I can make and
therefore not have to worry about getting from somewhere else. Azo was a
very simple silver-chloride formula, hence why it was so easy to adapt and
produce it an extraordinary wide variety of offerings. It was the longest
and most varied run of photographic paper in history I believe. It was also
just a basic Silver-Chloride formula made with high quality materials and
under excellent control. Replicating it very closely in a hand made
emulsion has been achieved without much strain by several people including
Denise Ross, Mark Osterman, and Ron Mowrey who's formula I am using. Ron's
formula produces a paper ridiculously similar to Azo in appearance and in
its curves. I'm interested in developing-out formula simply because I
prefer to work in that method and it is what I'm used to. The workflow with
developing-out is just more my speed and I want to contact print in
silver-chloride. It basically just matches all the factors I'm looking for
in aesthetics as well as workflow.

If I can't get the gelatin formula down consistently, I'm sure
Collodio-Chloride POP won't be a problem and at that point I won't have any
quarrel with adapting my workflow.

-Francesco


On Thu, May 31, 2012 at 6:41 AM, Clarence Rhymer <crhymer at northwestel.net>wrote:

> Hello Francesco and Ryuji,
>
> I agree completely with Ryuji concerning POP vs. DOP and the pit-falls of
> old literature, but would like to note that there is *no wash *in making
> the Collodio-Chloride for POP.  Whatever one adds, stays in the mix.  I am
> not sure how one would wash it anyway.  Collodion and water just don't mix.
>  A very small amount of water is required, but not too much.  Collodion USP
> is about 25% Ethanol, 71% Ether and 4% Nitrocellulose.  If you use 95%
>  Ethanol in your Collodio-Chloride formula, you can figure out about how
> much water there will be in the final mix (some is used to dissolve the
> other ingredients).
>
> I have no idea about the using Amidol, but assuming you can make the
> product at all, why not test it with one of the more common developers.
>  Amidol is used with with Kodak Azo and Lodima to achieve a special
> look/workflow.  There is no guarantee that it will give the same result
> with another silver-gelatin emulsion even if it is similar in speed, etc.
> to Azo/Lodima, let alone a Collodion based one.
>
> Fancecso, I am unclear as to why you want a developing-out speed contact
> paper?
>
> Cheers,
> Clarence
>
>
>
>
> On 31/05/2012 7:07 AM, Francesco Fragomeni wrote:
>
>> Ryuji,
>>
>> Thanks for your thoughts. You're words are right in line with my
>> assumptions. I'm no chemist but I have a basic understanding of what
>> occurs
>> when making these types of emulsions and while various different salts may
>> have cause minor differences, I would assume that they are just that,
>> minor. From my understanding, when an emulsion of this type is sensitized
>> the NaCL and AgNO3 molecules exchange to produce silver-chloride (AgCl,
>> the
>> sensitive agent) and a non-sensitive byproduct that is typically discarded
>> in the wash (sodium-nitrate, NaNO3). The only thing I can think of is that
>> the Strontium-Chloride exchanges with Silver-Nitrate to produce
>> Strontium-Nitrate which may lend itself to some specific color, perhaps a
>> more prominent red that makes toning changes more evident. This is in line
>> will what I've read, that Strontium lent a color that made toning easier
>> to
>> see. I'm still not sure about the alcohol solubility thing.
>>
>> -Francesco
>>
>>
>> On Thu, May 31, 2012 at 2:03 AM, Ryuji Suzuki<rs at silvergrain.org>  wrote:
>>
>>  I don't have experience with collodion process but in silver gelatin
>>> process, the counter ions in the halide jet don't matter, as long as they
>>> are alkaline metal or alkali earth metal ions, impurities are well
>>> controlled, and the molar concentrations are adjusted. Those cations are
>>> just wasted without participating in any reaction that forms silver
>>> halide
>>> crystals. If solubility in alcohol is a factor, that may be one thing,
>>> but
>>> then what alcohol concentration are you talking about? In silver gelatin,
>>> sodium, potassium, and sometimes ammonium ions are used. Ammonium ions
>>> have
>>> different effects on silver halide crystals in a pH-dependent manner, but
>>> Na and K are largely irrelevant (in most cases, they are removed from the
>>> emulsion before chemical sensitization phase).
>>>
>>> Emulsions that are used for printing out processes are very different
>>> from
>>> emulsions for developed out processes. Don't underestimate that
>>> difference.
>>>
>>> I also would not put too much emphasis on stuff written in old
>>> literature,
>>> unless you can validate the statement with modern science. Systematic
>>> research of how emulsion crystals are formed and what factors have
>>> influence, etc., had to wait for sensitive instrumental amplifiers,
>>> electron microscopes, and various laboratory equipment in the 20th
>>> century.
>>> If certain issues or terminology disappeared in later literature, it
>>> might
>>> be because the earlier debate became irrelevant under the light of new
>>> science. THere are countless examples like that.
>>>
>>> --
>>> Ryuji Suzuki
>>> "When you're finished changing, you're finished." (Benjamin Franklin)
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