[pure-silver] Re: Selenium toning + Agfa Sistan

We may never get the complete story (Agfa doesn't have a research staff
anymore either), but they are talking about Sistan working on silver salts
produced through oxidation in the print's future. Remember, Sistan is
applied to the print and should not be washed out afterwards. It is staying
in the print to work on future silver oxidations, turning them into
insoluble silver compounds. The text says that these compounds build the
protective layer at that time.

Selenium and KBT will protect the silver from this oxidation by forming mor=
e
stable silver selenide and silver sulfide, respectively. Hence, Sistan has
nothing to do work on in a fully toned print. However, these toner
conversions are never 100%, and that's why I like the Sistan treatment in
addition to toning.

IMHO, Sistan is not a replacement for toning as this brochure promotes. The=
n
again, using Sistan without prior toning is better than using no print
protection at all. However, there are arguments that Sistan might not be
needed if the print has been toned. I just like to be sure, and Sistan
cannot hurt as a final treatment, if its residue is wiped off.




Regards



Ralph W. Lambrecht




On 11/25/04 11:56 PM, "Claudio Bonavolta" <claudio@xxxxxxxxxxxx> wrote:

> Thanks Ralph,
>=20
> This is how I thought Sistan works but I've had a doubt while reading the=
ir
> documentation (sorry, I
> found it in german only):
> http://www.agfaphoto.com/de/photo/pdf/products/Sistan_Broschuere_2003_D.p=
df
> and particularly on page 4:
> --------------------------------------------------------------------
> "Ausfallende" Wirkung mit Schutzmantel.
> Durch die Behandlung mit Agfa SISTAN wird das sich durch
> Oxidation bildende Silbersalz als farblose, unl=F6sliche
> Silberverbindung ausgef=E4llt.
> Diese neu entstandene, vorteilhafte Sibersalzverbindung ist
> lichtunempfindlich, sehr stabil und umh=FCllt das Silberkorn wie
> ein Schutzmantel.
> F=FCr hohe Archivfestigkeit und eine Stabilit=E4t, die fast
> den Konservierungsgrad einer Schwefeltonung erreicht.
> --------------------------------------------------------------------
> It seems like, but maybe it's just my german which is very limited, Sista=
n
> creates a layer of silver
> salts protecting the metallic silver.
> And thus my question, will it create this layer if the metallic silver is
> already covered with
> selenium ?
>=20
> I hope you're right, Sistan looks like a very convenient solution to prot=
ect
> prints without
> modifying their aspect (or prints toned with toners not very archival).
>=20
> Best regards,
> Claudio Bonavolta
> http://www.bonavolta.ch
> ----- Original Message -----
> From: "DarkroomMagic" <info@xxxxxxxxxxxxxxxx>
> To: "PureSilverNew" <pure-silver@xxxxxxxxxxxxx>
> Sent: Thursday, November 25, 2004 1:11 AM
> Subject: [pure-silver] Re: Selenium toning + Agfa Sistan
>=20
>=20
>> Claudio
>>=20
>> Think of selenium and sulfide as creating 'protective layers' of modifie=
d
>> silver. Think of Sistan as a 'pollution sponge' added to the paper to be
>> there 'just in case'. The function of Sistan is very different from that=
 of
>> toners but not unlike the function of calcium carbonate to 'buffer' moun=
t
>> boards to protect them from potential pollution attacks in the future. U=
se
>> it in addition to toning prints, not as a replacement.
>>=20
>>=20
>>=20
>>=20
>>=20
>> Regards
>>=20
>>=20
>>=20
>> Ralph W. Lambrecht
>>=20
>>=20
>>=20
>>=20
>> On 11/25/04 12:30 AM, "Claudio Bonavolta" <claudio@xxxxxxxxxxxx> wrote:
>>=20
>>> Dear All,
>>>=20
>>> I like light (1+19) selenium toning because of the increased Dmax it gi=
ves
>>> to
>>> the prints without a
>>> important change of color (well, with Ilford MG FB).
>>> As it seems selenium toning with this concentration is no more the pana=
cea
>>> to
>>> keep our prints alive,
>>> will an additional bath of Agfa Sistan help in any way ?
>>> Or, in other words, can Sistan still make the protective layer once the=
re is
>>> a
>>> layer of selenium ?
>>>=20
>>> Thanks,
>>> Claudio Bonavolta
>>> http://www.bonavolta.ch
>>>=20
>>>=20
>>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
>>> =3D=3D
>>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>>> To unsubscribe from this list, go to www.freelists.org and logon to you=
r
>>> account (the same e-mail address and password you set-up when you
>>> subscribed,)
>>> and unsubscribe from there.
>>=20
>>=20
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> =3D=3D=3D=3D=3D=3D=3D=3D=3D
>> To unsubscribe from this list, go to www.freelists.org and logon to your
>> account (the same e-mail
> address and password you set-up when you subscribed,) and unsubscribe fro=
m
> there.
>=20
>=20
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> To unsubscribe from this list, go to www.freelists.org and logon to your
> account (the same e-mail address and password you set-up when you subscri=
bed,)
> and unsubscribe from there.

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