Re: Clues From Echague. One.
Hi Loris, I would, from experience, strongly suggest that you do not harden
the base layer, as one might do if this were a sizing, because it needs to
allow the surface pigment layer to penetrate into it when development takes
place. It would be appreciated if you would report back on the use of
Agar-Agar as the binder for the surface pigment.
Best wishes for now.
John - Photographist - London - UK.
----- Original Message -----
From: "Loris Medici" <mail@loris.medici.name>
To: <alt-photo-process-l@usask.ca>
Sent: Sunday, May 27, 2007 7:31 PM
Subject: Re: Clues From Echague. One.
John, thanks for sharing.
When I saw mucilage, the first thing that came into my mind was
Agar-Agar, I was preparing to write a question if Agar-Agar is a good
option for this purpose but then I saw its name inside the list of
"possible" materials...
I may try Agar-Agar and Direct Carbon later since there's another carbon
printing method (a non-toxic variant by Halvor Bjoengaard) - which I also
want to try - that uses this material.
May I request another clue? Should one harden the underlying gelatine
layer? (My bet would be to not harden...)
Regards,
Loris.
Quoting John Grocott <john.grocott403@ntlworld.com>:
...
In either process the paper is coated with a layer of gelatine but
which supports, only in the Direct Carbon process, a layer of pigment
dissolved in a mucilage, instead of being incorporated in the same base
gelatine as occurs in the Carbon Transfer process.
...
So, to recap.The paper forDirect Carbon is made of a thin layer which
is generally gelatine; on this layer is coated the pigment dissolved
in a vehicle such as Gum Arabic, Tragacanth Gum, Lichen, Agar-Agar
etc., but the base coating is always formed of a thin layer of
gelatine in direct contact with the paper support.
The result of this way of preparing the paper, for one thing, is the
various qualities that can be obtained according to the proportions of
gelatine and gum muclage used and also the thickness of the pigmented
surface layer and the extent to which it penetrates into the base layer
when development takes place.