U of S | Mailing List Archive | alt-photo-process-l | Re: The Chiba System

Re: The Chiba System

Zero Chrome I missed that name :D

Thanks Kees, once you have something you are reasonably happy with I would
love to see the results.

Yes, brush coating is maybe not the best way of doing this I suppose.. I got
a smoother coating with a 3 % solution, but a lot of factors affects this.

With a 3 % solution, temperature is less important than with a 6 % sol. Have
cooled down the solution a bit before coating, which should reduce the
tendency to sink into the paper/sizing. .. Coating twice or thrice with a 2
percent cold solution is on the "to try" list ..

Might be "dip coating" :-) would be an option. No dark reaction means one
could mix up a lot of sensitised solution and store it. Then dip the plate
with mounted paper in it .. Or something like that ... I tried foam roller,
but was not happy with that pattern..

Part of this grittiness seems to be that the gelatine sinks more into the
paper, where gum tends to stay on the surface. Possibly a thicker sizing
layer might help.. Might be an idea to size twice.. My last attempts there
was sizing with 5 % sol..  Have a feeling there might be an optimum humidity
of the surface when coating, not too dry seems to give a smoother coating.
Also .. I have used brush for the sizing, that might not be the best method
either ... The sizing becomes a part of the image..

Then paper type, will later do more attempts with very thin Japanese papers,
which seems like one interesting variety/possibility with this method.
Coating on glass is also something to try ... :-)

With arches platine and aquarelle, un-sized works for the first layer, but
at second coating a gelatine layer is necessary in-between each coating, but
then these papers are meant to absorb things. Papers with a harder size
might work better.. a smooth surfaced paper gives best results..

Lots o fun :-)


On 3/24/07 5:51 AM, "Kees Brandenburg" <ctb@zeelandnet.nl> wrote:

> Hi Halvor,
> I have been testing the direct carbon-gelatin method and it looks
> promising. Finally zero-chrome printing is there!
> Some  first observations:
> - It works!
> - Working with gelatin and ferric ammonium citrate shows the true
> colors of the pigments , when coating, which is very strange when
> used to gumprinting. Feels like forgetting something.
> - Brush coating with hot pigmented gelatin is a lot more difficult
> then coating gum. Expirimenting with other coating methods is needed.
> Coating in a warm darkroom is easier the in a cold one.
> - Even when the coatingt looks smooth to the eye the final print
> still shows brush streaks
> - 'development' is fast and easy, but there is less manipulation
> possible
> - unsized papers print rather well
> - I had better results with 6% gelatin then with 3% gelatin, it also
> holds more pigment
> - It is less light sensitive then gum. For gum my exposure times are
> between 2-4 minutes for chiba-gelatine it was 10-16 minutes. I did no
> ph => 4 correction though.
> - final results look more 'gritty' then gumprints, maybe this has a
> relation with airbubbles during coating (or in the peroxide bath maybe)
> I will test some more soon.
> kees