Re: direct carbon or gum bleach development
I looked at that too, and though they don't list the pigment number
for the dry pigments as they do for the watercolor paints, I'm quite
comfortable assuming that the carbon black is PBk7 and the lamp black
is PBk6. In my experience dry pigments are usually called by the
pigment name so there's no confusion; the confusion generally arises
with paint manufacturers. for example Bruce McEvoy lists four
brands of watercolor paint made from PBk7, two of which are called
"lamp black," one of which is called "charcoal grey" and one of which
is called "carbon black." Also, Winsor & Newton's paint named "lamp
black" is actually a mixture of PBk6 and PBk7.
kt
On Jan 3, 2008, at 12:31 PM, Marek Matusz wrote:
Keith,
I checked Daniel Smith web site and they both list carbon black and
lamp black, without using more detailed pigment nomenclature. My
package says carbon black on it. It lists at $10.95/lb
Marek
> Date: Thu, 3 Jan 2008 09:17:26 -0800
> From: kthayer@pacifier.com
> Subject: Re: direct carbon or gum bleach development
> To: alt-photo-process-l@usask.ca
>
> Keith, it's somewhat confusing because "carbon black" is sometimes
> used as a general term to designate black pigments made from carbon
> and sometimes to designate a specific pigment, PBk7, which is why
> pigment numbers are so important. Lamp black pigment is PBk6; PBk7
> is called sometimes carbon black and sometimes furnace black and is
> sometimes given the marketing name "lamp black," but isn't actually
> lamp black. According to some sources, PBk7 is darker and
> velvetier than PBk6.
>
> I've been sick for weeks with a flu thing that turned into
bronchitis
> and haven't got down to the workshop to continue my experiments with
> this. But because I'm still interested in exploring this, I wonder
> if you could say a little more about what's not working for you; is
> it "just" staining, or is it a problem with the bleaching too?
Thanks.
> Katharine
>
>
>
>
> On Jan 2, 2008, at 7:41 AM, Keith Gerling wrote:
>
> > Thanks Marek,
> >
> > Cold here in the midwurst and I'm staying put and making do
with what
> > I have at hand (which does not include Fabriano). But carbon
black is
> > the same as lamp black, correct? And I also have some pure
graphite,
> > and both of these stain what I've been using, which include
Masa (as
> > predicted by Loris), gessoed paper and wood, and the flip side of
> > other gum prints on various papers (which, come to think of it
does
> > include Fabriano, albeit many times immersed in water, so it isn't
> > like what you have used).
> >
> > Thanks for the offer. I'll play around a little more. The picture
> > you posted was on unshrunk paper, correct? What impresses me
the most
> > is not so much the bleaching (without seeing a before-and-after
it is
> > hard to tell what that is) but the intensity, shapness and
grain of
> > the print (resembling, come to think of it, a Ralph Gibson...)
What I
> > would very much like to do would be to produce duotones by
using this
> > process over a Van Dyke print. What are your thoughts on that?
> >
> > Thanks!
> >
> > Keith
> >
> > On Jan 2, 2008 8:09 AM, Marek Matusz <marekmatusz@hotmail.com>
wrote:
> >
> >>
> >> Keith,
> >> I have been using carbon black powder from Daniel Smith. Gum
bleach
> >> development requires higher density negative then normal gum. I
> >> would say
> >> something more like palladium negative density would be fine to
> >> start with.
> >> If you can email me a scan of your work I can perhaps
troublesoot it.
> >> Marek
> >>
> >>
> >>> Date: Tue, 1 Jan 2008 19:47:57 -0600
> >>> From: keith.gerling@gmail.com
> >>> Subject: Re: direct carbon or gum bleach development
> >>> To: alt-photo-process-l@usask.ca
> >>>
> >>
> >>
> >>
> >>>
> >>> Hi Marek,
> >>>
> >>> My attempts look atrocious. What kind of pigment are you using
> >>> for this?
> >>>
> >>> thanks!
> >>>
> >>> Keith
> >>>
> >>> On Dec 20, 2007 4:05 PM, Keith Gerling <keith.gerling@gmail.com>
> >>> wrote:
> >>>
> >>>> Awesome, Marek. This is what I want MY prints to look like.
Forget
> >>>> all that multi-coat nonsense.
> >>>>
> >>>>
> >>>> On Dec 20, 2007 2:28 PM, Marek Matusz <marekmatusz@hotmail.com>
> >>>> wrote:
> >>>>
> >>>>>
> >>>>> All,
> >>>>> More experimentation with gum printing and bleach development.
> >>>>>
> >>>>> I was intrigued by Loris's results with using unsized paper. I
> >>>>> thought
> >>>>>
> >> that
> >>
> >>>>> it would give a rather bad stain. My tricolor gum practice
> >>>>> certainly
> >>>>>
> >> led me
> >>
> >>>>> to believe this. However on numerous occasions I did
observe that
> >>>>>
> >> edges of
> >>
> >>>>> paper that I used which did not have gelatin size gave a
> >>>>> darker, more
> >>>>> uniform black. SO last week I tried to use single sized paper,
> >>>>> fresh
> >>>>>
> >> and
> >>
> >>>>> unsized Fabriano Artistico, and a throw away gum print that
has
> >>>>> been
> >>>>>
> >> soaked
> >>
> >>>>> over and over, but had a reverse side of Fabriano paper quite
> >>>>> clean.
> >>>>>
> >> My
> >>
> >>>>> overall conclusion with this set of prints is that I liked
unsized
> >>>>>
> >> paper and
> >>
> >>>>> soaked paper best. They gave crispier prints. Perhaps this
> >>>>> technique
> >>>>>
> >> likes
> >>
> >>>>> the gum to be tied up with the fiber of the paper and the
bleach
> >>>>>
> >> development
> >>
> >>>>> can give clear paper base. So I would advocate use of straight
> >>>>>
> >> watercolor
> >>
> >>>>> paper, no need to size. I have not tried any other brand,
but I
> >>>>> should
> >>>>>
> >> have
> >>
> >>>>> some at hand and will try next printing session.
> >>>>>
> >>>>> I have also experimented some more with pigment density. I had
> >>>>> a more
> >>>>> concentrated carbon stock of 3.75% carbon in 14 baume gum,
that
> >>>>> is 50%
> >>>>>
> >> more
> >>
> >>>>> then in my last set of experiments. The solutions are left
over
> >>>>> from
> >>>>>
> >> dozens
> >>
> >>>>> or maybe hundreds of experiments done in the last two years.
> >>>>> Once the
> >>>>>
> >> water
> >>
> >>>>> dried out this would result in 3.75/0.27=14% carbon/solid gum
> >>>>> mixture
> >>>>>
> >> (I
> >>
> >>>>> assume 14 baume gum is 27%). This is definitely black black.
> >>>>> Beautiful
> >>>>> velvety matte texture of the deep black to take your breath
> >>>>> away. Scan
> >>>>>
> >> of
> >>
> >>>>> the print here. This print was made on unsized Fabriano
Artistico
> >>>>>
> >> paper
> >>
> >>>>>
> >>>>>
> >>>>>
> >> http://picasaweb.googlecom/marekmatusz1/GumBleachDevelop/
> >> photo#5145909559997921266
> >>
> >>>>> The mid tones are a little bit darker on this screen that in
> >>>>> reality.
> >>>>>
> >> Maybe
> >>
> >>>>> even the two tones of black on the very edge are visible. Very
> >>>>>
> >> outside, had
> >>
> >>>>> most exposure (I uped the exposure to 6 minutes from last
time)
> >>>>> and
> >>>>>
> >> next to
> >>
> >>>>> it is somewhat lighter edge from exposure through blank
part of
> >>>>>
> >> transparency
> >>
> >>>>> (Pictorico). This is a further illustration of how a fine
tonal
> >>>>>
> >> gradation
> >>
> >>>>> can be achieved with this method.
> >>>>> I have also included an detail of the print scanned at 300
dpi:
> >>>>>
> >>>>>
> >>>>>
> >> http://picasaweb.google.com/marekmatusz1/GumBleachDevelop/
> >> photo#5145909521343215586
> >>
> >>>>> Happy printing
> >>>>> Marek
> >>>>>
> >>>>>
> >>>>> ________________________________
> >>>>> Don't get caught with egg on your face. Play Chicktionary!
> >>>>> Check it
> >>>>>
> >> out!
> >>
> >>>>
> >>>>
> >>
> >>
> >> ________________________________
> >> Get the power of Windows + Web with the new Windows Live. Get
it now!
> >>
> >
> >
>
Don't get caught with egg on your face. Play Chicktionary! Check it
out!
|