Lamp black - is it the Devil or not?

Hi Katherine, I was told fairly early on that lamp black is not good for
gum because of its oily origins....is this just one more gum myth? As
far as I recall it was said that it would reabsorb into the paper during
development in a random way because it floats rather than sinks. Any
comment?

I hate Ivory Black - its too brown for me. Not that I use black much
anyway.

Cheers
Kate

-----Original Message-----
From: Katharine Thayer [mailto:kthayer@pacifier.com]
Sent: Thursday, 26 May 2005 9:22 a.m.
To: alt-photo-process-l@sask.usask.ca
Subject: Re: About Van Dyke Brown

henk thijs wrote:
>
> Katherine,
> I asked about using 'Kasselse aarde' and he answered with the
> international gesture (due to the language barriere) of rubbing two
> fingers: money. His gumprints are large and of you make multiples ,
> tubes for watercolor or gouache would be too expensive.
> Apart from that the color was a very nice one.

That makes sense, for sure. And it sounds from descriptions like the
pigment is very nice to use, which is probably why it took quite a while
for manufacturers to stop using it, because people wanted it. Kind of
like alizarin crimson, people just don't want to give it up.

>
> > Van Dyke Brown (NBr8) is one of a family of organic pigments,
> > including "Earth of Kassel," which are made from surface deposits of

> > peat -- decayed wood and other plant material-- or brown coal, and
> > are unfortunately notoriously fugitive.
> >
>
> What exactly does this mean for pigments: fugitive.

According to one of my sources, "As a watercolor it (NBr8) will change
to a dull cold grey-brown after a relatively short exposure to light.
This change can be seen on many finished watercolors within a short time
of their completion."

> Will it be gone with the wind after several years even if it was
> hardened with arabic gum?

This is a very good question, which I don't think anyone knows the
answer to. Some gum printers believe (or hope, anyway) that being
encased within hardened gum arabic will somehow protect the pigment
from light-fading. I have a hard time believing that, although I would
like to. I can see how being encased in gum arabic could maybe protect
the pigment from fading due to air and pollutants in the air, (although
maybe not, because the net of crosslinked colloid is really quite
porous). But I don't see how it could protect it from light, as hardened
gum arabic itself is completely transparent.

If someone would produce fading tests that showed that fugitive pigments
don't fade when made into gum prints, I could shut up about
lightfastness forever; I'm sure everyone would be glad about that. But I
don't think I'm going to be the one to do those tests, partly because I
live where the sun doesn't shine very much, and partly because I don't
have time. But it sure would be nice if someone would come up with some
actual data on the question.

> Or is the PVA-Mowiol better suited to use the pigment?

Another good question, I don't know the answer.
>
> > However, having said that, you should not be concerned if you have
> > in your paintbox a paint named "Van Dyke Brown" unless it's been
> > around a while and isn't clearly labeled as something other than
> > NBr8, or unless, if it's new, it came from Holbein (the only
> > manufacturer still using the fugitive pigment to make watercolor
> > paint). Except for the holbein paint, all paints currently
> > manufactured under the name "Van Dyke Brown" are not made from Van
> > Dyke brown pigment. I'm looking at a set of 17 swatches of paints
> > called "Van Dyke Brown" which are made of mixtures of different
> > pigments, all of them perfectly lightfast. Since they are all made
> > from different combinations of pigments, their colors range from
> > near-black through brown to orange and red.
>
> That is what I also found,; using a watercolor from Winsor/Newton
> called Van Dyke Brown, It was really a light-brown compared to the
> pigment I tried. Can you tell me what brand makes the darkest brown.

There are some fairly dark "sepias" such as Maimeri and M. Graham, but
like many of the "sepias" and "vandykes" they are made by mixing black
with PBr7, the iron oxide from whence comes burnt umber, burnt sienna,
raw sienna etc. You might do better to just mix your own. I make dark
browns that way all the time, by mixing black with a little red and
yellow. I now use ivory black because I don't like the opacity of lamp
black, but I used to do it with lamp black and that works too. Good
luck, Katharine

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