Ron Collins on fri 9 feb 01
We took a houseguest to the cloud/rain forest near Coban this weekend =
and I dug some yellow ocher and a more orange ocher--I have never used =
this pigment, and while I am going to do some tests today with my =
current glazes, I was wondering if anyone could tell me some results to =
expect, firing at 04, and do you have any interesting uses for this =
pigment? Melinda in Guatemala
Kim Peterson on fri 9 feb 01
Melinda,
I have often used ochers for a colorant in pit firing.. Bruh is on bisqued
and pit fire. It seems to sork best when the heat is uneven. Colors vary
from dull yellow to dark black.
Kim
>From: Ron Collins
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: yellow ocher
>Date: Fri, 9 Feb 2001 07:42:24 -0600
>
>We took a houseguest to the cloud/rain forest near Coban this weekend and I
>dug some yellow ocher and a more orange ocher--I have never used this
>pigment, and while I am going to do some tests today with my current
>glazes, I was wondering if anyone could tell me some results to expect,
>firing at 04, and do you have any interesting uses for this pigment?
>Melinda in Guatemala
>
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Khaimraj Seepersad on fri 9 feb 01
Hello to All ,
Melinda ,
it depends on how much Iron Oxide is in the material .
I use local ochres in oil painting , after passing the
material through a -325 mesh , and using lots of
water to wash out solubles.
When I crush the dried , clean cake under a muller
and add oil , the opacity or translucency tells me
if there is any real % of Iron Oxide in the material .
If it is after the oil addition , opaque , there is enough
iron oxide to justify use as a paint .
Translucent - then the next test is as a slip for use
in burnishing .
Translucent -
For glazes , depending on the amount used and at
04 , it may have to be a Borosilicate Glaze , you
will get red brown , to dark brown , to green brown
or just watery browns. Test .
Reduction you get green types mostly - olive types
or if very lucky with small quantities , blues and
celadons. Test .
With Alkalines , I got , using ochres in small quantities
soft watery earth pinks , too feminine for me to use .
I have used ochre clays to float borate frits , and got
reddish brown glazes - needed some silica to work
properly .
Just being silly -
You can also use egg yolk or gum arabic and pigment
to paint on CaC03 coated pots [ Mayan style ] .
Or if you really want to be native , beat some local ficus
bark thinly [ paper thin ] , coat with a gum / CaC03 coat
and do your own Popul Vuh or Dresden Codex .
Marzo , Marzo .
All I can suggest is try . You may not wish to clean
the ochres , as I do .
Stay well ,
Khaimraj
-----Original Message-----
From: Ron Collins
To: CLAYART@LSV.CERAMICS.ORG
Date: 09 February 2001 9:08
Subject: yellow ocher
We took a houseguest to the cloud/rain forest near Coban this weekend and I
dug some yellow ocher and a more orange ocher--I have never used this
pigment, and while I am going to do some tests today with my current glazes,
I was wondering if anyone could tell me some results to expect, firing at
04, and do you have any interesting uses for this pigment? Melinda in
Guatemala
George Mackie on fri 9 feb 01
Melinda
Ocher in cone 04 oxidation comes out much like the color it is in the raw
only paler and it can give a nice warm tone to otherwise starkly white,
paint-like glazes which you want to make less harsh, 2% or less will do it.
There may be contaminants in the stuff you mined which would make it
interesting. One lot of ocher I have has tiny little black spots like
ilmenite plus green spots of various sizes like copper oxide but nothing
that won't go through a 40 mesh grid. The challenge with low fired glazes is
to make them interesting by varying texture and spottiness and hue, too
often they are bland and boring, so its a good idea to try out natural ores.
George
At 07:42 AM 2/9/01 -0600, you wrote:
>We took a houseguest to the cloud/rain forest near Coban this weekend and I
dug some yellow ocher and a more orange ocher--I have never used this
pigment, and while I am going to do some tests today with my current glazes,
I was wondering if anyone could tell me some results to expect, firing at
04, and do you have any interesting uses for this pigment? Melinda in Guatemala
>
>
Ron Collins on sun 11 feb 01
Dear Alisa,
This ocher is so fine that no crushing is necessary...in fact, it
polishes, but not as much as terra sig...everything here is volcanic/related
and the mix varies, I'm sure, from region to region...but natural materials,
which I never bothered with before, have given me results beyond what I
would have thought possible at 04 ox. Now if I just had time to make some
of my own work, and not just give classes and play with the glazes, I might
actually get somewhere....
Lili Krakowski on mon 12 feb 01
In my albeit limited experience yellow ochre produces effects like iron in
a weakened form. HOWEVER "yellow ochre" like "iron"
and "rutile" and I am sure others, vary hugely. Not when you buy'em from
a supplier, although those vary too, but when you dig'em up. I would
suggest you clean the material to eliminate stones etc then replace
iron with it in a knownglaze, so you cn compare. Good luck.
Lili Krakowski
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