Queunda@AOL.COM on sat 11 nov 00
Hello.
I was wondering how ancient Chinese, Koreans, etc., got there celadon colors.
Did they use black or red iron oxides? Red clay?
any one know any history of glaze ingredients?
Why I am at it, does any one know where cobalt comes from?
Neville Longbottom
enjoying the crisp, cool weather hear at Hogwarts England.
Marcia Selsor on sat 11 nov 00
Neville,
I heard once many many years ago that the little black pebbles in rivers
and streams were the source of a cobalt/manganses colorant for
blue/black slip painting under the celedons.
The rocks were fired making them easier to crush and refine. I have
never explored this.
As for a source of info, probably the most current would be Tichane's
Celedon Blues.
Marcia
Queunda@AOL.COM wrote:
>
> Hello.
> I was wondering how ancient Chinese, Koreans, etc., got there celadon colors.
> Did they use black or red iron oxides? Red clay?
> any one know any history of glaze ingredients?
> Why I am at it, does any one know where cobalt comes from?
>
> Neville Longbottom
> enjoying the crisp, cool weather hear at Hogwarts England.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/spain99.html
http://www.silverhawk.com/ex99/selsor/welcome.html
mary simmons on sat 11 nov 00
Hey Neville-
You can make some real simple celadons with custer feldspar, whiting and
ANY clay that has some iron in it, Less iron (more iron tends toward green. You should try this recipe using various
clays--it is quite informative and makes you start thinking about local
materials and the historical use of them in ceramics-
80 custer feldspar
16 whiting
4 clay
try EPK, grolleg, add .5% red iron oxide
ball clays, barnard, etc have more iron, so when you use these clays, don't
add any additional iron. Red iron oxide is less "potent" than black, but
the same colors will occur--less iron=more bluish colors, more iron=more
greenish.
The large amount of custer will make these celadons craze like
crazy.......you can play around with the amounts of custer and clay to
reduce the crazing if you don't like it.
cheers-
Mary
Snail Scott on sat 11 nov 00
Some people speculate that the first celadons were simply
contaminated by trace iron in the raw materials, and people
liked the effect!
-Snail
At 01:16 AM 11/11/00 EST, you wrote:
>Hello.
>I was wondering how ancient Chinese, Koreans, etc., got there celadon colors.
>Did they use black or red iron oxides? Red clay?
>any one know any history of glaze ingredients?
>Why I am at it, does any one know where cobalt comes from?
>
>Neville Longbottom
>enjoying the crisp, cool weather hear at Hogwarts England.
>
>___________________________________________________________________________
___
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Hank Murrow on sat 11 nov 00
>Neville Longbottom wrote;
>I was wondering how ancient Chinese, Koreans, etc., got there celadon colors.
>Did they use black or red iron oxides? Red clay?
>any one know any history of glaze ingredients?
>Why I am at it, does any one know where cobalt comes from?
Dear Neville; Please check out Nigel Wood's book, "Chinese Glazes"
published by U of Penn press. Nigel covers this subject in the most
complete and generous way.
Cheers, Hank in Eugene
Keiko Suga & Noel Oard Mapstead on sat 11 nov 00
a new book and an excellent source of history and recreating chinese celadons, as i
have posted before, is:
Chinese Glazes: Their Origin, Chemistry, and Recreation, by Nigel Woods,
first published in Great Britain 1999, A&C Black (Publishers) Limited
33 Bedford Row, London WC1R 4JH; and ISN 0 8122 3476 6
korean celadons for the koryo dynasty (ad918-1392) used porcelain stone (instead of
clay) added to wood ash, with low red iron and low titania over grey firing
stonewares
wood ash is also known as "glaze ash". the chinese created glaze ash by burning
mountain brushwood in alternating layers of limestone and mixed with persimmon
wood, burned to ash and mixed with porcelain stone (micaceous rock) a mix of
quartz, hydromica and primary clays low in soda feldspar
calcining limestone (calcium carbonate, CaCO3) gives quicklime (CaO), but then
rehydrates in open air to give calicum hydroxide (Ca(OH)2; which is then weathered
and refired many times and then pissed on, giving 92% calcium carbonate & 8%wood
ash.
then there was raw glazing with a low bisque sintering, and more layer glazing,
very thick
noel oard mapstead
Queunda@AOL.COM wrote:
> Hello.
> I was wondering how ancient Chinese, Koreans, etc., got there celadon colors.
> Did they use black or red iron oxides? Red clay?
> any one know any history of glaze ingredients?
> Why I am at it, does any one know where cobalt comes from?
>
> Neville Longbottom
> enjoying the crisp, cool weather hear at Hogwarts England.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
vince pitelka on sat 11 nov 00
It is my understanding that the first celadon-like glazes were just feldspar
and wood ash, with the green color resulting from the iron in the wood ash.
With the Chinese love of jade, green colors were cultivated. At some point
they stopped using ash, and found other sources of iron. Another post
mentioned high-iron pebbles being calcined and crushed to provide an iron
source, and that sounds familiar. I just have too much stuff floating
around in my skull.
Best wishes -
- Vince
Vince Pitelka
Home - vpitelka@dekalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
http://www.craftcenter.tntech.edu/
WHew536674@CS.COM on sat 11 nov 00
One of your countrymen wrote a great book that should give you the answers to
all your questions. It's Chinese Ceramics by Nigel Wood. Great book.
Joyce A
rickmahaffey on sun 12 nov 00
Vince
While in China in '99 I saw a display of Proto-Celadon pots. I believe
they were in the Forbidden City Ceramics Collection. I recall the dates
were about 400 B. C. The appearance was that of a very thin ash glaze.
The pots had a slightly Greenish cast to the Gray color. There was no
information on composition, but I was surprised by the dates.
Rick Mahaffey
Tacoma Community College
Tacoma, Washington, 98466, USA
Mike Gordon on sun 12 nov 00
Hi Mary,
Could you tell me what cone or temp this glaze fires to and oxy or
reduction? Thanks Mike Gordon
Craig Martell on sun 12 nov 00
Vince sez:
>It is my understanding that the first celadon-like glazes were just feldspar
>and wood ash, with the green color resulting from the iron in the wood ash.
Hi:
The recent tests I've been doing with Tennessee woodash would certainly
confirm the above. Line blends with the woodash and soda feldspar gave
several crackle celadons. As the woodash deceased, the effect moved into
the chun blue zone. The woodash has an iron content of about 4.5%.
regards, Craig Martell in Oregon
Dave Finkelnburg on sun 12 nov 00
Hi All!
Following the comments of Vince and Craig about celadon's being
originally made from wood ash and feldspar, it seems logical to me that the
feldspar may have come from volcanic ash. Korea is famed for its Koryo
celadons, made in a time when the potters there had few mechanical devices
to grind raw materials. According to Tichane, in "Ash Glazes," pine wood
ash is about half calcium, about 80% fluxes overall. The dominant tree on
Korean hills today is pine, and likely was during the Koryo period. Korea's
geology shows a history of volcanic activity which would have produced
volcanic ash. Both volcanic ash and wood ash can be used as found to make
glazes. The volcanic ash would have supplied alumina, silica and iron, as
well as some fluxes, and the wood ash the remainder of fluxes. A clay could
also have been added to aid application. This sort of recipe seems to me to
be exactly what a potter dependent on local materials and lacking machines
would have used.
Dave Finkelnburg
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Paul Taylor on mon 13 nov 00
Dear Dave and all
The chinese and I expect koreans as well have for thousands of years the
most efficient way of grinding materials, water power for a hammer mill and
settling pits and labor for getting an exact particle size for their
materials. This was very labor intensive but gave a much better prepared raw
material than a ball mill.
The book CHEN TE CHEN by robert tichhane gives a comprehensive overview
of the technology used.
I think the original post was asking about the materials used in the
southern and northern sung and later.
I thing the materials used were potash bearing rocks and clays with no
titanium and little soda mixed with calcium carbonate again with no
titanium. the secret was in the mixing and firing. These rocks are not
available through our material suppliers I wish they were. BUT substitutes
can be found.
I expect the iron used was in the raw materials. but their methods of
settling the materials would have allowed the particle size of the iron
oxide to be of the finest.
Any clear glaze made out of any fluxed glass with one percent iron in a
reduction atmosphere will make a crazed olive green. Some call that celadon.
Regards from Paul Taylor
http://www.anu.ie/westportpottery
> From: Dave Finkelnburg
> Reply-To: Ceramic Arts Discussion List
> Date: Sun, 12 Nov 2000 10:54:37 MST
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Source of Celadons
>
> Hi All!
> Following the comments of Vince and Craig about celadon's being
> originally made from wood ash and feldspar, it seems logical to me that the
> feldspar may have come from volcanic ash. Korea is famed for its Koryo
> celadons, made in a time when the potters there had few mechanical devices
> to grind raw materials. According to Tichane, in "Ash Glazes," pine wood
> ash is about half calcium, about 80% fluxes overall. The dominant tree on
> Korean hills today is pine, and likely was during the Koryo period. Korea's
> geology shows a history of volcanic activity which would have produced
> volcanic ash. Both volcanic ash and wood ash can be used as found to make
> glazes. The volcanic ash would have supplied alumina, silica and iron, as
> well as some fluxes, and the wood ash the remainder of fluxes. A clay could
> also have been added to aid application. This sort of recipe seems to me to
> be exactly what a potter dependent on local materials and lacking machines
> would have used.
> Dave Finkelnburg
>
> _________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
>
> Share information about yourself, create your own public profile at
> http://profiles.msn.com.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
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