Alisa and Claus Clausen on sun 6 aug 00
Recently I have been testing Chris Wolff's Plum and Cream gloss glazes. =
I am trying to work out the same effect of the two overlapped and the =
resulting opalescence, with glazes that do not contain Gerstely Borate.
In using Wolff's plum with a number of transparent and creamy and frosty =
glazes, I have found that they all give the honey yellow overlap, but =
none give the opalescense except for Tony Martens Frosty Glaze. She has =
posted the receipe previously, but maybe due to material differences in =
the USA, clayarters were not in general happy with it. I am extremely =
pleased with Frosty,=20
and use it as a staple in the workshop. It gives a fat, stable, frosty =
white. If anyone is intersted, I will ask her if I can post the recipe =
again.
Testing various iron rich glazes including Marcia Selsor's Plum just =
posted and a store bought tenmoku, I have been able to produce =
opalescences with overlapping of Frosty or Cream Gloss.
Soon when I get the needed ingredients, I will test RR version of Creamy =
Gloss without G.B. That may solve half of this beautiful combinations =
problem for me. =20
It was suggested to try overlapping Red (test recently posted) over =
Floating Blue. This produced a blue to lilac. There is a lot of color =
play when these two glazes meet. I also overlapped Tony's Frosty with =
Floating Blue, as well as my basic store bought white base. They both =
also brought up a stong blue which was attractive.
Best regards,
Alisa in Denmark.
PS. Does someone want to tell me why opalescence happens and what are =
the needed properties to achieve it?
I am working from my try and see and dedect method!
amy parker on mon 7 aug 00
Alisa - thank you for posting your glaze tests! I hope that everyone else
will do so as time permits! I did not get to the tests I planned to do this
summer - a thousand other things got in front of them, but your input is
very helpful in determining where to start when I finally do!
Amy, drowning in the annual onslaught of overripe figs & under-supplied fig
recipes! Anybody know how to make fig wine?
Amy Parker
Lithonia, GA
Andrew Buck on tue 8 aug 00
Alisa,
When I took the Ian Currie Method Workshop, if I heard him correctly, he mentioned
that the opalescent glazes usually appeared, when they appeared at all, in the
test tiles where the amount of alumina was somewhat lower than the amounts in
the more stable glazes. From what I saw, that would mean a glaze that had medium
to high amounts of silica and low amounts of alumina. Not being one of the
"glaze gurus", I always have to add that this information may be something less
than gospel. But, by my reasoning, the opalescence must come from light refracting
through the glaze which separates the light into it's component wavelengths.
These wavelengths of light being what the human eye sees as different colors.
Much like a water mist or a prism does when producing a rainbow effect. The
alumina which, among other things, acts as an opacifier, must disrupt the refractive
quality of high silica glass and stop the glimmers of color we call opalescence.
As I indicated, this is just a theory I have put together from various sources
and filtered through the black hole filing system I have for a brain. If I
am too far off base, maybe someone will correct me. I am sure there is more
to it than I have stated.
I live to learn.
Andy Buck
Raincreek Pottery
Port Orchard, Washington
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>
>Best regards,
>Alisa in Denmark.
>
>PS. Does someone want to tell me why opalescence happens and what are
>the needed properties to achieve it?
>I am working from my try and see and dedect method!
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