[Clayart] interactions at interfaces

carol at knighten.org carol at knighten.org
Fri Feb 28 03:43:03 EST 2020

Re Jeff's question of what's happening at the interface:

Yes, of course those effects are ephemeral - do you see any pots anywhere that
have those colors on any large section?  Those colors individually
aren't powerful as they seem in bits and pieces in the frozen
"explosion" of the interaction.  The brightness of those colors is in the
contrast between, as in Scotch plaids.

For many micro-crystals, its as with copper red, color depends on size.  There
is a size 'window' for each color, some of the colors have larger windows,
some itsy windows.

Interaction across an interface, allows a large range of sizes to form, then
'freeze' in that size.  In this sort of dynamic 'happening' you will see a
greater range of textures and colors than otherwise.  You will see bits of the
colors that are visible only in a narrow size range.

I've got an another example where increasing alumia/silica increases the
fusibility of the glaze.  Extra alumina causes those golden metallic micro
crystals to form.  Its is high alkali glaze, with a high alkali:alumina ratio,
but no lithium.  That change is structure with increased silica or alumina
isn't a function of the lithium.

Most of my saturated iron glazes are alkali mattes, which are well known to go
glossy and homogenized with increased silica.  I'd never before known that
alkali mattes went homogenized and glossy with increased alumina.  If you look
at the land of glaze through the lense of alkali-alumia ratio, though its not
surprisiing.  What makes an alkali matte isn't how much alkali it has, rather
how much alkali and how little alumina, i.e. the alkali:alumina ratio.

    Carol Marians       
    (541) 296-4528
  carol at knighten.org 

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