Reacting glazes at a vertical interface

Glazes interacting at a vertical interface.

The matrix (i.e. background) glaze and inlay glaze do not overlap before firing.
The original mask for the inlay was a simple curved line.

The matrix glaze is substantially higher in Alumina and silica. It contains distinct phases, some more
mobile than others. The result of this non-uniformity of the matrix glaze is that the uniformly viscous inlay
glaze cuts through the liquid parts of the matrix, and is impeded by the rigid components
of the matrix glaze, giving the observed zig-zag pattern of the inlay.

There is diffusion of the higher alkali metals of the matrix glaze into the lower alkali metal inlay glaze;
as seen in the halo of dark brown framing the inlay, and in the yellowish shading of the thinner parts of
an otherwise ivory inlay glaze.

The dark streaks seen above the inlay result from the viscous phase of the matrix glaze pushing down on the
inlay glaze. There are streaks rather than an even line because the solid, boulder-like phase of the matrix
glaze stays put, while the fluid portion flows around the solid pieces and pushes the inlay glaze before
it in the same way a flash flood leaves boulders behind while washing away the soft sand.

Several closeups of the interaction region of the two glazes are shown and, for context, a picture of the pot.

The background glaze is longquan-iron-shino-MAlk-PSi, the inlay design is glazed with alexanderBowl_0_Z1Y.

The design is created by adhering a mask and then applying the main glaze. After drying, the mask is removed
and the open area filled in with a second glaze, using a bulb syringe with a needle applicator.