What the tiles are telling you, and why your pot will never match one exactly.
Four tests on one tile
Every tile on a Clay Hole test pot is doing four jobs at once, and each part answers a different question. Learn to read the four and a tile stops being a color swatch and starts being a report.
Broad vertical coverage is the sanded smooth section with no texture at all. That is the glaze on its own terms, and the honest answer to what color it fires and whether it runs down a plain wall.
Deep chunky texture is the harsh rolled line. It shows you what the glaze does when it has somewhere real to gather. A glaze that breaks will go pale on the ridges and pool dark in the trough.
Shallow texture is the spiral stamp, the gentler question. Some glazes only respond to deep carving and ignore a light stamp completely, and this is where you find that out before you commit a whole pot to a subtle surface.
Wipe away texture is the number itself, where we fill the recess with glaze and wipe the surface around it clean. That tells you how the glaze behaves in an inlay, which is the technique most likely to disappoint you if you have not tested it.
Thickness is on the tile too
Most tiles are not a single even coat. Where the glaze pooled you are looking at what three or four coats do, and where it thinned over a raised edge you are looking at one.
A single tile is often showing you the entire range of that glaze at once, which is why two members can use the same jar and get results that look unrelated. Neither of them did anything wrong.
That is the most useful habit to build here: stop asking what color a glaze is, and start asking what it does at the thickness you tend to apply.
Why your pot will not match the tile
The tile is flat, small, and fired on our clay. Your pot is curved, uneven in thickness, and sits somewhere else in the kiln. Every one of those changes the result.
Clay body matters more than most people expect, especially with anything translucent, because the color underneath becomes part of the finished color. Form matters just as much: a glaze that pools beautifully in a carved line has nowhere to gather on a smooth cylinder.
Kiln position is real too. The same shelf can vary, and a glaze already near its limit will show that variation first.
The part nobody likes saying out loud
Glaze is chemistry running at over two thousand degrees, and chemistry does not take instructions. Sometimes you get exactly what the tile promised. Sometimes you open the kiln and find something you did not ask for and could not repeat if you tried.
That is not a fault in the glaze and it is not a fault in you. It is the material. Reactive glazes in particular are sold on being unpredictable, and the same property that makes them spectacular is the one that occasionally ruins a piece you cared about.
The potters who seem to have the best luck are the ones who test. Not because testing removes the surprise, but because it tells you which glazes are worth gambling a good pot on and which belong on the outside of a mug.
What to do with all of that
Use the four sections of the tile to decide whether a glaze breaks, moves, stays put, or works in an inlay. Use the family page for coats and firing notes. Use your own test tile, on your own clay, for anything you actually care about.
And when a pot comes out looking like nothing you planned, photograph it before you decide whether you like it. Half the glazes people love here started as an accident somebody kept.
