One of my standard production items is an oval platter made with a rolled out slab on a plaster hump mold. I have made them for a lot of years but only this last year started making them with textured slabs like this.
I have never gotten around to getting a proper slab roller. I still roll them out by hand with out any sort of gage to get the thickness consistent. I like that aspect of them.
The mold is one I made years ago while still a student. I borrowed a wooden bowl and poured plaster into it to get this negative of the shape I want to make the piece. The slab is laid on the mold and the gross clay is trimmed away with a needle tool. After patting the clay a little I trim the clay to fit the mold and pat it a bit more. The clay sets up for a day or so and I remove it from the mold and round the rim with a rib tool.
The roulette used here was made by winding a piece of cord around a cylinder of soft clay.
This roulette was impressed with the thin edge of a wooden rib.
This slab was textured with a wooden roller that has cord glued to its surface.
Here I used a narrow wooden roller with fine cord glued to it.