For the second set of weed cups, I first tried to scratch in the design and then fill it with white slip, using a metal rib tool to scrape it off. That didn’t work at all. My fellow ceramicists suggested that perhaps I had done it with the clay too wet (It was leather hard when I put the slip in, and leather hard still when I scraped it off). So I sanded off my messed up design and tried again, this time putting the white slip over the entire surface. While it was still leather-hard, I scratched the design into it. Since I’d already done it several times by this point, I barely needed the photo as a reference.
