Medieval ways to paint baked clay

My medieval history class will be making drop spindles, making the whorls out of clay. Since glazing spindles wasn't really a thing anywhere during the Viking Age, I was thinking of painting them afterward. But, what type of paint to use?

Did anybody paint clay objects after they were fired? Are there museum examples to look at?

What types of binders were used back then? Egg tempera, milk paint, gum arabic, linseed? Which ones did the Vikings use? (Since we'll be studying the Vikings during the time we're making the spindles)

All but the gum arabic of those would only be good for a day (or two in the case of linseed), so how much pigment will I waste if we make paint on the spot and it doesn't all get used up?

Which leads me to wonder, how does gum arabic do on clay? Did anyone ever try it in the medieval times?

If anyone finds/knows anything, I'd love to learn about it! If I find out anything, I'll try to post it here in this thread to help others.

My students will be studying the Viking Age while making their spindles. And, yes, the Vikings usually used stone for whorls...I don't have access to that much soapstone or other carvable stone, and it's probably pretty tricky to get the symetrical. So, we'll be using clay to make whorls instead. Lots of people in medieval Europe used clay, so I'll just explain to the kids about soapstone and why we're making them out of clay.

Still, I want to show the kids as many Viking spindle whorls as possible to take inspiration from. They're weirdly hard to find, though! But, I did find Helg Reproduction makes stone spindle replicas and apparently shows which find they were based off of in his facebook page. For now, here's a link to his page to do more research: https://helgreproductions.com/2025/02/05/soapstone-spindle-whorls/. One is even painted. He went with tempera paint, but I didn't see anything in the primary source about the type of paint binder.

I wonder if carved statues would be an equivalent. These used to be vibrant colours painted on.  

I admit, my brain leaps to egg tempura (i think that's the word, at least my spellchecker says it is) paint.  But my brain filling system has lost the citation why I feel egg paint is common for clay as glaze replacement in the medieval period.