Bar stools

Could you try spraying/painting them?
I have used a matt black spray successfully on other things - from Halfords.
I use a few coats.
You may need to respray to keep them looking lovely - obviously you'd also need to mask the seat well.

I spray outside on newspaper on a still day. Several thin coats are nicer than one thick one and won't "run".

Yes I would try spraying them in Matt black. Might have to lightly sand & prime.
Some sprays already have the primer.
What colour are your seats? Are they cantilever, legs, or either gas lift?

It would be worth spraying a lacquer finish over the top to protect them too

NotSpaghetti

Could you try spraying/painting them?
I have used a matt black spray successfully on other things - from Halfords.
I use a few coats.
You may need to respray to keep them looking lovely - obviously you'd also need to mask the seat well.

I spray outside on newspaper on a still day. Several thin coats are nicer than one thick one and won't "run".

Could maybe unscrew the seats

Oh yes,
I hadn't envisaged gas-lift ones.
That might be tricky.

And yes, the seats may be bolt-on. Good idea to just remove them.
If you do this I'd number them so they match back up and screws definitely go back in easily.