Didn't the painter acknowledge his responsibility and arrange to rectify
the problem?

Seems to me that if the floor was in reasonable condition before he did
hid work, and he didn't warn you that something like that might happen
then I it's his his responsibility to make things right.

I suppose except for the fact that he was using a product as designed and
was not negligent in any way from what I can see. If I was on a jury and
this was a lawsuit I would vote not guilty. There were many other places
on the floor where there was no damage from the tape. It was a fresh roll
of tape.... I saw him open it up. So either it was some magical way that
the sun was hitting the tape (indeed it was hitting the tape thru the
window at those spots but it was hitting other spots too with no damage
caused) or there was something wrong with the tape.... or there was
something wrong with the 10 year old floor.

I'd politely contact the tape manufacturer and the flooring company and ask
them about the situation. (Whats' the warranty on your floor, BTW?)

If either company ignores you, then send a registered letter.

Technically, *IF* the tape was defective, the painter is responsible for the
damage. It might not have happened if had used brand Y instead of brand X
tape. You didn't tell him what tape to use. etc... He would be the one going
after the tape company for restitution. Of course, the floor could have been
defective, meaning the homeowner goes after the flooring company.

Personally I doubt the tape could have caused soooo much damage that it
isn't satisfactorily repairable, but I'm not there to judge.