It's and its

Judge past the wrinkles? Meant "look past the wrinkles". Freudian slip.

Ana - you've said it.

Sorry - what have I said (recently)?

Thanks Rinouchka I will print off your clear explanation and keep it in my diary so I will have no excuse to get it wrong. I suspect I used it incorrectly the other day on GN but I can't remember which thread.

"It's ball" is not used because of possible confusion with the "it is" meaning, e.g. if you were to write "It's back" would you be referring to the back belonging to "It" or the fact that "It" had returned?"

Yes but I could then say exactly the same confusion arises with "Janet's back" but we don't drop the possessive apostrophe in that case.

I would have asked who had written the captions and expressed the hope that she/he was not teaching my child grammar.

I always had trouble remembering which was which until someone pointed out that the possessive is the same as 'his', i.e. no apostrophe - never had the problem since!