On Mon, 13 May 2019 19:08:22 +0100, Chris Green wrote:

We've had a room skimmed but want to paint it as soon as possible for
M-I-L to return from a minor operation.

Just skimmed? How thick? Room ventilated/heated?

Trying to establish how long the plaster may take to dry.

It would appear that there are special paints which can be used in
this situation, e.g. Dulux Supermatt. Are these really necessary? ...

If you have the time to leave a few mm of skim to dry in
heated/ventilated room, say 24 to 48 hours (plastered today paint on
wednseday) probably not. I'd use a slightly diluted first coat so the
"dry" plaster doesn't suck the moisture out of the paint too quickly,
leaving it as film rather than adhered.

... and how soon can one actually paint using them?

Read the instructions?

--
Cheers
Dave.