On 14/05/2021 09:49, Brian Gaff (Sofa) wrote:
Well water expands when it freezes, and I'd imagine that might promote
separation, but I don't know enough about the chemistry to know if a good
stir will make it OK again.
Brian

Usually not if it has been hard frozen.

It physically separates the pigments into a solid curdled layer at the
bottom of the tin and a clear aqueous layer on the top.

It can also denature some of the resins in the paint so that they will
never quite cure properly or with the same surface finish lustre as the
original paint. A problem when using it to touch up. You often find that
paint on the walls has faded slightly compared to that in the tin.

--
Regards,
Martin Brown