Asked this on the Messy Forum but believe I should have posted here

Any suggestions on how I can dilute metallic poster paint with out coagulation please. Water and oil have prove to be unsuccessful so far.

Have no experience with metallic casein.
In the normal casein (Plaka color) it holds a little longer supple with linseed oil or boiled linseed oil.
Another still can help extremely fat milk or milk cream.
That it all congeals and becomes solid you'll can not be avoided - but you make time.

An attempt is worth, I hope.:splat:

Thanks for that Linseed oil may well be worth a go