First make sure it is well sanded
after that clean all with water and 1 cup vinger make sure they are free of all dust
Now take regular primer flat (mat ) I think in the USA and mixed with waterit so that it's very thin almost water like , then with a cotto cloth apply to the item you want. This can be repeated until you get the effect you want usually 3 coats.
( can be mess best if the beams are not on ceiling already ):thumbup:
At the paint store u must make sure you get paint that can be thinned with water :thumbsup:
Hope it is clear if not let me know and let me know how you like this , in addition try it first on a piece of pratice wood then u will see if this is what your wanted.
Dutchgirl in Holland