I had the privilege of working in a Jacobean house recently. I spent a good few weeks there working with some wonderful clients – I even had some assistance on some of the trompe l’oeil work from them! The beam I painted on here was to match some of the original beams in some of the other rooms. Timber like this really has a history – some of it is said to have been taken from ships of the time and a lot of it timber was knocking around following the dissolution of the monasteries. needless to say I painted woodworm in it and also hacking marks which I think were added originally for the traditional rendering to adhere to.
I painted them in acrylic and used varnishes as a glaze medium to speed up drying times. Something like this can be painted in just a few hours. If it was painted in oils it could take days waiting on the paint to cure before subsequent layers could be added.