Hi - ive been busy lately trying a few things out. I had some lime putty kicking around so tried it on a bit of primed mdf with a bit of black to grey it off. It turned out OK but there was grit in it which caused streaks where it dragged.
I applied olive soap solution to it afterwards and trowelled it smooth to a polish.
heres the result
its intersting in that apart from the rolling grit streak lines it turned out reasonably well.
My observations are that the layers build up on one another and when dry an olive soap solution or wax water suspension are applied and either trowelled or buffed when dry - it gives the plaster a transluscency that reveals layers beneath & gives depth to the effect.
strangely the soap solution imparts a water resistant barrier contrary to what I would have thought but apparantly it reacts with the lime which changes its properties.