To obtain the "wet stone" effect on a moderately absorbent surface, one coat of varnish is sufficient. If the surface is porous, a second coat of varnish must be applied 1-2 hours after the first coat has dried.
If there are rusty areas of metal on the ceiling or walls, they must be covered with enamel. If this is not done, the rust will appear after the puttying.
To obtain a high-quality and beautiful varnish coating, it is necessary to maintain absolute cleanliness in everything, including clothing, during its application. Ideally, you should wear special disposable shoe covers on your feet, and a disposable coverall with a hood made of non-woven material on your body. If you do not have either of these, use any clean clothes from which threads, lint, etc. will not fall. Put a hat on your head or tie a scarf (any hair that falls on the raw varnish can ruin the whole picture!). If you do not have shoe covers on your feet, varnish the parquet in clean socks / stockings or barefoot.
The "Flower of the European Union" is a symbol of high quality and care for the environment. Trust the flower!