Lime to whitewash
Lime in addition to being a binder can be used diluted in water as a paint to whiten. p>
It has strong fungicidal properties and does not create a vapor barrier and therefore lets the walls breathe.
Can be deactivated with casein to improve adherence properties.
It can be pigmented to get various colors.
It can not be applied on walls previously painted in oil or with silicates.
A minimum of 3 coats are required for a new coating, while 2 coats of color can be used for already painted walls.
Natural resins are used to protect wood and are made from the secretions of some plants.
Of course they are transparent and are soluble in oil or alcohol.
They are also used by luthiers for painting musical instruments.