I live in Italy, so my expressions for techniques and materials may differ from those normally used in English. I apologize if this sometimes leads to confusion! Since the debate on preserving traditional skills is close to the hearts of many I wanted to clarify why I use the term "lime putty" painting:
Up until about 50 years ago decorators here were able to slake there own lime ( slaking being the term used for describing the process of obtaining putty) My colleague still remembers as a young painter going to a deposit to do this ( n.b. only a while back decorators here often made their own paintbrushes!) Fortunately now the deposit sells the putty in sacks. Point being; If you wanted to paint with lime, you got putty.
Recently in Italy and I presume all over the world, products are available on the market that are manufactured as lime-paint or wash and are ready to use, some brands are available even ready-tinted. Without discussing their validity, those who were trained in the method of using lime putty as a bases for making up their paints for grisaille decoration, tend to continue to do so. The reason for this is simple, the product performance and result is different. We must necessarily use the product that best responds to our needs. So if you buy a brand product and it works well for you, then you have your tool. I too, use most materials for decorating, depending on what I have to do or what has already been used on the plaster. Linguistically however, the only way I have to explain the method I use when propositioning lime, is to say "I use LIME PUTTY" because if I were to say lime-wash in Italy, chances are I am talking about using a brand manufactured lime. Hope this has cleared up the misunderstanding!