I guess that not writing for a spell is a sure sign that I'm researching my brains out! I've been busy combing the web for as much information and materials as I could get my hands on.
I've found a supplier of natural pigments, called, appropriately enough, Natural Pigments, that has nearly every renaissance era oil painting supply that one could hope for. I used the book I've mentioned as my reference point and listed, according to spectral analysis, the pigments Leonardo used on the Mona Lisa. I've bought raw pigments and ground them into paint using walnut oil as my medium. My sources tell me that Leonardo used walnut oil as well.
From the same supplier, I've gotten Italian Gesso (calcium sulfate). This will be mixed into a solution of hide glue and painted on the poplar panels. I've tested the gesso and oils on plywood panels of the correct size while I'm waiting for the real panels form the lumberyard back east. I've also tested a few formulations of emulsion grounds to use as an intermediate layer between the gesso and paint.
Recently, I did some research on possible glazing media for oil. Something which Leonardo might have used. One article I read about renaissance mediums included a tranlation from one of Leonardo's notebooks in which he specifies juniper resin mixed with walnut oil as a good varnish. Information I've found from various sources indicates that a resin mixed with oil and turpentine is a good general formulation for a glaze meduim. I have sandarac (juniper) resin on order along with unfiltered walnut oil to test as a possible glaze medium.
In addition, I've been doing as much scrutinizing and researching of the actual painting as possible. There are MANY subtleties that will be very challenging to pull off. Even though Lisa isn't wearing any jewelry, she is covered in silk veils. her hair, shoulders and upper arms are all covered with see-through, filmy material. Fine, fine black silk gauze. Did I mention that Lisa's husband is a silk merchant? All that silk is no accident...
This will definitely be challenging to paint!
The general sequence will be:
2 coats of gesso
perhaps a layer of emulsion ground
lead white priming
yellow ocher imprimatura
underdrawing with copper acetate
underpainting with burnt umber and white lead
glazing and finishing
Leonardo's technique was so refined as to be invisible. Conservators frequently mention the complete absence of brush strokes on Leonardo's paintings.
I'll be doing 2 copies simultaneously. One will be aged, and the second left to appear as the Mona Lisa may have looked new. Each will be framed, as the real painting is, in a flexible oak frame and a decorative frame.
I'll post pictures as soon as I've started!