Makers and players who have seen them know that the instruments made during the "golden period" between 1550 and 1750 in Italy have a unique look. It's often attributed to the varnish, but it seems to have more to do with the ground; something they put on the wood before varnishing. I've used many different grounds some commercially bought and some cooked up in the shop, and it seems like every instrument gets a different treatment. Someone once described this ground as having the look of a soft light coming from the wood under the varnish. I've noticed that sometimes this light is on and sometimes it isn't. I'm not sure if there was something different about the ground or just the way the wood itself reacted to it, or maybe the way the light was hitting the instrument that day. The closest I've come to that look was when I rubbed some oil varnish directly into some aged and darkened spruce and maple. However on my last visit to the Shrine to Music Museum, most of the instruments did seem to have a golden yellow color applied under the varnish. The exception was the Stradivari Harrison violin. I've tried gumboge, coffee(it tastes good too), commercial preparations, potassium silicate and sodium silicate and I'm thinking about trying the Fulton Propolis soap. Karl Roy told me that before Sacconi died he told him that he had changed his mind about potassium silicate and thought it was washed linseed oil and a very small amount of bees wax(sounds like grandmas formula!). I'm just now finishing a cello and I'm really tempted to try it. I think the varnish researcher Gary Bease believes they just put an oil varnish right over the wood and that they either put the instruments in the sun long enough to tan them, or the wood darkening was just something that happened over a period of time. I've always found it hard to believe that they could have kept the instruments off the market long enough to tan them. They had to eat, same as us. Although when Stradivari died I believe there were still 70 or 80 instruments in his shop, but I don't think most makers would have had the luxury to make so many and hold on to them. Sometimes I'm not even sure that it matters,or that we can't come across something entirely new that looks as good or better. Yet when I see an authentic example from this period I find them incredibly beautiful. Anyone want to share the secret, or their favorite sauce?