I have tried light bulb test into Spruce amd Cedar guitar I owned and Spruce do let the light passed through and Cedar didn't.
My question is, is this test sure work on all Spruce vs Cedar? Any possibility light don't pass through certain type of Spruce on a classical guitar?
I am asking this question is because some old guitar's top, due to aging finishing look very cedar but in fact a spruce top.
Antonio Picado Model 60 Spruce 2017
M.Sakurai No.5 Cedar 1976