I'll confess that I'd have to run for a book
for 5- and 6-spot mica
condensors/capacitors. Same goes for silvered mica.
Gawd, it's been years since I saw one of those. And yes, I'd have to look
them up. IIRC you read one row of dots one way, the other in the opposite
direction. I could still do (at least the capcitance) of a Mullard C280
though.
One thing I did find curious was that in one table of colour codes, it
claimed things like a violet tolerance band/dot meand it was +/-7%. Was
that ever used?
-tony