Good evening all! This is for those people like me who have been unable to find an explicable answer to the "doublet stiffener"!
I'm still not satisfied that 'Spectrum' is the answer because of the way the clue is worded - had it said "...stiffened by a doublet", then it would have made slightly more sense (in my opinion.)
Anyhoo... I emailed the FT this morning, included my phone number, and have yet to hear word one by way of a reply...
...I'll keep trying to resolve this & will of course pass on any information I might receive!
Don't forget that Tuesday 18th is the effective closing date (for Wed 19th draw), so it's not urgent as yet...
King: I am afraid Gozo has thrown us a wicked pitch here. I looked at opal doublet to see if there was a stiffening material. I have seen onyx SHEET CUT and glued to the back of an opal to increase its colour. They call that an opal doublet in lapidary work.