« Reply #10 on: Friday 19 October 18 17:02 BST (UK) »
I could be that thick mount/backing board -I've forgotten what it's called. It's composed of a soft matted compressed card material sandwiched between two thinner sheets of brown thin card 
It's not MDF - pre that!
I really don't think you Gadget

I know the type of compressed card that you are describing, I have a few enlarged and over-sketched images on that kind of card.
Carol
CAPES Hull. KIRK Leeds, Hull. JONES Wales, Lancashire. CARROLL Ireland, Lancashire, U.S.A. BROUGHTON Leicester, Goole, Hull BORRILL Lincolnshire, Durham, Hull. GROOM Wishbech, Hull. ANTHONY St. John's Nfld. BUCKNALL Lincolnshire, Hull. BUTT Harbour Grace, Newfoundland. PARSONS Western Bay, Newfoundland. MONAGHAN Ireland, U.S.A. PERRY Cheshire, Liverpool.
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