Any framer worth their weight in gold should be conversant with conservation framing methods. Being able to tell the difference between Museum mount board and Conservation Mount card and when to use them is essential to their craft. They absolutely must know the best way to protect valuable works from environmental damage.
They should know when to include cross bars when making a stretcher frame and when to use either 3 mm or 5 mm glass. Depending on the size of the artwork, they will need to be able to advise when the weight of glass and backing will put too much strain on a slender moulding choice.
If the framer doesn’t know his/her Picasso’s from his Shane Clark’s, whoever he is, you should avoid their service! Leaving the framer with a valuable work of art when you are unsure they know its value, is asking for trouble. Most professional picture framers should have dedicated insurance cover for the storage of valuable artworks, but if in doubt it is best to ask.
The best way to test if your framer is to let him/her lead you. If they are confident with the language of all things visual, if they say things like, that colour is too cool, or overpowering, or make observations about the artwork, or ask you where it will hang, your framer probably knows a thing or two.
The good news in Cambridge and especially at Camframe is that the framers are all art school trained.