Batwister, will this whet your appetite?:
"The extraordinary story recounted in this book opens at a market junk stall in Yorkshire with the discovery, quite by chance, of a family collection of several hundred Victorian and Edwardian [glass] photographic negatives." That's the introduction on the dust jacket of a book I picked up in a secondhand bookshop a year or two ago. It's titled "A Richer Dust, Echoes from an Edwardian Album" by Colin Gordon, who found the boxes of negs in 1975, cobbled together some kit to print them and did a heap of research into the family and the photographer. It's a fascinating read, published in 1978 by Book Club Associates. You might be able to track it down through your local library. I see there's a copy for sale at AbeBooks.co.uk. Google throws up more.