I have recently discovered an interesting site "Watch the Birdie" which contains information on Victorian Photographers - at least some of which come from Hertfordshire. It is run by Christine Hibbert and describes itself as follows:
I’ve been collecting cartes-de-visite photographs for some years now. These are small photographic images from the second half of the 19th century and are a window on the world of Victorian society.My main interests, however, are the names and studios of the photographers who produced these images. Therefore I have collected data from all over Britain relating to 19th century photographers and set them out in alphabetical order, with open-ended dates where known. Trade directories are my main source for these dates, as is census material.The backs of c-d-vs are minor works of art in their own right. They show name, address and services offered by the studio and can be invaluable if there was a photographer in your family tree, if you need to date an old family photo or if you just appreciate graphic design. All the names recorded in the main lists relate to c-d-v photos in my collection.I hope to add more of these images, backs and fronts, in the course of time and hope you will venture into the world of our 19th century ancestors, when the photographer said ‘Watch the birdie’.