I just finished researching a delightful book of Josef Sudek's Pigment Prints. I have always liked his work--a darkish pictorialism with a bent of odd--and when I saw this book I had our university library buy it (it is pretty expensive).
What I thought was a book about gum prints was in fact what I then thought was a book of carbon prints and then I think I have come to believe is really a book of carbro prints, if the author of the article in the book is correct--that Sudek exposed a bromide print, and then put the tissue in contact with it as per the quote below. So I think I am correct in defining this as "carbro" and not some other such process though I am not sure because the process was not named. I bet someone on the list can say for sure.
("Pigment prints were exposed onto BW paper and then pressed in contact with the carbon pigment tissue and the silver based image was transmitted "chemically" onto the carbon tissue." P. 15 Barbara Michaels, On Sudek and Music)
I like the fact that Sudek continually photographed the same window, simple subjects, and the light is mostly glorious in the work. It is a beautiful book if you have lots of extra money (about $40 on abebooks.com).
Christina Z. Anderson