Re: Coating Carleton Watkins
Actually it's buffered alkaline board purported to be bad for albumen. Non-buffered board is recommended. I've got some very old albumens that have been attached to regular vintage acidic cardboard stock all along (not corrugated), using old mucilage glue, that are still in perfect condition.
Re: Coating Carleton Watkins
I believe it's the Indian Canyon trail which was used to hike to the top of the falls to at least 1878 when Watkins revisited the same area that year and no doubt until the new trail was built on the opposite side of the fall. The trail was mentioned in Whitney's The Yosemite Book published in 1868 with photographs by Watkins. Here is an account of a 2013 accident on that trail so it's still being used: https://www.nps.gov/yose/blogs/india...and-rescue.htm
Thomas
Re: Coating Carleton Watkins
very good read on the history of Albumen is: The History, Technique and Structure of Albumen Prints by James M. Reilly Research Associate, School of Photographic Arts and Sciences, Rochester Institute of Technology, One Lomb Mem. Drive, Rochester, N.Y. 1k623 at: http://albumen.conservation-us.org/l...eilly1980.html