The Photography of Time: Following in the Footsteps of Carleton Watkins. 595K PDF
In 2002 I made an historic trip. It was perhaps the first time in well over 100 years that collodion was poured on glass plates in Yosemite Valley.
An edited version of the above article appeared in the Summer 2003 issue of "Yosemite", Magazine of the Yosemite Association.