Sincere appreciation is due my long-time colleague in scanning electron microscopy, James T. Thrall Jr., who volunteered his time for the analysis of the crayon photograph described in Appendix II; to Leon Jacobson, who introduced me to the fascination of historic photographs; and to the late R. Gilliam Rudd for his many practical lessons on the right way to copy photographs.

I am much indebted to Dr. M. Susan Barger for furnishing reprints of many of her papers; they are the definitive work on Daguerreotypes and also on many other contemporary processes.

I am most grateful to Nancy Burgess for donating part of her collection of photographs, for loaning her copy of Estabrooke when I was unable to obtain a copy, and for her enthusiastic support during this project.

I owe a special thanks to Susan H. Abbey, retired Archivist, Sharlot Hall Museum, Prescott Arizona, who encouraged my writing for more than ten years. She made the ultimate sacrifice: she read and edited an early manuscript.

I am particularly indebted to Richard Pearce-Moses for a copy of the Smithsonian Archives Draft Photographic Thesaurus, which has since been included in the Art & Architecture Thesaurus, 1994 edition, published on behalf of the Getty Art History Information Program.

Many other friends made my efforts much pleasure. I send apologies to those I have accidentally omitted to mention. The mistakes are all mine; the generosity theirs.

Many kind and helpful people in the following libraries and symposia made research a pleasure during more than ten years:
  1. Bar Harbor Historical Society, Bar Harbor, Maine
  2. Canadian Archives, Ottawa, Canada
  3. Gernsheim Collection, University of Texas, Austin, Texas
  4. .Institute For Creative Photography, and the Library of the Department of Engineering, University of Arizona, Tucson
  5. International Museum of Photography at George Eastman House, Rochester, New York
  6. Ohio Historical Society, Columbus, Ohio
  7. Rochester Institute of Technology main library, Rochester, NY
  8. Seward House, Auburn, New York
  9. Syracuse University: E. S. Bird Library, Syracuse, New York
  10. Wilmington Historical Association, Wilmington, North Carolina

PhotoHistory Symposia, International Museum for Photography at George Eastman House, 1997, 1991, 1988, 1985, 1982
International Symposium, The Stability and Preservation of Photographs, Ottawa 1982
Arizona Paper and Photograph Conservation Group, Tucson 1989

"I have read all of some of the books, and some of almost all of them, and the rest I'll get to, one of these days"...

Bookmark inscription, Prescott Public Library, Prescott, Arizona.