Crawford, William. The Keepers of Light: A History & Working Guide to the Early Photographic Processes by William Crawford.

Morgan & Morgan, 1979. Scarce hardcover edition, near fine, illustrated paper over boards, not issued with dust jacket. Custom made polyester jacket. After an excellent introductory history section of more than 100 pages, illustrated with color plates by Julia Margaret Cameron, Joseph Keiley, Edward Steichen, Hill & Adamson, Charles Negre, Henri Le Secq, William Henry Fox Talbot, J.J.E. Mayall, William Notman, Alfred Stieglitz, et al., Crawford provides detailed instructions and discussion of 19th and early 20th century photographic processes, including Salted Paper, Ambrotype, Platinum, Palladium, Kallitype, Carbon, Carbro, Three-Color Carbro, Gum Dichromate, Oil, Bromoil, Photogravure, and Collotype, as well as Color Separation and Conservation and Restoration. Also includes chapter, Early History of Photomechanical Printing, with discussion of Heliography, etched Daguerreotypes, Photogalvanography, Gravure Heliographique, and Woodburytype. Essential reference on this topic. Summary:

The Keepers of Light: A History & Working Guide to the Early Photographic Processes by William Crawford (published by Morgan & Morgan in 1979) is widely regarded as the definitive reference manual and critical history bridging 19th-century photographic technology with modern alternative process printing.

Key Summary & Highlights

• Dual Structure: The book is uniquely divided into two complementary parts: a comprehensive cultural and technological history of photography, followed by an step-by-step practical working manual for darkroom artists.

• Syntax of the Photographic Image: Crawford introduces a framework for analyzing how technological limitations—such as tonal range, grain, sharpness, and spectral sensitivity—dictate the visual aesthetic or "syntax" of photographs from different historical eras.

• Historical Survey: The first half traces the evolution of photographic medium technology from the daguerreotype and calotype through wet-plate collodion, carbon printing, platinum/palladium, and early photomechanical reproduction methods.

• Practical Darkroom Manual: The second half provides precise formulas, chemical safety protocols, emulsion preparation, and practical troubleshooting guides for artists looking to recreate historic non-silver and handmade processes, including cyanotype, salted paper, gum bichromate, platinum/palladium, and photogravure.

• Enduring Influence: Considered an essential bible for conservators, photo-historians, and alternative process photographers, Crawford's work played a central role in reviving interest in historic printing methods during the late 20th century.