A Manual of Photographic Chemistry, Including the Practice of the Collodion Process · T. Frederick Hardwich — chapter 9 of 60 · ~12 words · public domain
Collodion Photographs as Positives and Negatives, with the distinctive peculiarities of each.
A Manual of Photographic Chemistry, Including the Practice of the Collodion Process · The Wunder Library — complete classics, free to read, with narration.