We must, therefore, first know what the failures in collodion negatives and positives are.
<Context ref.>Chapter 44. Imperfections in Collodion Negatives and Positives, and their Remedies [En línia]. [Consulta: 7 juliol 2005]. Disponible a: <http://albumen.stanford.edu/library/monographs/sunbeam/chap44.html>