Collodion process

Abstract: The wet collodion process was the first successful photographic negative process. The tone and detail reproduction of both negatives and prints are remarkably good. There are a lot of collodion plates still in existence, but detailed knowledge of how the excellent image quality was achieved has been lost. The Institute ofApplied Photophysics in Dresden, Germany, harbors the photographic work of the German pioneer Hermann Krone (1827-1916). He became prominent after using the wet collodion method for landscape photography in 1853. It is extremely difficult to make satisfactory reproductions from those historic negatives on contemporary photographic materials or to digitize the old pictures. The aim of the present work is to gain knowledge of how to reproduce satisfactorily the tone and detail of wet collodion negatives and prints on modern materials. To gain more knowledge of the process, wet collodion layers were poured and then investigated using tools of modern imaging science. Sensitometric curves and relative spectral sensitivities were investigated for a range of emulsions with varying iodide-bromide ratios. Granularity noise and resolution were measured by means of a high-resolution CCD microdensitometer.