A transparent film of gun cotton dissolved in ether and containing potassium iodide spread over a glass plate negative. Wet collodion was sensitised on the spot and developed immediately. It gives high resolution of detail. Dry collodion was usually found to be less sensitive.

Biography
Born
1833
Died
1883
Nationality
Scottish
Thomas Rodger was a pupil and laboratory assistant to John Adamson. On the death of Robert Adamson, John Adamson urged the sixteen-year-old Rodger to set up his own studio in the city. He had a precise approach to the chemistry of photography which earned him success at exhibitions and competitions around Scotland. Having begun as a 'calotypist' in 1848, he later moved on to the collodion process. Sadly, his glass negatives were smashed when, after his death, his studio closed down in the early 1900s.
Glossary terms
Collodion