A note about wet collodion...
Collodion is made of gun cotton dissolved in ether, and then diluted in alcohol or more ether to make a sticky mucilage that can be poured onto a sheet of "tin" or glass and swirled around until it covers the surface in a thin, even film. The plate is sensitized by being dipped into a bath of silver nitrate solution before the collodion dries. While wet, it is loaded into a film-holder, put in the camera and exposed. Then, again still wet, it is processed and the image, a positive if made on metal or opaque glass, or a negative if made on clear glass, can be seen.
In the mid- to late 1800's, photographers travelled with a tent or a horse-drawn wagon in which the daylight-sensitive plates could be coated and then processed in relative darkness. They made images under the most challenging situation and in all kinds of weather. Collodion is highly affected by changes in heat and humidity and historical images show all kinds of resulting artifacts, dust, insects and peeling collodion. Given the time-consuming process and the cumbersome nature of its equipment, is a miracle that many of those photographs still exist. Images on pieces of glass up to 18 by 22 inches were packed in wooden crates in straw, and transported through deserts and forests on the backs of pack animals. Even if the bottles of volatile chemicals didn't explode in transit, the pour was even, the exposure adequate, the processing successful and the plate didn't peel in the drying, it was still touch and go whether they would make the journey home without getting broken.
Wet collodion needs a long exposure and therefore is not good at freezing movement or for use with hand-held cameras. It is the most sensitive to the blue part of light and has a tonal range that is unlike modern pan-chromatic films. This gives rise to the characteristic white skies of Civil War images and the dark rendering of reds. It was the first widely-used commercial photographic process for making repeatable images.