I see collodion as the stinky volatile friend at the party who makes it interesting, but potentially explosive if they drink too much. Collodion is mixed with iodide, bromide or chloride. Collodion is used for it’s properties as a base that sticks to the glass, a gel that is the canvas for the image. It dries into a clear film once it has been through the developing process and is a combination of pyroxylin (nitrocellulose, explosive and the original base for gun cotton when undiluted), alcohol and ether. A heady mix, it’s best to avoid breathing in it’s aroma.
These two images were taken with different batches of collodion on the same day. I found that the newer batch of collodion actually created a more contrasty image (they were similar exposures and light) all the images created from the second batch of collodion had a higher contrast. So, I asked myself, why is this? I may have been less accurate in my measuring out the iodide and collodion, or I may have put in slightly more tincture of iodine, which boosts contrast or it may just have been the age. This just goes to show, very minor differences can change the quality of the image, yet another fascinating variable to watch out for that can change the whole feel of an image.