Contrast control in Wet Plate Colodion process

Plate on the left was normaly exposed (5 seconds) and normaly developed (18 seconds), plate on the right was exposed for 10 seconds and developed for only 8 seconds.

Few days ago I’ve finished a bacis collodion workshop and part of my workshop is a demonstration of contrast control in wet plate collodion process. I thought this might be intersting topic, so here’s a short post. Plate on the left is normaly developed and exposed and plate on the right is overexposed and underdeveloped. As you can see the middle tones are about the same, but the plate on the left has no details in highlights. This is usual push / pull process that is very well known in film photography and the same goes for wet plate collodion process.

Have you ever heard that a collodion mixture becomes more contrasty with aging? Well, that’s merly a false myth. Collodion becomes less sensitive and if a photographer is using the same exposure times with old colloodion, the plates are in fact undrexposed and on top of that overdeveloped, so of course the end result is much more contrasty then it was with fresh collodion, but if you want to have low contrast with old collodion, you only need to overexpose and underdevelop! So the cause of contrasty plates is not the age of collodion, but underexposure and overdevelopment.

This is what I’ve learned from Mark Osterman.

Here are two more plates that I’ve manages to make a reproduction of.