Wet plate collodion
In a nutshell, wet plate is a very tactile and immediate process. It’s “limitations”, limited sensitivity and speed of the emulsion actually give the resulting images a unique allure, which transform the subject whether still life or portrait.
My abridged version of the tintype process, including my observations :
The substrate is the defining factor of the name of the finished piece. If aluminium engravers plate or tin is chosen it will be a Tintype, if glass is chosen it will be an Ambrotype. Just to confuse matters if perspex is chosen then it will be an Acrylotype…..
In any case the substrate must be perfectly clean before coating begins. This is where engravers plate scores, as it is simply a matter of removing the protective plastic film.
The plate is then flowed with collodion and allowed to dry partially. The aim is to get a smooth and imperfection free coating of collodion on the plate. The plate is then dried for about a minute until the emulsion takes a fingerprint, usually done in a corner of the plate. I find the fact that every plate then bares the makers mark to be a key aspect of the technique’s allure.
Once the plate is flowed the next stages, until fixing are time sensitive as once the collodion is totally dried it will be impervious to the chemistry and therefore no image will be formed. The exact time limit will be set by the atmospheric conditions, as a conservative guide you should aim to be in the fix bath in under ten minutes. The restricted timeframe affects the shooting process forcing decision-making to be more instinctive and immediate, or at least altering this part of photography from the norm.
The whole of the process so far can take place in the light as the collodion is not light-sensitive in itself. The flowed plate is now immersed in Silver Nitrate solution. The rest of the process should be carried out in safe-light conditions. After approximately three minutes the plate is removed from the silver bath, the back of the plate is cleaned of excess silver nitrate and then the plate is placed in a plate holder and exposed.
The emulsion is sensitive to the blue end of the spectrum of light especially to UV. As we don’t see in this end of the spectrum of light then the tintype reveals to us a different reality. Colours are rendered in unusual tones, blues are rendered lighter than usual and reds darker.
The plate is then developed, stopped and finally fixed, where the image is revealed as if by magic.
The whole of the above process minus exposure time and washing time should take less than 10 minutes, which compared to developing film and then printing makes it relatively immediate.
Although it may sound convoluted, in practice it is quite straightforward.
On reflection, the tintype I have found to be the Polaroid portrait of its day. I have found the unexpected immediacy of the process and the “wet plate gaze” ,an effect of the long exposure times certainly worthy of further exploration.
For a history lesson and a very comprehensive explanation of the process see here: