First, a plate of aluminum is coated with collodion, which is a sticky substance that adheres to the plate. This serves as the photographic emulsion that the image will live in. The plate is then put into a solution of silver nitrate. The different salts that are in the collodion react with the silver to create light sensitive silver crystals which remain suspended in the collodion.

After this step the plate is basically a piece of photographic film, or darkroom paper.

The sensitized plate is then put into a plate holder and the photo is made! This part of the process is just like shooting a normal photograph, with the main difference being how sensitive it is to light. A tintype is roughly 6 to 10 times less sensitive than typical photographic film. Therefore, it needs a lot of light to make an image! In the studio, I use several high powered strobes to produce enough light in flash. When using natural light, it might take a few seconds of exposure to get enough light. That’s one of the reasons no one would smile in photos back when this was the only way to make photos. It’s hard to hold a smile perfectly still for long periods, so people would keep a neutral face. 

Another quirk of the process is what color of light it’s sensitive to. Our phones, cameras, and regular film are all sensitive to the whole visual spectrum of light. The wet plate process is only sensitive to blue and ultraviolet light. This has the effect of turning blues white, and reds black. This is why freckles will be far more visible, and clothes will change appearance.

After exposure, the plate goes back into the dark to be developed. The developer chemicals are poured on the plate and the images starts to appear. After a quick wash in the dark, it’s ready to come out into the light and be fixed. The fixing removes all of the unexposed silver crystals, while leaving the metallic silver of the image untouched. To simplify, the plate goes from a weird foggy negative image, to a positive image right before your eyes! I think it’s by far the coolest step of the whole process.

Once it’s fixed, it just needs a little time to dry before it gets varnished. It needs to be varnished for two main reasons. The first being protection. The collodion emulsion is very fragile and can be removed easily with a little friction. The second reason is aesthetics. The varnish adds a nice glossy finish to the plate. After all of that, the tintype is done, and as long as it’s not abused, will outlast all of us!