For over thirty years, from the 1850s to the mid 1880s, the wet plate collodion process was the most commonly practiced photographic method around the world.

The Ambrotype - Collodion Positive on Glass

The Ambrotype process (from Greek “ambrotos”, “immortal”) was invented in 1854 by a 19th century American photographer and inventor. The Ambrotype is a thin or underexposed collodion negative on a glass plate. When backed with black varnish, paper or cloth, the thin negative turned into a positive photograph. This technique was popular through the 1860s.

Ferrotype/Tintype - Collodion Positive on Metal

The Tintype, also called  “Melainotype” and Ferrotype, is a photographic process invented in the United States in 1856. These photographs became the most common form of durable and inexpensive images made during the Civil War. The Tintype was very similar to the Ambrotype, except a blackened piece of sheet iron was used, instead of glass, as the base of the photograph. The word “tin” is kind of a misnomer; it refers to the image as being "tinny" (meaning cheap/inexpensive) photograph, rather than the material it is made on. Today, black anodized aluminum is commonly used to make “Alumitypes”.

A brief description of the making of an ambrotype - a wet plate photograph on glass:

The clear glass needs to be backed with something dark, for the final image to appear positive.



1. Clean a glass plate with a home made cleaning paste. (You can clean several at a time.)

2. Set up your camera on a tripod, focus it, and try to guess an approximate exposure time. 10–30 seconds is perfectly normal.

3. Take your plate holder, your clean plate, and get into your darkroom (mobile or stationary).

'Flowing' and sensitizing

4. In the darkroom, pour collodion over the plate, making sure it covers its entire surface. This is called flowing the plate, and takes practice to do well.

5. When the collodion has set (15–30 seconds) lower the plate into the silver nitrate solution tank. Close the lid so that no light can enter.

6. Wait 2-3 minutes.

7. [With Safelight on] Open the silver nitrate solution tank, remove the plate and load it in the plate holder.

8. When it is safely in the closed plate holder, walk to the camera.

Making the exposure

9. Put down the plate holder, double check the focus on the camera, and close the shutter.

10. Affix the plate holder to the back of the camera.

11. Remove the dark slide.

12. Make the exposure by opening and closing the shutter. Anything from 1 second to 1 minute is normal, depending on the conditions.

13. Insert the darkslide.

14. Remove the plate holder, and walk to the darkroom.

Develop and fix

15. [With Safelight on] Open the plate holder and remove the plate, holding it carefully in your hand. Place the plate holder out of the way.

16. Pour developer on the plate, using the least amount possible, but covering the whole plate. This also takes practice to do well. Develop for about 15 seconds.

17. Stop the development by submerging the plate in water, or by pouring water on it gently and evenly.

18. When the development is stopped, the plate is no longer sensitive to light. [Safelight off]

19. Submerge the plate in the fixer. Fix until the plate clears, about 15–45 seconds. Now you should have a positive image on the plate.

20. Rinse in water baths, at least 20 minutes.

21. Place plate in drying rack.

Varnishing the plate

22. When dry, heat the plate over an oil lamp. Don’t overheat it. If you can’t hold it in your hands, it’s too hot.

23. Hold the plate in your hand, keeping it perfectly level, and pour the lavender varnish on the plate. Make sure that you cover the entire plate. Pour off excess varnish into a separate drain bottle

24. Hold the plate by the edges, and gently heat the plate over the oil lamp. This speeds up the drying of the varnish. Don’t overheat.

25. Let the plate dry completely in a dust free environment. This can take a day or two.