We're often asked what the differences are between the different collodions we offer, so time for a quick test!

We mixed up a total of 10 different collodions, most of these we offer through our shop, but a few are historical or experimental recipes. The formulas for most of these can be found on the formulas page of the website.


100ml of each collodion was mixed and left to settle for 5 days, this should be sufficient time for each recipe to ripen, we'll do another test in a few months to see if there's any difference.

A quick studio setup was created to try and cover a full range of colours and tones, greyscale and colour swatches were also included. 

A 5x4 tintype was taken using a Sinar 'P' camera on a studio stand, a modern 150mm Sironar lens was used. Lighting was via a bank of flourescent bulbs in a square modifier (softbox with no cover) placed off to the right of the scene, a reflector was used on the left to kick a little light into some of the shadows.

All plates were shot in the same session, a plate was coated, sensitised, exposed and developed  and the process repeated for each collodion, one after the other over the space of an hour so as not to introduce any external factors (eg a rise in heat or movement of the lights).

The silver bath was tested to have a SG of 1.070 and was sitting at 20 degrees throughout the shoot. 

Most steps of the process were timed as follows:

Sensitisation of the plate: 3 minutes 
Exposure: 8 seconds @ f11
Development: 15 seconds

The plates were developed in our standard wetplate developer (Ferrous sulphate, ethanol, acetic acid & water), they were then fixed in Kcn, further plates were also shot and fixed in Hypo and rapid fix to see what the difference was.

The exposure time was based upon test exposures using our Old Workhorse formula, this is our go-to collodion for most things we shoot personally so it made it easier to estimate exposure.  As the exposure time was consistent for each shot the results also give an indication as to the speed of the collodion, those that are slower than old workhorse will appear darker, those faster will appear overexposed.

Plates were then scanned in an Epson V700 flatbed scanner (apologies for the dust!), alongside each plate was a grey scale chart which was used to select the black, white and midtone values when scanning, this colour chart was then checked again in photoshop to ensure all of the images look as realistic as the original plates. Obviously this will only be of real value on a calibrated monitor.


  1. New guy
  2. Old workhorse
  3. Reh's Lithium
  4. Ambrotype with Zinc
  5. Keskino 3 salt
  6. Disderi Summer formula
  7. Lea's landscape #7
  8. Poe boy
  9. Cadmium free
  10. Quick clear Lithium

New guy

This is one of the most popular collodions that we sell, especially to people just starting out. It doesn't need to ripen long before consistent results are achieved, in terms of speed it's medium to fast.

Old workhorse

Old workhorse was originally formulated by John Coffer in the USA, it's marginally slower than the New guy but gives a more pleasing range of tones in my eyes (it's all very subjective!). This is the collodion we tend to use ourselves when shooting in the field.

Reh's Lithium


Reh's is a collodion based upon lithium salts instead of the more common Cadmium compounds. As such it's seen as a safer alternative. It gives a good tonal range and is very similar speed wise to Old workhorse. It does contain Potassium which means that it does take longer to settle and will need to be decanted or poured very carefully out of the bottle.

Ambrotype with Zinc

Another historical recipe which uses Zinc salts, in addition to Cadmium. The plate displays some very good midtones on the colour chart but is otherwise very similar in overall look and feel to the collodions above.

Keskino 3 salt

Keskino 3 salt is a little faster than Old workhorse and similar collodions above.

Disderi Summer formula

André-Adolphe-Eugène Disdéri was a famous French photographer best known for popularising the Carte-de-visite in 1854. He created a number of different collodion formulations, most notable are his collodions for shooting at particular times of year. We mixed up the summer blend for this test. It is an unusual formulation in that it contains elemental Iodine and as such should require no ripening, It also uses very little collodion in the formulation, almost half of that found in others so is very thin and fluid to apply. The overall effect is very good, nice midtones and brighter whites without much of the yellow tint seen in others.

Lea's landscape #7

Lea's landscale #7 developed by Carey Lea is another very popular collodion, in the field it seems to allow for much shorter exposures than other collodions, it is one of the most potent blends chemically with both Cadmium Iodide and Cadmium bromide being used in addition to 2 Ammonium salts. It requires longer ripening than a lot of other formulations but has a much longer shelf life with little in the way of darkening over time.

Poe boy

Poe boy has a good following amongst people that don't like to use collodion formulations that contain Cadmium. It requires time to settle due to the large amount of Potassium salts used which are only partially soluble. It gives good speed and a pleasing tone to the image a little more neutral colour wise than some of the cadmium containing collodions.

Cadmium free

The cadmium free collodion is noticably the slowest collodion that we tested, great if you're shooting on a sunny day and want to slow your exposures down a little. It requires quite a long time to settle before use, the 5 days we gave this sample combined with moving it around the darkroom a few times did stir up some of the sediment which manifested itself as a few marks on the plate itself, however there's no doubt that once settled properly that this is a very capable collodion.

Quick clear Lithium

This quick clear collodion is an experimental blend which does away with the Potassium salts found in Reh's collodion, it has no sediment which makes it much easier to use. It performed very well and is quite fast in terms of sensitivity but we did experience a few marks on the plate for this test which we've yet to identify.

In conclusion

Overall we were actually quite surprised about just how similar a lot of the collodion mixes are, with the given exposure based on our knowlege of what we normally shoot at in the studio every single plate gave good overall results, not one of the plates shown above was reshot during the test. Sure, the exposures could be adjusted based on the recipes and we may try and do this, but I've a feeling we'll find that the plates all look very similar. 

So how do you choose a collodion mix to use? If you're shooting outside in bright sunlight and struggling with exposure then select a cadmium free collodion as there are slower, if you're shooting in less light then try the Lea's landscape #7. For anything else pick one you like the look of and stick with it! 

We've started shooting more test plates with these collodions using different developer blends and different fixers so stay tuned for the next blog post.