Lea Formula 3 – Portrait Collodion Results

Over the past 7 months I have been testing several different collodion formulas.  This is the first set.

This is Lea Formula 3 – Portrait collodion, from “Manual of Photography” by M. Carey Lea

It is a slow ripening Cadmium based formula.

At one day it is unusable.

At 2 months it’s almost usable.

At 5 months it’s nice.

At 7 months it’s nice and maybe a bit faster.

The advantage of this formula is that once ripened it’s extremely stable.  It is said to last for 12 to 18 months or more.

Disadvantage – It’s cadmium based and it takes 5 months to ripen.

I have made a lithium based version of this formula that hopefully will ripen slightly faster and last as long.

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At 7 months you can see that Lea Formula 3 is still a nice yellow color. A hybrid using LiBr in place of CdBr2 is aging faster.



The intent of this blog is to test various chemicals and techniques used in the wet plate collodion process.  Reality is that everything has already been done back in the late 1800’s, so most everyone today is just reinventing the wheel.   That said, we can duplicate what has been done to confirm and document the outcome.  My current interest is in the collodion formulas from M. Lea Carry.  I am currently testing several of his formulas, along with some cadmium free formulas, and will post the results once I have a a few more sets of plates finished.  To try and make the testing as consistent as possible I developed a standard shot that can be duplicated plate after plate.  It uses CFL’s as a light source, which give a consistent light source, but I will have to develop something outside to test natural light.  Controlling the sun will be a bigger challenge!

Standard Shot Rig
Standard test shot rig.

This is the rig I came up with for the standard shot.  It uses my Speed Graphic with 5″ Gem Petzval.  This photo is still in the development stage.  I added an extra light at the top and various subjects including a grayscale and a color scale.  Using a stopwatch I have been able to get consistent plates from this set up.  I have already seen some interesting differences between the formulas, and am excited to see a couple as they age.

First set of test plates.
First set of test plate.

Other things I would like to study are fixers – KCN vs Rapid Fix and Hypo.  The thought is that KCN gives a warmer image, but developer & development time may have a greater influence.

More to come…