Mixing a General Purpose Collodion

Here is a good general purpose collodion formula for making ambrotypes or negatives. The total volume is about 600 ml.

Pour into a 32 ounce bottle:

  • 190 ml Ethyl Alcohol (180 proof)
  • 150 ml Diethyl Ether (anhydrous)

In a 50 ml beaker, place:

  • 4 gm Potassium Iodide
  • 3 gm Cadmium Bromide
  • 4 ml Distilled water to dissolve the dry chemistry.

When completely dissolved, add this to the alcohol and ether mixture and shake:

And then, thicken with...

  • 250 ml plain collodion, USP

Cap the bottle, and shake to thoroughly mix. Let stand for a day or two before use. The cadmium bromide is generally clumpy and cakes up when it first gets wet. It may take a little time to completely dissolve. If necessary, use a glass rod to break it up into smaller pieces or gently heat the solution on a hot plate while constantly stirring the liquid in the beaker to speed the process along.