Camera Emulsion

Most of the easy emulsions are to slow to be very useful in a camera, but it would be very useful to have one that you could shoot with. Since there is no published recipe that I know of that is suitable for the particular purpose of shooting in a movie camera, this project sets out to create one, and to understand the principles involved so as to be able to advance on it.

Right at the outset, let me give enormous credit and thanks to Denise Ross, whose wonderful website, http://www.thelightfarm.com/(external link), gives the most comprehensive and well written compendium of existing knowledge and carefully reported results from the world of still photography emulsion making that's out there. She's amazing, and sets a standard for openness and systematic work. Thanks, Denise!

As I starting point, I'll be using a slightly modified version of a recipe from Denise Ross, published on her website here:

http://thelightfarm.com/Map/DryPlate/Recipes/TheBasics/TheBasics.html(external link)

HMFI Camera Emulsion starting point

Start by making the necessary stock solutions (1% KI). Then, make up these three solutions:

Solution A: Salted Gelatin
Inert Gelatin 2.5g
Distilled Water10mlcold

Soak the gelatin in the water for about 30 minutes. Meanwhile, dissolve together in a separate small beaker:

Distilled Water13mlroom temp (~20°C)
Potassium Bromide7.0g
Potassium Iodide, 1% Solution0.75ml*

  • The original recipe calls for 15 drops, but in the interest of repeatability I substitute ml according to the official metric definition of 1 drop = .05ml

Add this salt solution to the gelatin solution.

With slow stirring, heat the salted gelatin in the 41°C waterbath for 1/2 hour.

Solution B: Ammoniacal Silver
Distilled Water10ml
Silver Nitrate6.0g
Ammonium hydroxide, 28-29%~5.5ml

The key to this solution is all in the mixing procedure! MAKE SURE YOU HAVE AN EXHAUST FAN OR REALLY GOOD VENTILATION BEFORE ATTEMPTING THIS! The concentrated Ammonia called for is NOT something you want to be around, and potentially injurious to breath!

Thoroughly dissolve the silver nitrate in the water. Under ventilation, with a dropper add the ammonium hydroxide slowly with stirring (Add a little. Stir about 15 seconds. Repeat.) A brownish-black silver hydroxide precipitate will form almost immediately. Continue to add and stir until the solution starts to clear a bit. Slow down the addition rate to a drop at a time and stir longer between additions. When you think all the little black flecks have dissolved, add one more drop of ammonia and stir thoroughly. It is important to avoid excess ammonia. The total amount of added ammonia should be very close to 6 ml.

Fill a closed stopcock buret staged to be ready to move into position over the beaker of salted gelatin.

Solution C: Plain Gelatin
Inert Gelatin5.0g
Knox Gelatin.5ml
Distilled Water 15ml

Created by Robert Schaller. Last Modification: Wednesday 29 of January, 2014 17:43:50 UTC by Robert Schaller.