Wet-Plate Collodion Process for Ambrotypes and Collodion Negatives Michael Mazzeo, instructor Lab Supplies: Safety goggles Latex or Nitrile gloves Dust mask Inexpensive Gram Scale (Accurate to .1g) 100ml Glass Graduated Cylinder 250ml Glass Beaker 25ml Glass Beaker Glass Funnels Glass Stirring Rod 2 – 4oz Glass Bottles with Ground Glass or Cork Stoppers 1 – 500ml Glass Bottles with Screw on Cap 4 – 250 ml Glass Bottles with Screw on Caps 3 or 4 Clean plastic trays (a bit larger than your plate size) Cotton Wool or Coffee Filters pH testing papers Glass Hydrometer Essential Chemicals and Ingredients: 1 pint Collodion USP 1 pint Ethyl Ether 1 pint 190 proof Grain Alcohol (95% Ethyl Alcohol, NOT Denatured Alcohol) 10g Cadmium Bromide 10g Potassium Iodide or Ammonium Iodide 10g Ammonium Iodide 50g Silver Nitrate 25g Ferrous Sulfate 1 pint Glacial Acetic Acid (99.9%) 500g Sodium Thiosulfate (Pentahydrate) 100g Gum Sandarac 4 oz Oil of Lavender 1 lb Whiting (Calcium Carbonate, Chalk) 2 gal Distilled Water (NOT Spring Water) 1 pint Lamp Oil (99% pure paraffin) Tools, Materials, and Equipment: Sheets of Clear Glass or Dark Stained Glass Glass Cutter Glass Pliers Whetstone (Sharpening Stone) Cork-Backed Metal 12" Ruler (larger if you’ll be cutting glass from larger sheets) Oil Lamp Dust Brush Upright Silver Bath with Dipper Camera, lens, and tripod Wet-Plate Holder for the Camera Basic Collodion Formula: This Collodion will produce excellent positives and soft negatives for printing on Silver Gelatin Paper or with processes that do not require dense negatives. These negatives can also be intensified for printing on Albumen, POP, and Salted Papers. 120ml Plain Collodion USP 60ml Ethyl Ether 90ml 190 Proof Grain Alcohol 3ml Distilled Water (NOT Spring Water) 1.5g Cadmium Bromide 2g Potassium Iodide* In a 500ml Glass Bottle add 120ml Plain collodion. To the Collodion, add 60 ml Ethyl Ether. Expect to see cotton-like substances form and dissolve as you cap the bottle and swirl the liquids around. Set the bottle aside. Measure 90ml Grain Alcohol and pour it into a 100ml or 250ml glass beaker and set it aside. Into a small glass beaker or test tube, pour 3ml Distilled Water. Add to it, 1.5g Cadmium Bromide, which will immediately cake up. Break it down with a glass rod and stir until it is completely dissolved. To this add 2g Potassium Iodide and stir until dissolved. Add this mixture to the alcohol and stir. This is the Bromo-Iodized Alcohol Solution. Slowly add this Alcohol solution to the Collodion-Ether mixture and periodically swirl it around as you add it. Cap the bottle and label it clearly. This Salted Collodion will be a pale straw color and over the next week or two will ripen to a deeper yellow or amber color at which time it will be ready for use. *To make a collodion that ripens more quickly, replace half or all of the Potassium Iodide with Ammonium Iodide. It will be ready to use almost immediately, but the shelf life will be much shorter. It is to be expected that a precipitate will collect at the bottom of this stock bottle and should be of no cause for alarm. Do not attempt to coerce the precipitate back into solution! Before use, the Salted Collodion must be siphoned or decanted into smaller bottles. Never should a bottle of collodion be shaken, stirred, or agitated before use; it will introduce air bubbles and precipitate into the solution which will appear on your finished image as tiny holes and imperfections. The Silver Bath: 90g Silver Nitrate crystals Distilled Water to make 1 liter The Silver Bath is a 9% Silver Nitrate Solution and the total volume is determined by the size of the tank used to sensitize the plates. After mixing the silver solution, pour some of it into a cylinder tall enough to accommodate your hydrometer. Read the specific gravity of the solution and make a note of it on the storage bottle for future reference. The specific gravity reading essentially tells us the strength of the silver bath. When the bath becomes weak from use, you will add enough silver nitrate to bring the specific gravity back up to this nominal benchmark. Next, read the pH level of the bath using pH testing papers, to determine it’s acidity. Make note of this also. A pH level of 2.5-6 is generally good for making positives and negatives, but positives will work best with an acidic bath and negatives with a more neutral bath. Before using the silver bath for the first time, it must be iodized in order to work properly. There are various ways of accomplishing this, but the most simple and effective way is to coat a plate with your ripened collodion, place it in the bath, and leave it there overnight or for about eight hours. The silver bath will now be ready for use. Each collodionized plate that is placed in the silver bath will infuse the bath with ether, alcohol, and organic impurities. The bath should be filtered after each shooting day to remove visible particles. After a while though, the bath needs a much more thorough cleansing. The traditional way, but not necessarily the most effective way, to cleanse the bath of impurities is by “sunning”. The silver bath is poured into a large wide-mouth glass jar and set in a sunny spot for a few days. The ether and alcohol will evaporate out of the solution and the sun will cause any organic matter to blacken and sink to the bottom of the jar. The clear solution is then siphoned off the top, filtered, and brought back to it’s original strength and volume by adding silver nitrate and distilled water. Another, possibly better, method is to simmer the silver bath in a glass coffee pot until half to two- thirds of the liquid evaporates. This will certainly eliminate any ether and alcohol from the bath. Allow it to cool, pour it into a tall bottle, add a few scoops of Kaolin (China Clay), cap the bottle, shake it up vigorously, and set it aside for a few days. This finely powdered clay clouds the bath and as it slowly settles to the bottom, it carries with it all the organic matter. The clear liquid is then siphoned out of the bottle, filtered a couple of times, and brought back to it’s original strength and volume. With either method, be extremely careful in handling the silver bath and in choosing where to let it stand. Developers: Developer for Positives: 100ml Distilled water 4g Ferrous Sulfate 6ml Acetic Acid 4ml Grain Alcohol 6g White Sugar Developer for Negatives: 100ml Distilled water 3g Ferrous Sulfate 8ml Acetic Acid 4ml Grain Alcohol 8g White Sugar Add the iron and sugar to the water and mix until dissolved. Filter this solution twice through cotton or a paper coffee filter. Add the acid and stir. Add the alcohol and stir. (When mixing acids with water, always add the acid to the water; never add the water to the acid.) Store it in a glass or plastic airtight bottle. The iron or ferrous sulfate is the developing agent, the acetic acid acts as a restrainer to keep the developer from acting too fast. The sugar is an organic restrainer and serves two purposes; it allows you to use less of the caustic acetic acid, and it thickens the developer slightly, making it easier to keep it on the plate. These formulae can be modified to accommodate the working environment. In hot weather, you may need more restrainer or less iron to keep the solution from working too quickly and uncontrollably. Hot weather may also induce a chemical fogging during development. This can often be remedied by diluting the developer with water. Fixers: Potassium Cyanide or Sodium Thiosulfate Potassium Cyanide (KCn) is an extremely hazardous chemical, and if handled carelessly, it is deadly. It fixes Ambrotypes and Tintypes more quickly than Sodium Thiosulfate, washes out of the collodion more readily, and sometimes imparts a warmer tone to the plate. KCn is the traditional fixer for Tintypes. Otherwise, it is unnecessary and risky to use. KCn is too strong a fixer for negatives. Potassium Cyanide Fixer, 1.4% solution 14g Potassium Cyanide 1ltr Distilled Water Add the potassium Cyanide to the water and stir until dissolved. Working in a ventilated area and near a sink, far, far away from any children, pets, food, or food preparation areas, set up your scale. Cover the weighing plate with a piece of paper with the sides folded up forming a tray. Place on top of this, a cup for weighing the cyanide. Have a beaker containing the liter of water nearby. Wearing rubber or latex gloves, a dust mask, goggles, and an apron, open the cyanide container, place the cap in a safe place, and spoon the cyanide into the cup, little by little, until you have the correct amount. Pour it immediately into the water, cap the cyanide container, and stir the solution with a glass rod until all the crystals have dissolved. Then, pour the solution into a clearly marked plastic container and cap it. Identify it as Poison! Also label it Potassium Cyanide. Rinse out the measuring cup with water. Take the paper off the weighing plate, fold it carefully in case it collected any misdirected crystals, and place it in the trash. Rinse the mixing container and the glass rod. Carefully wipe down or rinse with water any area in which cyanide crystals may have fallen.