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.

Sodium Thiosulfate (Hypo) Fixer, 20% solution

200g Sodium Thiosulfate (pentahydrate) 1ltr Distilled Water

Add the sodium thiosulfate to the water and stir until dissolved.

Negative Intensification: If you expect to make salted paper or albumen prints, it may be necessary to intensify the negative to gain densety and contrast.

Bleach Solution A:

18 g Copper Sulfate 100ml Distilled Water

Bleach Solution B:

9g Potassium Bromide 100ml Distilled Water

Intensifier:

12g Silver Nitrate 100ml Distilled Water 6drops Nitric Acid

Warning: Nitric acid is extremely hazardous. Handle with caution and in a well ventilated area. Wear gloves and goggles.

Mix solutions A & B together. This will be the bleaching bath. Place the fixed and washed plate into the bleach until it appears white. Wash in running water for a minute, rinse with distilled water. Place the washed plate, quickly and smoothly into the intensifying bath. It will darken quickly. Remove it and wash the plate. Varnish:

420ml Grain Alcohol 60g Gum Sandarac 44ml Oil of Lavender 3ml Distilled Water

Pour the alcohol into a clean bottle. Add the gum, cap the bottle and shake it regularly over the next few days until all the gum has dissolved. Let the twigs, bugs and other impurities settle for a couple of days. Siphon the clear liquid into another bottle, add the lavender oil and water, cap the bottle and shake it.

Glass

Plain clear glass is fine for negatives and positives and can be purchased at frame shops, hardware stores or glass stores. An ambrotype is an underexposed collodion negative that appears positive when a black backing material is placed behind the image. Another option is to expose the image directly on dark opaque glass, thereby eliminating the need for the backing. Black, dark red, or dark purple stained-glass are the most popular choices among ambrotypists. All are referred to as ruby glass, and the resulting Ambrotypes are commonly called Ruby Ambrotypes A glass with a smooth surface will produce the highest quality image. The glass must first be cut to size and the edges dulled with a whetstone. Then it needs to be cleaned and polished. This is done first by running the plates through a dishwasher or by cleaning them with windex and paper towel. Next the glass is cleaned with a homemade solution of whiting.

Glass Cleaner

Add equal parts Whiting (Calcium Carbonate, Chalk), Distilled Water and Grain Alcohol into a squirt bottle and shake. Whiting will not stay in solution, so the bottle must be shaken before each application. Apply a small amount and rub it in vigorously with a paper towel or flannel cloth. As it begins to dry, polish it with a fresh paper towel or a lint-free cotton cloth. Be sure to get all the whiting off the glass including the edges. Clean both sides of the plate then place it in a box to avoid dust. Flowing the Plate

Salted collodion, which is not light sensitive can be poured onto the plate in full light. Choose the cleanest side of the glass and dust it with a brush. Hold the plate from below with your fingertips or grip it by a corner with your thumb and index finger. Pour into the center of the plate with a steady hand and without hesitation. Pour a large enough pool of collodion, so that by tilting the plate ever so slightly you can direct the flow of collodion to one corner, then clockwise to each successive corner. When the collodion has reached the final corner, the excess is poured back into the bottle by resting that corner on the mouth of the bottle and raising the opposite corner while simultaneously rocking the plate from side to side. This final action is to help prevent flow lines or ridges, which may occur during the pouring-off. The collodion will quickly begin to set and should then, in the dark, be set into the silver bath.

Sensitizing the Plate

Working under safelight conditions, the plate is placed on the dipper and inserted, quickly and smoothly, into the silver bath. You may tap the plate on the bottom of the tank and move it from side to side a couple of times. Then, close the lid and let the plate remain in the bath for about three minutes. As you lift the plate out of the bath you will know that it is fully sensitized when the silver solution appears to be flowing freely and smoothly down the plate, without the appearance of drips or unevenness. If so, take it out, rest one corner on a paper towel, blot the back of the plate with a dry paper towel and along the bottom edge to absorb any drips that would otherwise accumulate in your plate holder. Then place it in the plateholder. Depending on the weather conditions, you will have between 5 and 15 minutes to expose the plate.

Exposing the Plate

Since sensitized collodion is only sensitive to the blue end of the color spectrum, there is no effective way of measuring the light for exposure. Your first exposures will be determined by trial and error; your later ones by experience.

Development

Again, working under safelight conditions, remove the plate from the holder and place it in a development tray or hold it in hand for development, if you prefer. While holding the tray or plate at a slight angle, flow a small amount of developer smoothly and continuously along the raised edge of the plate from one end to the other. As the developer flows across the plate, level it off to keep the developer from running off the other side. Then, tilt and rock the plate to keep the solution moving and to be sure that no areas are without developer. Ambrotypes are usually fully developed in 15 to 25 seconds. Highlights will appear quickly, followed by the midtones. Development is halted before the shadow detail appears either by pouring water over the plate or by immersing it into a tray of water. When the water flows cleanly and smoothly over the plate, you will know that development has been stopped and the plate can be taken into the light to be fixed. Negatives are developed more slowly and more fully with a weaker developer solution. Development may take a couple of minutes. With negatives, you will be looking for shadow detail. Negative development may be enhanced by a second application of developer with some silver added directly from the silver bath. Fixing the Image After rinsing the developer off the plate with water, it can be taken into the daylight to be fixed. If you are using hypo, place the plate in a tray of hypo until the image clears. This can take up to 5 minutes.

If you are using potassium cyanide, dip the plate into an upright bath of cyanide which will usually clear the image in 15 seconds. Let it sit for another 15 seconds then move it to the wash.

Wash and Dry Hypo fixed plates should wash in a tray for 30-40 minutes, cyanide fixed plates for 10 minutes. After washing, stand the plates in a plate rack to dry or dry them by hand over the flame of an oil lamp.

Varnishing the Plate Yes, you need to varnish the plate. It will protect the image and keep the silver from tarnishing. You may notice that certain vintage collodion images were not varnished. Occasionally, when a photographer underexposed an image, knowing fully well that collodion images brighten as they dry, he would simply omit the varnishing rather than shoot another plate. This was known as leaving the image “in the bright”. Varnished or not, the finished plate was always encased in glass for protection.

The varnished is flowed much like collodion, but it should be poured onto a warmed plate. After pouring the excess varnish from the plate into a separate varnish bottle, so as not to introduce foreign matter into your pouring bottle, keep the plate at an angle and blot the edges with a paper towel. This will prevent a thick ridge of varnish from forming along the sides of the image. Dry the plate over the flame of the oil lamp.