Dry Plate Workshop v2
by Terry Holsinger


Just so everyone is on the right page, this workshop will be about making “Dry Plates”, which includes learning how to

  • cut the glass,
  • clean the glass plate,
  • make a silver gelatin emulsion
  • coat the glass plate,
  • determine the effective “plate speed” that will allow you to make glass negatives.

All the methods discussed will be mine, personally, and are not necessarily the only way to do them. Other options are sometimes mentioned as a note or in the Appendix, as are discussions and outcomes from the winter ’06 workshop sessions. It will be a bit of what I call “kitchen table chemistry”. Since the making of a dry plate will require a number of different skills, it does not, in my opinion, lend itself to a simple single-day workshop, so this two-day workshop was designed.

You might want to practice coating plates the size you will use before attending the workshop or mixing emulsion. You can do this until you get good, even coverage to the edges of the plate. Just mix some store brand gelatin and water to the same ratio as your emulsion (1:24 or 1 ounce gelatin to 500 mL water) and add a drop or two of food coloring (not red), so you can see it on the plate. Mix your gelatin with cold water, let it sit for a couple of minutes, and warm until the gelatin melts. Then, practice coating until you are able to repeatedly obtain an even coat while working under a safe light. You can easily clean the gelatin off the plates using a little hot water with some bleach added.

You do not need to have a view camera to participate in this workshop. There will be cameras for use or

  • You can make and use a pinhole camera.
  • You can use the dry plate to make an enlarged negative or a positive “lantern slide”.
  • If you have a view camera, and a plate holder, not film holder, you can go to the glass store and have them cut you some glass (single strength or thinner) to fit.
  • You can also modify
    • an old box camera, or roll film camera to take a single plate.
    • a film holder with a metal septum to hold a single plate.
  • Inexpensive picture frames have thinner glass that will fit in a regular film holder.

If you are going to use the plate for an enlarged negative or lanternslide, all you need to do is to have the store cut single strength glass to the size you want to enlarge to.

Like most of the historic (alt) processes, making glass plates has many process steps, during any of which things can go wrong. If you want consistency between plates, you need to maintain a higher-than-normal level of “process control” and lab cleanliness. This is not beyond what you can do. But fear not. If you have a relaxed sense of process control, or work on the “kitchen” table, you can still make plates. You are just more likely to have a greater variance between emulsion batches.

Contrary to what the “Zonies and Techies” will have you think, photography is not an exact science. There are so many variables that go into each attempted photo, from inspiration to finished image that one should roll with the punches and not always try to control things too much. The batch-to-batch variations that you get with making your own emulsions can be minimized, if you are willing to work in laboratory conditions and use stringent process control. If, like me, you are not willing or able to do this, you can still make great images with your own emulsions and have fun doing it.


Some folks might wonder about the level of hazardous chemicals that we use to make dry plates. Compared to many of the other historic processes (and wet plates, especially), most of the chemicals we use are rather benign. The most dangerous chemicals are the silver nitrate and the ammonia, if it’s used. You must keep the silver nitrate out of your eyes and do not breath the dust, as it readily attacks your mucus membranes and can cause blindness. It also will permanently stain your skin and clothing, where contact is made.

The Ammonia Type solution was tried with household ammonia in the first session and found to be ineffective. Therefore, it requires industrial strength ammonia, which requires care that you not inhale it while handling. Skin contact could also be a problem, especially if you are already sensitive to it. Keep it out of your eyes and do not drink it. I have not tested this process using industrial strength ammonia. Refer to Appendix – Emulsion Recipe Options.

MSDS for the chemicals will be available for anyone who wants to review them. Refer to Appendix – Safety for more information.

Cutting the Glass

Measure twice. Cut once. Measure the holder you will be using because they all seem to vary. There is more than one “standard” size for half-plate (and other size) negatives. Make sure your glass fits your holder.


  • Flat surface for cutting
  • Newspaper to collect the splinters & shavings
  • Glass (Ruby or dark glass does not work for this process.)
  • Straight-edge
  • Marker (dark fine-point Sharpie works best)
  • Glass cutter (The type that holds oil in the handle is easiest to use.)
  • Glass pliers (optional – for the less experienced glass cutter)
  • Ceramic knife-sharpening stick or a glass-sanding block or stick

Once you have the glass cut to the correct size, take a ceramic knife-sharpening stick or a glass-sanding block or stick and run it along the edges of the glass to knock off the sharp edges. (I also knock the sharp edges off the corners.) You need to be very careful at this stage or you WILL cut your hands later while working with the plate.

Cleaning the Glass Plate

This method works best if you have running water to wash your plates and a separate, clean place to allow them to dry.


  • Powdered cleanser
  • Running water
  • Distilled water
  • Drying rack (IKEA has one for $5. I use the dish washer’s plate rack, as it minimizes the dust by closing the door.)

Place the glass plates under running tap water to wet them, then sprinkle on the dry cleanser and rub/scrub the plate, both sides, with your bare hands. By doing this you are also cleaning the oils off your hands. After a good “scrub up,” rinse the plate front and back under the running water and place on its edge in a rack. After the plates are clean, rinse them off with a little distilled water, then dry them, either with a lint free CLEAN cloth, or put them back into the rack to air dry. Note: Refer to Appendix – Cleaning 1. b. i. and POST DRY PLATE WORKSHOP DISCUSSION Second Session, Bullet 2-2, for discussion on this topic.

Refer to Appendix – Cleaning, for a dry cleaning method and information on how to remove emulsion from plates for re-use.

If you are using Mylar, acetate, plastic, metal, or some other substrate, you will need to find an appropriate cleaner. The plastic-type substrates tend to scratch easily. Also note that many of them are dimensionally less stable and have a shorter lifespan, unless dropped, than glass.

Making a Silver Gelatin Emulsion

This section includes information from other sources, including unblinkingeye.com, and personal and workshop experience.

This is the part of the process where you can spend a lot of time trying to get the desired results. For your first emulsion, something that is light sensitive with low fog should be the only result desired. Though this is not too hard, there are no guarantees. Making emulsions is a science, BUT there is also a little voodoo involved. Very small changes in your process or materials can make a big change in how the emulsion behaves. Emulsions have more in common with baking than most of the other historic processes. Any change in the process can make a noticeable difference in the goods.

Stated simply, the process adds silver nitrate to a mixture of gelatin and a halide. The first step in making emulsion is to heat a mixture of gelatin and your halide of choice in the mixing kettle. Then add the silver nitrate (mixed in distilled water) to the halide mixture at a rate to get your emulsion close to the speed/contrast desired. The speed at which you add the silver to the halide will set the base speed of your emulsion. Adding the silver quickly gives you a slower emulsion; adding it slowly gives you a faster emulsion. The slower the emulsion, the higher the Max-density range.

You will then ripen this mixture at the correct temperature to grow the silver halide grains, which increases the speed of the emulsion. Next, you will wash the emulsion to remove the remaining reaction products. Then you will reheat the emulsion, during which time you can add “extras” (contrast agent, dye sensitizer) to further modify the emulsion to your requirements. Finally, you will coat the plate, allow it to cool until the gelatin sets, then dry the plate for use.

Every batch of gelatin will be different. Some make a faster emulsion, others a slower emulsion. The amount of time you take to add the silver nitrate [Refer to Appendix - Emulsion] will affect the speed and contrast of the emulsion, as will the temperature at which you mix it. The choice of halide will greatly affect the spectral sensitivity of the emulsion as well as the speed. The amount of time and temperature the emulsion spends ripening will affect the speed and fog level of the emulsion. The efficiency of the washing stage will also have an effect, as will any additives introduced after the washing stage or the after-ripening stage.  As you can see, there are many things that will affect the end result.

There are two main ways to mix your emulsions, either in “large” batches, where you coat a number of plates with the same batch; or, if your process control is good, you can make small batches and only coat a couple of plates at time. I normally make a batch large enough to coat 10-20 plates. This allows me to test a few plates to determine the speed and then have a number of plates available to shoot at that speed. If you use the same batch of gelatin, same batch of chemicals, same batch of distilled water, and the same process to make your emulsion you should have a good starting point for your different batches. Do not expect them to be as consistent as modern manufactured film, though they might be as consistent as the manufactured liquid emulsions.


  • Gelatin (either unflavored gelatin - Knox or store brand - from the grocery or a gelatin from your favorite photo chemical supplier; I have used both) Note: Gelatin is the unknown variable in the chemistry because it is a large organic colloid molecule and an amphoteric protein. (It can react chemically as either an acid or a base.) Gelatin sources and processing methods vary, impacting your final result. In photography, ossein (demineralized bone) gelatin is preferred and commands a premium price. See http://www.gelatin.co.za/gltn1.html for details.
  • Silver nitrate,
  • Halide (xx chloride and/or xx bromide and/or xx iodide) xx chloride, and/or xx bromide and/or xx iodide *
    Distilled water
  • Thermometer good up to 100ºC/212ºF
  • Measuring devices (non-reactive, accurate and capable of consistent repeatability with small amounts of dry or liquid and large amounts of water)
  • Mixing kettle/pot (non-reactive glass, stainless, high temp plastic, etc.)
  • Large container to heat water bath for mixing container (above)
  • Newspaper or something to catch the drips while coating and transporting to gelling box.
  • Stirring device (non-reactive – A mechanical stirrer would be useful, but not essential.)
    Heat source (Wal-Mart sells 1-burner for $8; 2-burner for $20)
  • Gelling “box” (ice chest, freezer, refrigerator without a light, etc.)
  • Drying “box” (light tight and big enough for your plates; ideally with air circulation)
  • Wax paper to prevent sticking when drying or stacking dry plates
    Coating device (non-reactive dropper, spoon, rod, etc.)
  • Darkroom with red safelight to mix and coat in (Red LED at 600nm is ideal. Headlamps sold at Academy & Wal-Mart for about $15. Home Depot & Lightbulb Store sell replacement bulbs. Kodak 1A filter, or equivalent works.)
  • Standard B&W processing chemistry and trays for processing exposed plates
  • Optional: Chrome alum (from your photo chemical supplier) for hardening the emulsion
  • Optional: Alcohol (ethanol aka Everclear, or denatured) for washing/leaching
  • * The xx in the halide section is there to allow for your choice of halide, i.e. sodium chloride, potassium chloride, ammonium chloride, etc. You can even use table salt (sodium chloride), or if you have potassium bromide in the darkroom, it will work as well. H.J. Wall, in his book How Photography Works, explains halides.

      “The majority of silver compounds are photosensitive, but for nearly all photographic purposes three suffice; silver chloride (AgCl), which is used for slow (contact) printing papers; silver bromide (AgBr), which is used in negative emulsions and in fast enlarging papers; and silver iodide (AgI), small quantities of which are used along with the bromide in fast negative emulsions.

      “As the elements chlorine, bromine and iodine belong to the group known collectively as the halogens, the three compounds are sometimes called generically silver halides. However, the bromide is photographically much the most important silver halide, and by far the most experimental work has been done with it. Therefore, a reference to silver bromide is often taken to mean “silver bromide or other halide or mixture of halides.”


Silver chloride emulsions are sensitive to UV and “light” blue ~350-430nm,
Silver bromide emulsions are sensitive to UV and blue-green, ~380-460nm,
Silver iodobromide emulsions are sensitive to UV, blue, and green ~380-520nm


Now that we’ve had an overview of the process, let’s get down to bid’ness. The base recipe for the neutral type emulsion used for this workshop is listed below. It is known as an iodobromide film emulsion from James & Higgins’ Theory of Photographic Process, 4th edition. By changing only the halide in this base emulsion, you can also make a bromide emulsion, a chlorobromide emulsion, or a chloride emulsion. The big difference between these emulsions is in their spectral response. Each is sensitive to slightly different wavelengths of light. (See Notes above.)

I prefer to use the word recipe, not formula, since emulsion making is much like baking. There are a lot of different recipes out there for pizza crust and they all give different results. EVEN when made from the same recipe, by the same person, in the same way, they are often different.

Neutral Type Emulsion

Refer to Appendix – Emulsion, Recipe Options, Calculator, for a spreadsheet that will calculate these ingredients based on the amount of silver you want to use.

Bromide Solution

absolute ratio

for 28g silver nitrate

for 14g silver nitrate**

KBr (g)                                      165




KI (g)                                         5




Gelatin (g)*                                 65




H2O (ml)                                     1700




* To make an emulsion with a finer grain split the first gelatin amount between the halide/bromide and the silver solutions before mixing. Works with all emulsions recipes.

Silver Solution




AgNO3 (g)                                 200




H2O (ml)                                   2000




Extra Gelatin - dry




           (g)                                  250




Extra Gelatin & H2O




Gelatin (g)                                  100




H2O to make 6.3kg (6300ml)    


.882kg (882ml)

.441kg (441ml)

** This is what we used for the workshop. We managed to coat about 1200 square inches of glass with the 441mL of emulsion we mixed. (That’s 60-4x5 plates). 882mL would coat ~120 4x5's

Before you begin, weigh the different chemicals and keep them handy. Make sure the water bath is at the correct starting temperature of 70ºC.


1. Mix up the halide/bromide solution. Make sure it is at the same temperature as the water bath.

2. Turn out the lights. Now the fun starts! Under safelight, mix the silver solution by adding the silver nitrate to all the water at 70°C, making sure it has completely dissolved.

3. Combine the silver and halide/bromide solutions (precipitation). With both solutions and the water bath at the 70°C temperature, add the silver solution to the halide/bromide solution at the correct rate for the speed you want. (Refer to Appendix – Emulsions – Speed Chart. The speed at which you add the silver to the halide will set the base speed of your emulsion. Adding the silver quickly gives you a slower emulsion; adding it slowly gives you a faster emulsion. The slower the emulsion, the higher the Max-density range.) Keep mixing the solution well during this time. (Vigorously is the word often used, but thorough and steady is best.)

4. Ripen the mixture. After all the silver solution has been added, keep stirring the solution, slowly and steadily, and keep both the solution and water bath at the same temperature for 20 minutes. At this point, heat is enlarging the silver crystals to help increase the speed of the emulsion. After the 20 minutes have passed, and while stirring, cool the emulsion to 45ºC.

5. Add the Extra gelatin - dry. Add it slowly while stirring steadily.

6. Wash. Stir for another 20 minutes, then remove the emulsion form the water bath and wash it, using one of the following methods. (If proceeding to the Session 1 Process, you can chill the mixture overnight, in a DARK place, at this point. Reheat to 45ºC and proceed.) The washing step removes the bromides and nitrates, which would prevent the developer from working.

  1. Session 1 Process (leaching): To do this, measure the amount of emulsion you have. Now, start adding the ethanol, until the gelatin separates from the water. Remove (decant) the water/ethanol mixture. Rinse the remaining gelatin emulsion in cold (0-5º C) distilled water. Using cold water will cause the coagulated emulsion to swell less. (Many small washes are better than one large one.) Then add enough distilled water so that you have the same amount of emulsion as you did before you started the wash cycle. Heat this in the water bath to 42C until the emulsion has re-melted. Note: The emulsion in this session was very thin & did not produce density in the images. It could be that the ph was not correct or that not enough ethanol was used. Alcohol could also be used. You are looking for something more hydroscopic than gelatin.
  2. Session 2 Process (chilling, noodling & leaching): Chill a gallon of distilled water and the emulsion until it is thoroughly gelled (2-4 hours.) Place the emulsion in the center of a large square of cheesecloth and gather up the corners. Holding this over a non-reactive container of cold water, twist the loose ends of the cloth, forcing the gelled emulsion through the cheesecloth and forming noodle-like strands. (This group did not have cheesecloth, so cut the emulsion into ¼” - ½” cubes.) This exposes more surface of the emulsion to leech out all the halides. Gently pour cold distilled water over the noodles to twice the amount you started with. Wait 2-3 minutes, then pour off most of the water. Add cold distilled water and pour off, as before. Repeat four more times (six times total.) Note: The emulsion in this session was thicker & produced images with moderate density. Alcohol or ethanol could also be used for the first one or two washings. You are looking for something more hydroscopic than gelatin.
  3. Note: The ethanol solution flocculates (gathers or coagulates loosely; precipitate from solution in the form of fleecy masses) the bromides and nitrates; decanting physically removes them. A centrifuge might also work to remove them from the solution. Safety Note: Most everyone in the first Session got “high” from the gaseous exposure to ethanol, which was heated in solution, going into the blood stream at a faster rate. A good ventilation system or wearing personal protection equipment (e.g. a 1/2 mask respirator) would help tremendously.

7. Add the Extra gelatin & H2O (emulsification) and “after-ripen.” Heat the emulsion slowly. Do this at no more than 60ºC for no more than 30 minutes. During this time, you can test. (Refer to the next step.) Adding a very small amount of a very weak hypo solution greatly increases the emulsion’s speed. Cool the emulsion slowly, to 40ºC. Caution! This step can build fog in your emulsion if the temp is too high and/or the time is too long. So it’s best to keep this stage short and on the cool side. The after-ripening does not noticeably increase grain size, but it does increase speed.

8. Test. It is best to do this during the after-ripen (previous step). Spread a thin layer of the emulsion on a piece of paper strong enough to withstand development. Allow to dry. Cut the paper in half. Expose one half; develop both halves. The exposed half should be black, showing that the emulsion is sensitive. The unexposed half shows you the fog base.

To work for more speed in your emulsion, you will need to control your exposure and do multiple tests. Continue to after-ripen (previous step) until you first notice fog develop. Immediately stop the after-ripen and coat your plates.

Another way to test only for fog is to put a drop of emulsion, every few minutes, into a clear beaker with strong developer in it. When it turns light gray, the fog level is adequate.

Note: Due to time constraints, workshop participants began coating while the test sheet was drying. No “extras” were added to the emulsion.

9. Coating the plates. Immediately before coating your plates, you can add hardener to the emulsion, if desired. To coat a 3½ by 4½ inch glass plate, you will use approximately 4 mL of emulsion. Hold the glass plate level, pour on the solution, and spread it uniformly.

  • Technique – Distribute the emulsion as evenly as possible, removing all bubbles.
  • Applicators used were
    • an eyedropper (difficult for larger plates; dropper can be used to transfer emulsion to the plate or remove bubbles from it);
      a plastic spoon (worked well);
    • a glass coating rod/puddle pusher (easy to use and even coating resulted if solution was thick enough, though the rod had to be cleaned often, as it “gummed-up” with each pass); or
    • a coating knife (not used but recommended by Terry.)
    • You can also pour and tilt the plate (much like you do with wet plate) however the gelatin thickens as it cools on the plate.
    • Floating is possible, but more prone to failure. Floating a stiff material, like glass, often creates air bubbles. Floating a flexible material will usually yield an even coat, but cause the material to curl, unless it is coated on the back.

10. Chill & Dry. Place the coated glass on a level cold surface in the dark, until the emulsion sets (approx. 10 min). You can also use an inverted bowl in the freezer (without a light) or the top of a contained ice block in a cooler. Then place in the dark to dry (hours).

11. Expose. Make your first test exposure, shooting a scene with bright white and shadow areas for range, at 1/30 second at f/8, and adjust up or down as necessary. If possible, expose ½ or 1/3 of your plate at a time, giving you multiples of the exposure on one test plate. ASA – Session 1 = 5 (nearly about); Session 2 = 2  NOTE: The iodobromide emulsion is sensitive to blue, the same as wet plate negatives, so medium to light blues will wash out.

12. Develop. Develop in an active developer such as Kodak D-8 (2:1), HC-110 (Dilution A), or Dektol (1:1). See Appendix – Develop, to see some negatives.


  • Develop – Times varied greatly from 4-12 minutes for the Fall ’06 workshops. Develop by inspection. (Keep that red LED handy.) Generally, a printable image should emerge after the first minute. Longer development builds up shadow details in the dark and white areas
  • Stop – Times varied from 2-30 seconds. A water stop was used, so needed to be changed frequently.
  • Fix – Times varied from 4-15 minutes. Fix by inspection. (Look at the back side of the plate. When all the white is gone, your emulsion is fixed.) Note: You can over-fix and lose your image.
  • Rinse – 5 minutes is sufficient, since only the emulsion will have absorbed any chemicals.


Chemical suppliers per web as of June 2006


James, T.H. & Higgins, George C; Fundamentals of Photographic Theory. 1968: Hastings-on-Hudson: Morgan & Morgan, Inc.

Wall, E.J: Photographic Emulsions. 1929: New York: Oxford University Press (Oxford series in optical and imaging sciences, vol 8.) London: Chapman & Hall – their preparation & coating on glass, celluloid & paper, experimentally on the large scale.


Most chemical supply companies and many universities with chemistry programs have free Material Safety Data Sheet (MSDS) search engines. Two places to look include:

Mr. Yuk Stickers

An excellent tool for teaching children about poisons. Every “Poison Help!” Mr. Yuk sticker includes the nationwide toll-free number (1-800-222-1222) that connects callers to the nearest Poison Information Center. Poison information services are available through this number 24 hours, seven days a week.

For a free sheet of Mr. Yuk stickers, send a self-addressed,
stamped business-size (#10) envelope to:

Free Mr. Yuk Stickers
Pittsburgh Poison Center
3705 Fifth Ave.
Pittsburgh, PA 15213


Clean the glass

1. Dry method of cleaning glass. Scully & Osterman used this method at their wet plate workshop. You can use a product called Glasswax or a supersaturated mixture of calcium carbonate in water. Mix it in a small-mouthed container, such as a dish soap bottle with a flip-top cap. You need to shake well before each application because the particles settle quickly. The cleaning process can be done without additional water, besides what is mixed in with the calcium carbonate. (Terry H does not endorse this process, since it was not tried when making dry plates.)

    a. Supplies

       i. Cut glass
       ii. Cleaner – calcium carbonate mixture or Glasswax
       iii. Many clean, soft, lint-free rags
       iv. Glass vice (optional)
       v. Rack (can be used later for drying exposed plates)
       vi. Staging areas – 3, plus the rack

    b. Process

       i. Stage 1 – With glass laying on a rag, apply a small amount of cleaner to the glass. Using another rag, spread it around applying substantial pressure. This is to remove any residue from the glass and to give it a “tooth” to hold the emulsion. Additional cleaner may be applied, if necessary. It is not necessary to remove all of it at this stage. Flip the glass and repeat on the other side. Pick up the glass by the edges only and move to the next stage.

       ii. Stage 2 – With the glass laying on a rag, use another rag to remove remaining cleaner from the glass and begin polishing it with strong circular motions. Flip the glass and repeat on the other side. Pick up the glass by the edges only and move to the next stage.

       iii. Stage 3 – With the glass laying in a glass vice or on a lint-free rag, use another lint-free rag to continue polishing the glass. Do this until to you can breathe onto the glass and no marks, streaks, or unevenness appear in the condensation. Using the cloth to hold the edges of the glass, move it to the rack. If you have determined that one side of the glass is better than the other, face that side to the left in the rack.

2. Cleaning glass with bad emulsion/negative on it. – You can easily clean the emulsion or practice-gelatin off the plates using a little hot water with some bleach added.


Click here for the Emulsion Calculator (.xls file).

Speed Chart

Time of

Average Grains per Milliliter

Average Area

Average Thickness (μ)



0΄ 31΄΄

6.85 x 1011






2.09 x 1011






0.63 x 1011






0.28 x 1011






0.17 x 1011






0.09 x 1011






0.04 x 1011





Chart found on page 28 of James’ & Higgins’ Fundamentals of Photographic Theory.

Recipe Options

Bromide solution

absolute ratio

for 28g silver nitrate

KBr (g)                      200



KI (g)                         5



Gelatin (g)                  125



H2O (ml)                   1750



Silver solution



AgNO3 (g)                250



H2O (ml)                   175



Ammonia: Drops, only as needed

Extra Gelatin



Gelatin (g)                  250



H2O (ml)                   1250



First, weigh the different chemicals and keep them handy. Make sure the water bath is at the correct starting temp, 50ºC. Then, mix up the halide solution and make sure it is also at the same temp as the water bath, 50ºC. Now the fun starts. Under safelight, take half the water, at 50ºC, for the silver solution and add the silver nitrate to it, making sure it completely dissolves. Now, using a very controllable device (eyedropper for example), start adding ammonia to this solution. With the first drop of ammonia, the clear silver solution will become cloudy/opaque. Continue to add ammonia, drop by drop, until the solution becomes clear again. Measure the solution’s volume and add water to make up the remainder of the amount needed. To use this method you need ammonia that is much stronger than what you can find at most stores. In other words, you need industrial grade ammonia. Because of this, we will not make this type of emulsion in the workshop.

With both solutions and the water bath at the same temperature, add the silver solution to the halide/gelatin solution at the “correct” rate for the speed you are trying for. (Refer to Appendix – Emulsions – Speed Chart.) Keep mixing the solution well (vigorously is the phrase often used), during this time. After all the silver has been added, keep stirring the solution and keep both the solution and water bath at the same temperature for 30 minutes. At this point, you are enlarging the silver crystals to help increase the speed of the emulsion. After the 30 minutes have passed, and while stirring, add the “second” gelatin solution, which is also at the same temp.

After another 15 minutes, remove the emulsion from the water bath and wash it. To do this, measure the amount of emulsion you have. Now, start adding the ethanol, until all the gelatin separates from the water. Remove (decant) the water/ethanol mixture. Rinse the remaining gelatin emulsion in cold (0-5ºC) distilled water. (Many small washes are better than one large one.) Then add enough cold distilled water so that you have the same amount of emulsion as you did before you started the wash cycle. Heat this in the water bath (~40ºC) until the emulsion has re-melted and you can either add your “extras” at this point or start to coat your plates.

Unblinking Eye

For process instructions go to http://unblinkingeye.com/Articles/Emulsion/emulsion.html.

Bromide solution

absolute ratio

for 28g silver nitrate

KBr (g)                      32



KI (g)                         0.8



Gelatin (g)                  10



H2O (ml)                   360



Silver solution



AgNO3 (g)                40



H2O (ml)                   400



Extra Gelatin



Gelatin (g)                  40



Storing – Unused emulsion can be stored frozen in a light-tight, airtight container, for at least 6 months, though the speed might increase and the fog level could change.



Post Dry Plate Workshop Discussion

First Session did the alcohol/ethanol wash: lost much emulsion and it was very watery.
Stephanie's later attempts to apply a second coat didn't result in better plates, however rod coatings were easy & even. Hardening between emulsion applications might have helped.
Thicker coatings worked best.

Second Session did "noodle" clearing.

  • Negatives in this session were flat.
  • Many in the group had a problem with their emulsion coatings lifting during processing of the exposed plates.
    • One suggestion was that lifting occurred along cracked edges (outside edges that were "chipped" also fall into this category). However, Terri purposefully coated a scalloped edge inside of her plates & did not have this problem.
    • Another suggestion was that the glass cleaning was inadequate, as lifting did not occur consistently in group 2 plates. It did seem to be consistent for each person.
    • Another suggestion was that the thinner picture-frame glass Terry bought was more likely to lift, reason unknown. (We would need to have a bigger sampling to determine the cause.)

Discussion of whether you can develop these in pyro (You can under a green inspection or normal safe light, per usual.)

Some of the images had a dull "pink tint" as if they had been toned. Re-fixing helped reduce the redox (reduction-oxidation) process in one of Stephanie's plates. Be aware that you can over-fix and loose your image, too. The color could also be a reaction to the chemistry used or the thickness of the emulsion layer.

DARKROOM - The space used for the Session 2 was excellent. It is located on East 3rd St at Chicon and managed by Scott (512-542-9261). We rented it for a fee per attendee. Usually it is rented for a monthly usage fee. Scott was very helpful to make the space as usable for our workshop as possible. It’s also within walking distance of Azul on 1st St at Chicon, and Café Mundi on 5th St between Chicon & Comal. Otherwise, it is a darkroom & gallery/studio space with multiple B&W and color enlargers, a large UV exposure box, a large L-shaped wet processing sink, and a 16x20 screen print dryer that holds at least 8 prints. (I’m sure there are other amenities that I’m missing here.)


General Questions for the Workshop Participants:

1. I was thinking of restructuring the document to be more of a process to follow, with comments for each process step about what was done & the results for each session. What do think about this?

  • Good idea to restructure this good pertinent information
  • Good idea
  • That's a great idea!
  • Good idea to restructure and tighten up the English, especially if it is going on-line on the AAPG website.  Excellent information important to record

2. Do you think information in this document that wasn't actually used should be moved to the Appendix?

  • Not if it was alternative process information. Extra asides of interesting or relevant to topic information should be isolated to the end of the document.
  • Yes
  • Yes
  • OK with me.

3. Do you have any other comments you want to make about the document?

  • No
  • Didn’t know whether we were correcting the English, the organizational flow, the procedures, etc.  Disregard any comments or corrections that do not fit the criteria.  I kept getting confused as I went along.
  • I'll put them in the document. I have more at home, too, that I'll add later.
  • None, except what I sent in the document

4. Do you have any comments you want to make about the workshop - organization, space, time allowed, cost, other stuff?

  • I generally liked the DARKROOM space. Tables for glass cutting would have helped, as well as a place to dry the plates so they wouldn’t be splashed from others being washed. Drying coated plates is probably the most difficult thing to arrange, especially for any number of people.
  • I thought the DARKROOM space was great. The only things that could have made it better would have been sturdy tables for cutting & polishing glass & a better way to dry to the plates. It was great to have use of the print dryer. It just made the emulsion prep space very warm.
  • Cost reasonable. Time manageable. DARKROOM space had many nooks that different people could simultaneously do different steps of the process in. The crux is always figuring out the overnight drying without exposing.
  • The workshop was excellent. Terry did an outstanding job as instructor and guide. His caring guidance was much appreciated. However next time we should have some really flat table top to cut glass or have each person go to the glass shop.


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