The following vocab words and concepts will get you started working and understanding the recipes and literature.  Reading from the Light Farm literature list will rapidly pad your comfort zone.  There is a key concept here that is crucial: learning is a positive feedback loop.  You will not know how to make emulsions until you start making emulsions.  With each lap around the circle you will understand a couple more ideas and procedures.  The great gobs of words written by Baker, for example, will actually start, first, to make sense, and then to sound like poetry, as the cadence of slightly archaic style weaves through your experience. 

Dry plate (or gelatin dry plate):   Silver gelatin negative emulsion coated on glass, dried before storage and exposure.  Same as "glass negative".  (As opposed to 'wet plate', which is not a gelatin-based process).

Gaslight paper: Any of a variety of very slow papers, usually AgCl.  The name comes from the fact that the paper didn't require a darkroom.  It could be worked in the light of a low-burning gaslight. Today, that implies a bright amber safelight, although any paper should be tested for light sensitivity.  Because of their speed, gaslight papers are by definition contact printing papers.

Emulsion: Photographically, a silver halide solution, dispersed and suspended in a viscous material (colloid ) - gelatin in our case - along with any number of other specialized additions.

Silver Halides: Light sensitive compounds of silver formed during emulsion making: silver chloride (AgCl), silver bromide (AgBr) and silver iodide (AgI), often designated generically as AgX.  There are any number of chemicals that can contribute the Cl, Br, or I parts of a silver halide.  The 'Ag' part is always from silver nitrate (AgNO₃).

Bloom: verb: In a recipe, means to swell gelatin in water.

Bloom: noun: "Bloom number", a measure of the hardness of the gelatin.  We generally use 250 bloom (hard/photographic gelatin).

Frilling: On glass negatives, the emulsion lifting or floating away, usually from the edges of the plate.

Acidic: pH below 7.0

Alkaline: pH above 7.0

Albumen: Egg white

Baryta: Shorthand for baryta-coated paper, today usually glossy.  Gives the smoothest surface for coating.

"Subbed" (film): From 'substrate'; film base that has been coated with material that helps the emulsion adhere through the various processing steps.

Halation and Antihalation layer: During exposure of film or glass plates, light passes through the emulsion and bounces off the substrate and back again through the emulsion.  This can cause halos to form around objects => halation.  Modern films have a layer that prevents the light bounce-back and eliminates halation => antihalation.

Surfactant: Wetting agent. I use Photoflo 600 and Everclear for almost all my work.

Everclear: High proof ethanol alcohol and for all intents and purposes indispensable for emulsion work.  Although Everclear is a brand name, it is also the generic reference to similar alcohols.  In Oregon the brand is Clear Spring.  Everclear is illegal in a number of states, but worth the drive to find.  Buy it by the half gallon.

Emulsification and Ripening are the two parts of the first stage of emulsion making.  Shredding (if needed), Digestion and adding Finals are all part of the second half right before coating.   If time constraints require, the washed noodles can be lightproof refrigerated for a number of days before coating.  This breaks the entire emulsion making process into three manageable steps.  It is possible to go from raw materials to finished prints in one week of a couple of hours of work a day.

Emulsification (also called Precipitation): The first and main reaction of silver halide formation (the addition of silver nitrate to at least one salt).  This step determines in large part the characteristics of the final emulsion. 

Ripening (also called Physical Ripening or First Ripening): This step determines whether the emulsion will be a fine-grained slow emulsion or a larger grained faster one.  You will sometimes see the entire step referred to as Ostwald ripening, although this is technically a subset process of ripening.

Shredding (also called Noodling): In washed emulsions, breaking the ripened, chilled emulsion into little pieces ('noodles', 'shreds', or 'worms') to facilitate washing out ammonia (if used) and excess salts that could re-crystallize on film or a plate.

Digestion (also called Chemical Ripening, Second Ripening, or After-ripening): At this point various additives are inserted primarily for influencing sensitivity and gradation.  (For instance, additives are necessary to make a film panchromatic, i.e. sensitive to the full visible spectrum. Silver halides are naturally sensitive to only blue-violet light.)

Finals: The final addition of stabilizers, hardeners, surfactants, and/or preservatives.  The list of things possible to add to emulsion is impressive:

A Personal Opinion: An emulsion can be a very simple thing or a mind-bogglingly complex thing.  Not surprisingly, as the technology marched through its history, it became increasingly complex.  The modern products are as close to a miracle as I require.  It would take a small library and a degree in photographic chemistry to understand everything, even if most of the information weren't secreted away in locked vaults.  All that elusive information is seductive, but not a necessary or perhaps even desirable starting place.

The ins and outs and ups and downs of each and every addition possible are  worthy lines of exploration, but it is my belief that we are better off starting simple (as did Abney and Eder) and learning the complexities a step at a time - in effect retracing the forward movement of the history of emulsion making.  This is not only more feasible, but also more likely to succeed, than starting from  state-of-the-art emulsion manufacturing technology and from there trying to backward engineer a just-simple-enough product.