Large Format Photomicrography part: V

Previously the general program and goals were covered. After which a ground glass focusing screen was cobbled together. A plan for a home built 4×5 photomicrographic camera was outlined, all before finally exposing a sheet of film. This is the point at which enthusiasm begins to come up against the fear of chemistry and nyctophobia that plagues analog photography. Whatever else the writer might be, he is certainly not a chemist, a well-informed photographer, or particularly strict in his adherence to procedure. Fortunately, apart from all that, he is as well not one for whom fear of failure (or failure out-right) has ever been dissuasive!

Now, one could without too much searching locate a mail-order film processor who would happily provide a mailing label and some assurance. Safely packing off ones exposed film (still in holders) to an accomplished film processing service is not for everyone however, and potentially as expensive as processing it ones self. There are a few choices to make, and some purchases that will likely need to be made.


Assortment of powder and liquid photographic chemicals

Here’s what one is going to need:

  1. Developer
  2. Stop bath
  3. Fixer
  4. Developing chamber

That’s all, four things, simple. Developer and fixer can be daunting but it needn’t be, it’s available as kits from all manner of specialty shops on-line, the only hard choice is what to get. First one will need to decide to go with color or black and white. Obviously this is contingent of the film that was used in the earlier posts but one can always choose to color outside the lines and cross process (develop film in alternate chemistry). Black and white processing is simpler so one can’t go wrong with that as a first choice. There’s all manner of options even after one limits the choices to black and white developers but one can generally put them into two very broad categories based on the manner in which they are sold, those that come as dry powders and those which come as a liquid. There are positives and negatives to either but the chief among them is generally perceived to be lifespan.

Developers that are sold as a liquid may be provided as a single concentrated solution or a couple concentrated solutions. Those of both types are added to a prescribed quantity of water to make what is called a working solution that will be the actual developer used. The developers that are sold as a powder have an indefinite shelf life, until they are mixed and the same may be said for most liquid developers. So-called Pyro (PMK or Pyro-Metal-Kodalk) developers generally have a phenomenal shelf life and as a single use developer (working solution discarded after use) may be a good choice for someone who expects to only process a limited number of films in a given year. Regrettably, even as developers (essentially all of which are toxic) go Pyro developers are on the far end of the safe/environmentally friendly spectrum. Pyro developers also impose limits on the stop bath and fixer that one may use in a later step. A concentrated liquid developer such as Ilford’s Ilfosol-3 may be a better choice for anyone who wants to keep their options open.

Powder developers are well worth consideration. One of their modern-day assets, and one which should not be overlooked, is the ease of acquisition. All powder developers are freely shipped to any mailing address through the normal mailing services, they require no special hazard labeling, address requirements, or delivery services (a number of liquid developers are disallowed by the USPS and may not be shipped to PO boxes or residential addresses). The concern that puts many off of using a powder developer is primarily of shelf stability and mixing. Preparation of the developer from powder is far simpler than one may expect. As most home plumbing can supply water at the recommended mixing temperature an inexpensive pitcher, spoon, and thermometer are all that is required, then follow the directions on the packet. Self stability of the mixed solution may be easily addressed by keeping the mixed developer in full, small, brown plastic bottles-the sort in which hydrogen peroxide is sold are excellent. Most powder developers mix to create a US gallon of concentrate and will fit exactly in four, empty, one quart, hydrogen peroxide bottles.

The stop bath is more restrictive for color film processing and one may employ a plain water stop for most black and white processing. There’s no need to buy a specialty stop bath although of course, it is an option some photographers will never give up.

Fixers are a necessity however, and much like developers are available as both powders and concentrated liquids. Shelf life is generally not an issue with fixers and unlike developers are frequently used for multiple rounds of use before they are discarded. The two primary varieties of fixer are those which are acid and those which are called archival (base). In a general way one can always achieve acceptable results by making use of the flagship fixer made by the same company that produces the developer. Alternatively one is free to make use of the classic standby, sodium thiosulfate, popularly called plain hypo or photographers hypo. Hypo has the particular benefit of being widely and inexpensively available in brick-and-morter pool and hot-tub supply stores where it is sold as a chlorine reducer.

One may as well employ a dedicated final wash but much like the stop bath it is a matter of personal choice. To many it’s an unnecessary complication that is best when in the form of plain tap water.

This is already too long so next time, developing containers! -K


One thought on “Large Format Photomicrography part: V

  1. Pingback: Large Format Photomicrography part: VII | vade mecum microscope

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