The pyrogallol is one of the oldest development agents used in photography, a young old man. Although his first experiments began as early as 1802, he will gain much more popularity with the advent of calotype. Mainly as a development for paper negatives.
Gallic acid was however a weak and slow development. A way was therefore sought to make it more effective.
Gallic acid was modified by heating. This process changed the chicken into a pyrogallol. The term pyro comes from the Greek πυρο which means fire.
The pyrogallol was one of the most used detectors in the nineteenth century. Certainly one of the best, regardless of the difficulties of use. Oxidation, desensitization of the emulsion and tanning characteristics. Due to these characteristics, the Metol / hydroquinone formulations took over.
Many photographers solved the problem by formulating detectors that nullified its defects. The problems arose above all on negatives to be enlarged. The prints were certainly sharp, but the grain was very pronounced. In some cases it was pleasant in others less so.
After the end of the Second World War, and the greater use of 35mm machines, the pyrogallol almost risked disappearing for this reason. Only a small group of photographers continued to use it.
Today the pyrogallolo has found a place in the photographic world. Even in the advent of digital, its use in various formulations has increased. Still today new detectors are created with this old agent.
In this small article, I will give some indications on the various formulations, but I will mainly examine the legendary ABC pyro, and its variants. And the PMK that I find very interesting.
Pyrogallol, (1,2,3-trihydroxybenzene) comes in the form of a white crystalline powder. It is a phenol whose chemical formula is: C6H3 (OH) 3 = 126. It has hardening properties on gelatin, and develops an additional colored, yellow image.
This helps to increase the density of the negative. The colored image develops in solutions without, or with irrelevant doses of sodium sulphite. High doses of this agent improve maintenance, thereby hindering the formation of the additional image.
The maximum of its energy, the pyrogallol, expresses it with caustic alkalis. Although it works well with carbonates. The solution is not preserved in alkaline solutions, therefore the baths are disposable.
The reserve solution is kept excellently in acid solution (such as sodium bisulfite or
potassium or sodium metabisulphite). Soluble in water, but also in alcohol, ether and acetone.
We begin our exploration of the pyrogallol with one of the most famous formulations, the ABC pyro or Kodak D-1. The name ABC derives from the three necessary solutions.
This formulation has been used by almost all photographers. From Weston to Adams, everyone used their own formulation or dilution. Let’s see the classic formula.
How to use
The standard tray dilution of this development is 1: 1: 1: 7, while the tank dilution is the following 1: 1: 1: 11. I recommend this development, however, only to those who use the large format, as it tends to apply the grain of the film. There is also a loss of sensitivity by the emulsion, which makes this type of development very good for inspection development.
In preparing the development solution, solution B must be added to the water first, then solution C, leaving solution A separate. Then we will add the latter only before starting the development of the film. This greatly avoids oxidation.
In the use of this development, it is necessary to pre-bathe the films in water, not very long, 2 minutes are sufficient. Another crucial point is the agitation of the films in the bowl. If it is not well done it can cause streaks on the negative.
The tray that invention
Many photographers recommend developing one film at a time, so that the film comes out of the solution as little as possible. Being the air a source of oxidation. When you have large batches of films to develop, this system is long and takes too long. I personally develop batches of 8 to 12 sheets of film all together. Using slow and continuous stirring. If you want to know my way of development read this article
After we have developed our negatives, before moving on to the stop in acetic acid, it is useful to pass the negatives in a basin of water only. This will minimize the possibility of micro explosions on the emulsion, which cause small holes, due to the sudden insertion in a very acid environment such as the stopping bath. I personally also dilute the stop bath twice as much as normal.
As regards the fixing, a negative developed in pyrogallol, does not require a hardening fixing. One of the best fixings that can be used with this type of development is the Kodak F-24.
ABC and zonal system and photographers
However, the development of ABC is said not to be very suitable for the zonal system, as regards the extension or contraction of the areas, as it is not very controllable. I do not agree very much on this point, given that the normal dilution results in an excellent contraction or extension of the areas.
We can also control the energy of development quite well by acting on carbonates. Reducing them will have less energy, this will decrease the contrast, while increasing them we will increase the contrast. Obviously this will affect development by making it less stable.
Personally, I always keep a little solution C, ready to add to the development in case of negatives that need a sprint in greater contrast.
Many photographers used this development, Adams, Weston, Strand, Wynn Bullock, some of them created variations on the standard recipe. Ansel Adams, for example, left solution A identical, while in solution B he used only 75 grams of sodium sulfite instead of 105. In solution C he used only 87.75 grams instead of 90, a rather negligible difference. The 30 grams in solution B can have effects on the life of the solution and on the overall acuteness, but it has no effect on the tonality.
Edward Weston instead used the standard solution, but changed the dilution, using 3: 1: 1: 30, the development times were very long, but the large amount of solution A, mitigated the effects of oxidation. According to Weston, this type of dilution gave his negatives a better tonal scale. I have tried this dilution, and it is very mild. The negative need for an overexposure of at least 2/3 diaphragms, under penalty of an underexposed negative. Development times start from 15 minutes onwards at 21 degrees.
The PMK development is due to Gordon Hutchings, a pyrogallol / metol developer, which uses Sodium Metaborate as alkali. It is a detector created for modern films, which enhances sharpness, fineness of grain. A very interesting detector, both for enlargement and for contact printing, or for ancient techniques.
PMK requires some peculiarities in the treatment, but we will see them later. Let’s start with the formula
How to use
The standard dilution for PMK is 1: 2: 100. Development in the tank requires rather vigorous shaking. I personally use two tank reversals every 15 seconds. This greatly minimizes oxidation problems and any stains or streaks on the Negative. While in the tray I prefer slow and constant stirring.
This type of development is not indicated for use in Jobo rotation systems, not being created for this type of system. But nevertheless I had no problems using it by changing the dilution. Hutchings suggested the use of EDTA in development, this facilitates use in rotation systems, but at the expense of a loss of coloration of the negative. Personally I preferred to use the 1.5: 2: 100 dilution, I have used in Jobo systems with good results. Obviously I recommend if you use these rotation systems, the use of PMK optimized for Jobo (Rollo Pyro or Max Pyro).
For an excellent coloring of the negative, you can use a very diluted 28% acetic acid stop bath, or just water, but especially in the latter case, stirring constantly.
The fixing must be of the non-hardening type, this minimizes the loss of color of the negative. An excellent fixation is the Kodak F-24. Another possibility is given by basic or neutral fixings. These allow an excellent compromise, without having negative color loss problems. Two excellent fixings that you can prepare yourself are TF-2 with sodium hyposulphite and TF-3 which uses ammonium thiosulfate instead. Photography formulary in its price list has the TF-4 and TF-5 which are very good for this type of development.
and for coloring
My primary choice, however, remains the Kodak F-24, which is an excellent fixing for negatives and for paper. The basic or neutral fixings, however, have the advantage that they are more easily eliminated from washing. Once the negative is fixed, it is recommended to put the negative back in the used developer, this should increase its coloring. The time spent in used developer is 2 minutes. Using PMK, many times I have omitted this practice, and I honestly haven’t found much difference.
The film must not undergo the passage in the hyposulphite eliminator, since this consists of the majority of sodium sulphite, it would tend to eliminate the coloring of the negative. So after fixing, and any passage in the development used, it must be washed under running water, you will notice a very slight increase in coloring during washing.
Max Pyro developer is a version released recently by Hutchings. This developer is created to fully exploit the sensitivity of the film, generates little veil, has a good coloring, and can be used in tanks, basins and Jobo. It adapts well to any type of photography, enlargement, alternative process or other.
This new development works well with each film, but makes ideal use of the fastest films, such as Hp5 / Tri-x / Tmax 400.
As for PMK, the development is in two solutions, solution A contains pyrogallol, in this case with a very high quantity, while solution B we find alkalis. This new formulation is much more active than PMK, so we can run into very dense negatives if we use a different ISO than the one provided by the manufacturer. Development times vary from 7 minutes for faster films, to 5 minutes for slower ones.
To have an N +, Hutchings recommends reducing exposure by 1/2 aperture and increasing development time by 40%. While for an N- add a stop and reduce by 30%.
The formulation is quite complex, and some chemists are difficult to find. I do not provide the formulation not knowing it perfectly. It can only be purchased from Bostick & Sullivan.
Although the pyrogallol, is an old man in the panorama of developers, and that his difficulty at times may seem excessive, continues to have a great impact in photography. The formulations, even if dated, adapt to the new films, new formulations are born in order to exploit the characteristics of the most modern films. Surely this old young agent will continue to keep us company for a long time, accompanying new photographers to discover the qualities and those small differences that this type of detector can provide
|distilled Water||400 ml|
|Sodium Bisulfite||10 gr|
|Water to make||500 ml|
|Distilled Water||700 ml|
|Sodium Metaborate||300 gr|
|Water to make one liter|
|Standard diluition 1:2:100@20°|
|Water @52°||500 ml|
|Sodium Thiosulfate||240 gr|
|Sodium Sulfite||10 gr|
|Sodium Bisulfite||25 gr|
|Water to make one liter|
|Use it in Stock solution|
|Water @52°||750 ml|
|Sodium Thiosulfate||250 gr|
|Sodium Sulfite||15 gr|
|Sodium Metaborate||10 gr|
|Water to make one liter|
|Use it in Stock Solution|
|Ammonium Thiosulphate 57-60%||800 ml|
|Sodium Sulfite||60 gr|
|Sodium Metaborate||5 gr|
|Water to make one liter|
|Standard Diluition 1:4|
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Photography Formulary – Chemical and materials for photography
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