The Advantages of Pyro for Platinum Printing

                                                                    © Bob Herbst 2002

 

 

(This article originally appeared in the September/October 1997 issue of View Camera magazine.)

 

My interest in pyro pre-dates my foray into platinum printing.  I was originally drawn to pyro after seeing some silver prints from pyro negatives.  The sharpness of the image was extraordinary and the specular highlights were dazzling.  I couldn’t have known at the time that this new developer would be a factor in a major change in  direction in my photography - a complete shift to platinum printing.

 

I began my experimentation with pyro using the standard ABC formula but found the loss of film speed and weak shadow detail to be unacceptable.  Never the less, the potential I saw in how this century old developing agent rendered the mid-tones and delicately separated highlight values kept me interested in pursuing pyro further.  After some reading, some experimentation with Wimberly’s pyro-metol formula, and a phone call to Gordon Hutchings, I arrived at a pyro-metol formula which has remained unchanged since.

 

A year or so later, I started printing in platinum/palladium.  When I learned the process at a local university, the first thing I noticed was that my print times were considerably longer than my classmates, who had used HC110 or other common standard developers.  Other differences between my work and that of my classmates became apparent fairly quickly as well.  The instructor’s advice to significantly increase development time on the negatives did not seem to be required for me to obtain good platinum prints.  I was suddenly able to obtain beautiful prints from rather thin negatives, negatives from which I had never been able to get a good silver print.  Highlights, especially in clouds, showed a very fine separation of values.  My prints also showed a better separation in the middle tones and held shadow detail better those of my classmates.  All of these characteristics can be directly attributed to the use of pyro and the stain it produces.

 

The key reason why pyro is such a wonderful developer for use in platinum printing is the stain.  Pyro stain is yellowish/brownish and varies slightly with the formula used.  The yellow stain has a very prominent effect in the platinum printing process.  Basic filtration tells us that yellow blocks blue. Platinum/palladium solutions are sensitive only to ultraviolet light - essentially blue light.  Consequently, the yellow stain has an even greater effect in printing platinum than for silver printing where green light is also used.  The yellow stain acts as additional density as in silver printing but its effect is far more pronounced for platinum printing.

 

My formula and processing practices do not necessarily follow the philosophy of maximum stain/minimum silver.  The pyro-metol formula is identical to Wimberly’s W2D2 formula except for the restraining agent in solution B.  The formula is as follows:

 

            Solution A

            Distilled Water (at 125 deg. F)  1 liter

            Metol                                                   3 grams

            Sodium Bisulfite                                    10 grams

            Pyrogallol                                             30 grams

 

            Solution B

            Distilled Water                                      1 liter

            Sodium Carbonate (monohydrate)        40 grams

 

Originally, I included 1.1 grams of potassium bromide in Solution B as a substitution for Kodak anti-fog which was called for in the original W2D2 formula.  I had difficulty obtaining sufficient contrast in the resulting negatives and development times were exceedingly long.  On the advice of Gordon Hutchings, I eliminated the bromide which solved both problems.  I have not noticed any fogging problems after a couple thousand 4x5 and 8x10 negatives.

 

I use TMAX 400 in 4x5 and 8x10 exclusively for my platinum negatives.  Its pronounced contrast and beautiful edge effects are a perfect combination for platinum.  I have tried Tri-X and found results similar to TMAX but the reciprocity characteristics requiring ever increasing exposure in low light situations make long exposures difficult to manage.  Many of the exposures inside the cathedrals required 10-30 minutes on TMAX 400 which would have been at least an hour or two with Tri-X.  Also, edge effects do not seem nearly as pronounced with Tri-X as with TMAX.  I rate TMAX 400 at 200 and reduce development to maintain good fat shadow detail yet printable highlights.

 

Negatives are developed in trays - eight 4x5 sheets or four to six 8x10 sheets at a time.  The number of sheets is based on how many I can comfortably shuffle through in a 30 second cycle without scratching negatives.  Agitation is constant in that I am constantly moving the bottom sheet to the top of the pile throughout the development process.  The negatives are presoaked in water for 2 minutes and then transferred to the pyro.  My standard developer dilution is 1:1:15 for solutions A, B, and water respectively.  This dilution seems to work well for normal and both minus and plus development of negatives.  For normal negatives, I develop TMAX 400 at 68 degrees for 15 and a half minutes plus 30 seconds to displace the water from the presoak.  I have not tried other dilutions since this one has served all of my needs.  The negatives are developed emulsion side up and half way through the development time, I rotate the stack 180 degrees to even out development.  Otherwise the end of the negatives that are lifted to remove the bottom negative from the stack tend to get slightly less development since they are repeatedly lifted above the surface of the solution even if only for a brief moment.  I have tried emulsion side down development but had too many scratches in the negatives which I can not completely explain.

 

A tray of distilled water is used instead of an acid fixing bath.  I figure any developing action which continues before the negatives hit the fixer only enhances the shadow detail with very little effect on the highlights.  I started this practice when I was having some problems with my development process and was trying to eliminate variables.  I saw no significant differences between an acid stop and a water stop bath so I stayed with the water.  It is cheaper particularly since the stop bath must be discarded after each process cycle because of the oxidized pyro carry over from the developer tray.

 

Contrary to  most of the experts’ recommendations I use a pre-packaged hardening fixer, Kodak Fixer(gasp!), which undoubtedly removes some of the stain.  Some day I may move to mixing my own fixer for economy but prefer to pay a little more and spend my time on the creative process rather than mixing chemicals.  Fix TMAX 400 for 10 minutes in Kodak Fixer.  Some of the pink anti-halation dye will remain after the fixing bath but this will disappear after hypo clearing agent and washing.  Use fresh fixer for each batch of film or a two bath method with the second bath used as the first bath for the next batch of film.

 

I can not provide any density charts or film characteristic curves for my film/developer combinations under my process.  There are many such analyses available in books and articles.  The Book of Pyro is probably the best reference source for this information.  I ran all of those tests years ago but my test results did not seem to yield any improvement in my negatives or prints. My black and white transmission densitometer was useless for pyro negatives because of the stain.  I also got tired of spending all of my time running calibration tests which did not seem to improve the quality of my prints.  I sold the densitometer and started working from instinct based on the philosophy of standardizing on my materials and learning their behavior and characteristics under varying conditions.  I continuously make minor adjustments in my developing times and procedures to improve both negative and print quality and consistency.

 

I may not follow all of the standard formulas or rules, but I am very satisfied with the resulting prints.  I was tempted to try Gordon Hutchings PMK formula when his book came out, but I believe in the old adage, “If it ain’t broke, don’t fix it” so I continue to use my own formula. Pyro will provide benefits for the platinum printer regardless of the specific formula.

 

While pyro can be a valuable tool for the platinum printing, it can get out of control, and very quickly.  Because of the greater effect of the yellow stain on ultraviolet light, the most important factor in obtaining consistent negatives and prints is a consistent processing regimen and timing of the process.  Pyro quickly begins to oxidize as soon as the developer and alkali are mixed.  The longer the developer is exposed to air, the darker it becomes and the deeper the resulting stain.  Pyro that has been sitting in an exposed tray for 30 minutes before use will yield a very deep stain and will also result in a much darker silver image as well.  I discovered this when a friend called just after I poured some mixed pyro developer into a tray and didn’t start development for a half hour.  The temperature was still constant so I decided to use it.  I would describe the resulting negatives is “bullet proof”.  One of the negatives requires over 45 minutes of exposure in a high intensity platinum printer to obtain enough print density.

 

Although a potential pitfall, this characteristic of pyro can also be exploited. Increasing the developer temperature or using a highly oxidized developer can be used for “plus” development.  A negative which needs the contrast punched up a bit can be developed in an overly oxidized solution.  Also, after development and fixing, you can immerse a negative in heavily oxidized pyro developer with constant agitation to increase the overall stain density of the negative. The silver density does not change because the negative has already been fixed.  This can be useful to salvage a thin negative, or to increase contrast slightly in the low values.  A dried negative can be re-wetted and immersed in oxidized developer to produce the same effect.

 

The developing action of pyro and the associated stain effects are very sensitive to small variations in developer temperature. Pyro oxidizes more rapidly as the temperature of the solution increases.  If you tray develop, use a water bath around the trays.  Without a water bath, a 68 degree solution will easily climb to 70 degrees during development just from heat transfer from your fingers.  If the air temperature in the room is higher than the developing temperature, the solution temperatures will gradually rise as well without a water bath.  A two degree increase in developing temperature can have a significant effect on total negative density for a pyro negative.  The accelerated action of pyro on both silver density and increased stain is additive in the resulting negative and therefore has an almost doubling effect as if the negative had actually been developed even longer.  The increase in stain has the greatest impact for platinum printing.  Pyro does not oxidize as quickly in a full closed tank.  The staining effects are less pronounced for the same development time which must be taken into account when developing roll film intended for platinum printing in pyro.

 

On the business and logistics side of my photography, a major benefit of pyro is being able to obtain a good platinum print and a good silver print from the same negative.  This is very difficult when standard negative developers are used because the platinum negative must be “over-developed” relative to a silver negative with the same developer. This characteristic of pyro comes in very handy when you need to provide 8x10 glossy silver prints for exhibition announcements, press releases, and for other promotional purposes. And, even though 95% of my work is platinum, I do occasionally shoot with the intent to print a negative in both silver and platinum and I do not have to develop two negatives differently for each print medium.

 

Pyro has seen a resurgence in recent years which is probably in part due to Gordon Hutchings’ book, The Book of Pyro.  While pyro is an old and dependable developing agent, it is easy to see how lack of attention to consistency in developing practices can have dramatic effects on the resulting negatives.  Difficulty in maintaining processing consistency has been one of the major criticisms of pyro over the decades.  I have found that if you already have control of your developing process, pyro is a very manageable developer that brings only advantages for platinum printing.  Many of the characteristics and subtle nuances of pyro also apply to silver printing, but pyro has proven for me to be the perfect developer for the platinotype.