I not sure how to answer your question. I have been using Hutchings formula for my clients and myself. the conclusion I have came to that this is the case to *bump up the filter *to print a pyro neg. I believe that Hutchings book says this as well.
I have literally seen every film exposure, development time compensation on a Jobo that one could imagine using Hutchings Pyro.( In almost every case a grade 3 filter or 2 1/2 is best suited for the image.
From college days I have assumed that a assumed *good negative* that has been processed in a non staining developer like D76 a good starting filter pack is grade 1 or 1 1/2 give or take.
As you may be aware I am dealing with a client base that is varied and from different skill sets, but I have always noted this increase of required filter.
Probably the most underated factor of Pyro *tannin* developer is the fact that as development occurs there seems to be a hardening effect that happens around the silver that stops migration in the highlights. This is what I believe to be the single most important factor why one would use a Pyro developer. I believe this is the reason that the highlights are sharper with pyro as well with the extended development times the highlights seem to stop develping or migrating . Shoot a room with a bare light bulb in the scene and overexpose for the shawdows and drop process. If you use two different developers pyro and D76 , my experience tells me that the pyro neg the bulb will be more defined and as well you will have captured more shadow detail.
When I balanced in for Pyro there were major learing curves and yes we did plot the curves ect. But since 94, I and others at my shop have been experimenting with Mr Hutchings concoction and have used his book as a constant reference. We have tackled many problems with Pyro, it is as he stated in his book a developer not for the feint of heart. His warning is real and it has taken years for our shop to iron out the bugs. We have done countless print shows that were developed in pyro and believe that it is a very potent weapon in the developer selection process. I have spent a lot of time looking at negatives on light boxes and projecting on a easel and frankly I can only argue my points on this level. I have a technicion on staff who can plot and keep in balance any process required. * but sadly he couln't make a show print if his life depended upon it.*
Sandy, I have rambled on , and to answer your question , bluntly I do not know why I am using a higher filter for pyro negs over d76 negs , just that when I am making prints this is always the case. I would love to have a conversation with Mr Hutchings on this and talk to him about our methods and see if they match his as I have ran a lot of pyro in this shop and through daily experience I have noticed certain differences between pyro and d76.
Others , yourself included may have a more scientific outlook on this and I respect that. But from a day to day observation I have always found the above to be true.
One last observation. Pyro in my estimation sucks if you want to push process. exp underexpose and overdevelop. Why I am not sure
I was always under the impression that it is good to develop for a grade 2 print (your paper of choice, VC, graded, azo, etc.) which then gives plenty of latitude for expressive printing. I've switched from PMK to pyrocat, mostly due to murky shadow values with PMK. Highlights were never a problem, but shadows were.
I wonder how many people actually test a film - developer - paper combination to find out how things work? tim
I do. I also switched from PMK to Pyrocat and will not go back. This is a very nice developer for vc paper.
Make sure you test! I have no idea if my temperature is correct because I have a really cheap thermometer. (And I think it should be 72 and not 70 as I stated above.) And I use a condenser enlarger, and I have a really old densitometer that doesn't do color, and I'm metering with my Fuji camera, etc., etc. Many variables to consider. Also, I use 1:1:100, but you might get better results with 2:2:100. When I started using pyrocat-hd I used 2:2:100 but switched because I like the longer development times.
Originally Posted by Will S
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"I am an anarchist." - HCB
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If you have developed any properly exposed film with any developer to the proper contrast, they all print the same with very close times.
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Originally Posted by Bob Carnie
I may have not been clear with my question. I understand why D76 and PMK negatives print differently on VC papers. Hutchings explains it well in The Book of Pyro: the yellow/green stain functions as a low contrast filter, increasing proportionally with silver density. All pyro developers share this characteristic, though the color of the stain makes for small differences in results.
My question was, since you know that the PMK negatives, devleoped for whatever time you develop, give negatives that require a #3 or #3 1/2 filter, why don't you just develop the negatives longer and calibrate for a #2 filter? I could understand that if you are printing with both graded silver papers as well as VC papers you might want to develop for the graded papers and get the extra contrast for VC papers with the filter, but if you are only printing on VC papers why would not just develop longer so that the effective printing contrast is the same?
Ok , I see where you are going with this, good question.
right now I am doing a 14 minute development for trix based on 200ISO,
my fear is that anything over 16minutes I may not see any difference. I am using two 1litre mixtures of chemicals split into 7 minutes for each on the Jobo. and my worry is that over 16 minutes I have exhausted the useful developer.When I started with Pyro I found that 1 litre was exhausted too quickly and resulted with underdeveloped negatives, therefore the split 1litre system I use.
In fact I use a *biggie size * Pyro version for certain clients , 25-A 50-B rather than the 20 and 40 recommended by Mr Hutchings. This seems to give an extra kick to produce the negatives I require for printing.
As I have stated I have not used pyrocat so I do not have an opinion on its properties, but with Mr Hutchings formula I have found my comfort level.
Your suggestion of extended development to produce a negative of a paticular contrast to produce a print of grade 1 1/2 is very valid , I just don't know how to do this with my experience of how Mr Huchings formual works with a Jobo processor.
One thought would be to increase agitation , and or developer temp, but to this date I have been happy increasing the filter grade.
Your thoughts would be appreciated
Bob, I would urge you to try Pyrocat as an alternative, just to see what the difference really is. I spent 2 years with PMK as my only developer, before trying Pyrocat. I know that in business "If it ain't broke, don't fix it" is the rule and that money doesn't grow on trees.
Just for a comparison, you might consider this developer as it is economical, easy to use (a&b, similar to what you already measure) and gives great results. You won't have the problem with depletion in processing and can tailor times to grade 2. tim
One thought that immediately comes to mind is to increase the ratio of Stock A solution in the working developer. For example, instead of mixing PMK 1:2:100 try 1.5:2:100, or even 2:2:100. The greater amount of Stock A in the working solution will reduce oxidation, and the resulting B+F that we see with rotary processing. You could also add a very small amount of ascorbic acid to the working solution, though this may change the working characteristics of the developer. In the Book of Pyro, for example, Hutchings observes that the use of ascorbic acid in a superadditive mix with pyrogallol resulted in a loss of apparent sharpness.
Originally Posted by Bob Carnie
I could be wrong but my impression is that PMK was not designed with rotary processing in mind, so there are some problems that this type of development introduces that were not thorougly researched. This justifies, at least in my opinion, minor adjustments to the formula to make it work best for your application.