Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,942   Posts: 1,585,749   Online: 1134
      
Results 1 to 2 of 2
  1. #1

    Join Date
    Nov 2004
    Location
    Bilthoven, The Netherlands
    Shooter
    4x5 Format
    Posts
    1,858

    Hig Definition Developer, Staining and Non-Staining

    HIGH DEFINITION FILM DEVELOPERS

    by Jed Freudenthal


    High definition film developers belong to the classic film developers. Although there are many formulas, the Kodak D-1, or ABC formula is a classic formula. According to Anchell (1): 'ABC is one of the most difficult and fickle pyro formulas to use. It is recommended only for large-format negatives, but used properly, the results obtained are unequaled, even by most other pyro formulas, in tonal gradation and subtle high light separation'.
    In the 1920's the 35 mm has been introduced to make photographs. The grain of the negative had to be reduced, and the D-76 family of film developers was the result. Developers with another character than the classic high definition pyro developers. The ease of use made this category of film developers popular, even for the larger size negatives.
    Nevertheless, research went on to improve the properties of the high definition developers. In the first place, the reliability of the developer needed improvement, secondly the grain had to be reduced. And, if possible, the properties in the deep blacks could be better.
    Well known is the work of Hutchings (2) who developed the PMK ( pyro-metol-kodalk=sodium metaborate) formula. This high definition developer is rather reliable and suitable to use with 35 mm film. In this developer adjacency ( or Eberhard) effects increase the local contrast, giving the suggestion of a 'sharp' image. It is a matter of taste, but the image quality is often degraded by this 'sharpening effect' by the developer.
    There is a range of other approaches to get a high definition film developers, not necessarily based on pyrogallol.

    In this research our first goal was to modify the classic ABC pyro formula in such a way that it would be reliable to use for large format negatives and to improve the high definition effect. [pyro HD developer].
    Then in a second step our goal was to reduce the grain size and the base line fog for better shadows in printing. This is the catechol HD developer. The two high definition film developers have different characteristics. Depending on the application, a choice can be made.

    MODIFICATION ABC FORMULA [pyro HD developer]

    The modified formula is:
    ( USE GLOVES FOR MIXING SOLUTION A, AND DO NOT BREATHE PYROGALLIC ACID DUST)

    Solution A
    distilled water ( not over 26 ºC) 750 ml
    potassium metabisulfite 9.8 g
    pyrogallic acid 60.0 g
    potassium bromide 1.1 g
    Cold water to make: 1.0 l

    Solution B
    sodium sulfite 20weight % stock solution
    (20g sodium sulfite anh. and 80 ml distilled water)

    Solution C
    Water 1.0 l
    sodium carbonate, monohydr. 90.0 g

    To make 1.0 liter developer:

    Filtered tapwater 891 ml
    A=52 ml
    B= 1.0 ml
    C=56 ml

    Add the solutions A, B. and C to the filtered tapwater just before the development process starts. Development time is around 11 minutes at 20 ºC, depending on type of film.
    Agitation: Invert the tank the first 30 sec, then invert once every minute during 10 sec.

    Buffered Stop bath
    water 1,0 l
    28% acetic acid 120 ml
    sodium acetate 80 g

    The filmholder will be around 4'' in the stop bath

    Alkaline fixer ( modified TF3 fixer)
    ammonium thiosulfate 57-60% 800 ml
    sodium sulfite anh. 60 g
    sodium metaborate 6 g
    water to make 1 liter
    working solution : dilute 1:4 with water

    Fixing: 5'

    Rinsing and drying the film

    Notes:
    1.The most important modification in this developer is in stock solution B. This solution is quite stable and because the concentration is of the sodium sulfite is low, the high definition effect is high. The dry sodium sulfite anh. has to of good quality. Don't use degraded sodium sulfite anh. The amount of the sodium sulfite is small. It has a conservation property, and it will not attack the grain in the emulsion. The developer is a non-solvent, high definition, tanning developer. The tanning effect ( due to the low sulfite level) probably contributes to the positional stability of the negative image. And therefore to the high definition effect and the image quality.
    2.I found that filtered tap water gave good results. Filter paper or paper coffee filters can be used for the filtering process. However, tap water quality may vary. Therefore test the tap water by making a comparison using demineralized or distilled water.
    3.The potassium bisulfite can be replaced by sodium bisulfite; the color of the stain will be different. This may be useful when prints are made on variable contrast printing paper.
    4.Use conventional type of films. Do not use tabular films.
    5.I use the Combi Plan tank for the development process. The film holder with films is put in the empty Combi Plan tank. The tank is opened in the dark and the developer, mixed in a beaker, will be put at once in the tank. The tank is closed. The light is on and the development process starts. Just before the end of the development process, the light is off . The tank is opened in the dark and filmholder will be transferred to other tank filled with the stop bath. Then after the stop bath process, the film holder is transferred to an other tank filled with fixer. The tanks filled with fixer and stop bath are made out of PVC. But other Combiplan tanks could be used as well.
    6.The filmholder with films can be put in the alkaline developing bath back for 2'30'' after the fixing process. This will enhance the stain. [This stain will mask the irregular noise due to the restraining effect of the potassium bromide. It has a positive effect on the image quality in the deep blacks.] After this, the film has to be rinsed.
    7.Pyrogallic acid is toxic and has a strong staining effect. Thefore use gloves during the development process. Don't spill the developer. It may cause stains. In preparing the stock solution A, use a mask to prevent breathing pyrogallol dust when the pyrogallol is added. Reduce the formation of pyrogallol dust. If mixing is done outside, do not mix in a windy area.
    8. The distilled water in solution A may be replaced by demineralized water. The potassium metabisulfite may be replaced by sodium bisulfite.


    The pyro developer described above is beautiful in its tonal gradation and subtle highlight separation. It has a picturesque appearance. The grain is masked by the stain, which is proportional to the densiity of the silver image. In addition, there is a general stain resulting in a good black compression and masking irregularities in the base line fog. Disturbing adjacency effects do not show up.

    In the second step of the development of high definition film developers, the grain has been reduced and the separation in the shadows has been improved by reducing the baseline fog. This developer is based on pyrocatechein or catechol. An additional advantage is that the toxic effect of pyrocatechein is less than that of pyrogallol, because it causes less dust than pyrogallol. The use of gloves is still recommended. The staining effect of pyrocatechein is much less than that of pyrogallol.

    FORMULA OF THE PYROCATECHEIN FILM DEVELOPER
    [ Catechol HD developer]

    filtered tap water of 20 ºC 810 ml
    sodium sulfite solution B 1.0 ml
    pyrocatechein 1.44 g
    potassium carbonate solution 180 ml
    Add filtered tap water of 20 C to make 1.0 l


    Notes
    1.The potassium carbonate solution is a 75 g/ liter filtered tap water solution.
    2.sodium sulfite solution B is the same solution as used in the ABC formula above.
    3.The amount of pyrocatechein is given in two digits, because of the properties of my scale. The amount pyrocatechein is not that critical
    4.The developer is non staining and gives a fine grain. A 10 times magnification on a HP5+ ( 400 ISO) is possible without significant effects of grain.
    5.The development times at 20 ºC is around 11-12'.
    6.The exposure of the film is the same as for a developer like D 76 for e.g. Ilford films like FP4+ and HP5+, but there are films like Fortepan 200 and 400, that require 2x more exposure.
    7.The development process for sheet film in Combiplan tanks is the same as described above for the pyro developer. The development process for films in Paterson-like tanks is the same as for the Combiplan tank. However the stop bath and fixer are put in the same tank.


    Buffered Stop bath
    water 1.0 l
    28% acetic acid 120 ml
    sodium acetate 80 g

    The filholder will be around 4? in the stop bath

    Alkaline fixer ( modified TF3 fixer)
    ammonium thiosulfate 57-60% 800 ml
    sodium sulfite anh. 60 g
    sodium metaborate 6 g
    water to make 1 liter
    working solution : dilute 1:4 with water

    Fixing: 5'

    Do not stain after the fixing. There is no stain.

    Rinsing and drying the film.

    The characteristics of this non-solvent high definition developer is the relatively small grain and good separation in the highlights as well as in the shadows. Therefore, this developer is particular useful where separation in the shadows is important, like e.g. in landscape photography. The character of the photographic image on the negative can be controlled through the selection of the film type and photographic lens.

  2. #2
    Sean's Avatar
    Join Date
    Aug 2002
    Location
    New Zealand
    Shooter
    Multi Format
    Posts
    8,594
    Blog Entries
    7
    Images
    15
    Comments from previous article system:

    By Tom Hoskinson - 03:22 PM, 02-14-2006 Edit Rating: None
    Jeff Pyrocat-HD will meet (and/or exceed) all your goals. Plus, it has the additional advantage of long stock solution shelf life and there is a enormous amount of data on its performance with many different films. This data includes the performance of Pyrocat-HD with tabular grain films (Pyrocat-HD works very well with them)
    By Tom Hoskinson - 04:07 PM, 02-14-2006 Edit Rating: None
    Jeff, you state "6.The filmholder with films can be put in the alkaline developing bath back for 2'30? after the fixing process. This will enhance the stain. After this, the film has to be rinsed."

    If you do this, the overall stain will increase, but the image forming stain will not. Gordon Hutchings is no longer recommending this practice for PMK development.
    By Jed Freudenthal - 08:00 AM, 02-15-2006 Edit Rating: None
    I published a combo of two HD developers, each with their own specifications and with their own image quality. The specifications complement each other. One can never put contradictory specifications in one formula, whatever the formula. Therefore, one cannot compare one developer with a combo of two. The difference of the two HD developers is obvious in the final print. However, I plan to determine the MTF behaviour of the two developers with different films. I developed this combo because I was unable to catch the great wealth of light circumstances in Europe. I tested the combo where the great painters of light went to. First of all, the Netherlands with the Dutch light; then France the land of van Gogh and Cezanne, Italy at Sorento and Cornwall in England. In these areas, I think, one should test a high definition developer.
    It is right that the overall stain will increase too when the film holder is put in the alkaline afterbath back. But this is one of the parameters one can vary in the modified ABC formula. It will influence the tonal separation in the shadows.

    Jed
    By Jed Freudenthal - 08:36 AM, 02-15-2006 Edit Rating: None
    I focussed on QA aspects, rather than shelf life. The shelf life of solution B of the ABC formula is an example of problems. The PMK is better, the older it is; it is just like fine chesse or wine. Some people mix their developer with old developer. And so on. I could have put the pyrocatechein in solution, but study the chemistry of pyrocatechein, I thought I better add it just before development. In other words: shelf life is a vague concept. But again: MTF tests will be used to determine real stability.

    Jed
    By Tom Hoskinson - 01:15 PM, 02-15-2006 Edit Rating: None
    Jeff, please publish sensitometry and densitometry data for these developers so that we can compare it with the other published film/developer data. I'd like to see your data for Kodak TMAX 400, Efke 100, Ilford FP4 Plus and Fuji Acros.
    By titrisol - 02:04 PM, 02-15-2006 Edit Rating: None
    This is funny, I just read an article about the Pyro developers in one of the old PhotoVision Magazines.
    By Jed Freudenthal - 08:53 AM, 02-16-2006 Edit Rating: None
    Tom, as I said, I will make densitometric (Modulation Transfer Function) measurements in the future. I hope soon. In the past, I had a microdensitometer in my lab; unfortunately that is not the case anymore. However, when we had an APUG 'pub'meeting of the Dutch group one week ago, I discovered that one of our professional members has the instruments in his lab, to provide the photographic industry with data. He told me, I could use his instruments. So, you can see, we not only drink beer in our pubs!
    To speak with the people in the 'Kodak research labs': The image quality of the final print will be determined by the MTF's of the different parts in the chain. This applies in particular in high definition imaging. PMK, and likewise pyrocat HD, are developers with two developing agents. As you can expect from these developers, they have adjacency (Eberhard) effects. I expect an discontinuity in the high spatial frequency range in the MTF. It is a matter of taste, but many people experience this as unpleasant in the final image quality. This is, why the sharpening up in computer image manipulation is hardly used today. And that is the reason that I have focussed on developers with one developing agent. It is not without reason that the staining ABC formula is such a beautiful developer. And notice that my pyrocatechine formula is a non-staining formula.
    Anyway, I have to make a research program in the near future. You asked me to include the T max 400. Do you mean the present (last year) version? I usually work with FP4+, HP5+, Fortepan 200, 400, Tri-X, 320 and 400. Then adding PMK and pyrocat HD would be nice too ( I have them in my lab). But, .... I still need some time to do the real work: photography.

    Jed
    By sanking - 04:26 PM, 02-16-2006 Edit Rating: None
    Jed,

    You suggest that developers like PMK and Pyrocat-HD that have two reducing elements are more likely to produce adjacency effects than a single reducer developer like ABC. What is the basis for this observation? I have not seen this stated before and don't understand the theory of why it would be so. If you could cite a source for this I would be most appreciative.

    Sandy
    By Tom Hoskinson - 06:30 PM, 02-16-2006 Edit Rating: None
    Jed, You state:“4.The developer (referring to your Catechol Developer Recipe) is non-staining.”This is difficult for me to understand given the small amount of Sodium Sulfite your Catechol Developer recipe contains (i.e, 1 ml of Solution B).Catechol/Pyrocatechol together with low sulfite, produces image stain that can be difficult to see by visual examination of the negative but which produces a significant increase (increase proportional to the amount of exposure) in the UV density of the silver image.Have you confirmed with transmission densitometry that this developer does not stain the silver image?
    By jdef - 04:22 AM, 02-17-2006 Edit Rating: None
    Jed,

    you might have a look at my developer formulae here:

    http://www.digitaltruth.com/techdat...stainingdev.php

    it seems we had similar goals in mind, but very different approaches to the problems involved. Thanks for posting your formulae.

    Jay



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin