Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,550   Posts: 1,544,729   Online: 977
      
Page 13 of 16 FirstFirst ... 378910111213141516 LastLast
Results 121 to 130 of 160
  1. #121
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,289
    Images
    20
    If you weren't using enough fixer, that would be pretty easy to determine empirically, and presumably anyone interested in the two-stage approach would try it out first before processing anything important this way. I suspect that unless someone used a very strong developer and way too little fixer, which doesn't strike me as a probable scenario, the worst case result would be a little underfixation that could be easily remedied with a clean fixing bath. A dilute one-shot developer seems like a much more likely candidate for use in two-stage processing. The developer should be close to exhaustion when the fixer is added to avoid the sludging and plating out problems that are characteristic of monobaths.

    Also, the normal fixer ratio presumes the fixer is going to be reused. For one-shot fixation, I suspect you could get away with less.
    Last edited by David A. Goldfarb; 09-04-2009 at 10:18 AM. Click to view previous post history.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  2. #122

    Join Date
    Apr 2007
    Shooter
    Large Format
    Posts
    26

    A simple two-ingredient monobath

    In post #47 above, Photo Engineer notes “D76 can act as a monobath for pure chloride emulsions”.

    Although it is probably more of a historical curiosity than a truly useful formula, just for fun I am going to raise the stakes, draw only two cards, and trump D76 with a modified form of D23!

    In 1964 William Walker from Calcutta took out a patent (GB960872, assumed to be equivalent to US patent 3,155,508, which is available online) for a tropical developer, which he prepared by boiling (for between 1 to about 30 minutes) 140-160 parts by weight of anhydrous sodium sulfite and 2.5 to 20 parts of metol to make 1000 parts of solution.

    Walker’s Example 3 formula consists of 0.25 parts metol and 16 parts sodium sulfite in 100 parts water. According to A. A. Newman, “Progress in Monobaths,” Journal of Photographic Science, vol. 15 (1967), p. 128: “Applied as a stand solution at approx. 100F [38C] for a period of 30 minutes or less [only 10 minutes, with agitation every second minute, in Example 3], it will act as a developer, but by extending the processing time to 3.5 – 4 hours [with agitation for two minutes every hour in Example 3], it will behave as a monobath! It is claimed that, notwithstanding the high processing temperature, an emulsion immersed in the bath will be hardened rather than softened.” Haist, Monobath Manual, p. 153, indicates a chrome alum hardening bath was used before washing, but Walker definitely doesn’t mention this in the American version of the patent, where Example 1 is intended to demonstrate raising the melting point of a gelatine emulsion in his “tropical thermal developer.”

    Walker claims his formula is particularly useful for a busy person who cannot afford the time to wait for development to be completed, and “may remove his simultaneously developed and fixed emulsion, hours or days after he had placed it in the developing tank, with preliminary agitation.”

    Unfortunately, however, Walker’s formula is unlikely to work well with most modern film emulsions. I found it more active than you might expect at around 20C. It worked best with Kodak XT, a slow (Daylight EI 25,) fine-grained motion picture film manufactured between 1964 and 1970. This film was out-of-date when I acquired a 400-foot roll in the mid-1970s, and although it’s probably lost some of its panchromatic sensitivity, it seems to have survived quite a few Australian summers relatively unscathed without refrigeration. I don’t have any of the new slow Efke or Adox films, but they may also be worth trying with this formula. Lith film cleared, but would require a lot of experimentation to achieve pictorial contrast. HP5+ seemed to develop fog faster than it cleared, though it might be usable with curtailed development and re-fixing in a conventional rapid fixer. Re-fixing for permanence is probably advisable anyway, unless you’re willing to undertake the requisite residual silver testing. Like many monobaths, this formula seems slightly prone to sludging, which generally wipes off, or dissolves in fresh rapid fix.

    As Haist explains in Modern Photographic Processing, p. 598, sodium sulfite is a weak solvent for silver chloride, and to a lesser extent silver bromide. I wondered if it might be worth reviving sulfite fixation for alternative processes, e.g. salt or albumen prints. These older silver chloride emulsions might suffer less image regression in a milder fixer; and total processing time and permanence might be improved, with longer fixing times compensated for by significantly reduced washing times and no residual thiosulfates. The disadvantages, however, may outweigh the benefits.

    In the British Journal Photographic Almanac for 1887, p. 80, W. de W. Abney advocates a 20% sodium sulfite two bath fixing system for albumen prints, with only one [presumably full plate] print being fixed in 10 fluid ounces [around 300 ml] for fifteen minutes before being passed into the second bath. The second bath is subsequently cycled to become the first. Abney indicates the solution should be acidic, “if alkaline a little sulphuric acid is dropped in till the solution smells of sulphurous anhydride. It is then gently warmed to expel the gas, and when cooled is used.” He attributes problems “to one of three things – to alkalinity of the sulphite, to the sulphite being old, and through careless keeping, being oxidised to sulphate; or to using the fixing bath for too many prints.”

    Nicol originally advocated ammonia fixation for kallitypes, but use of a dissolved gas proved unreliable, and it was replaced by sodium thiosulfate, although, according to Dick Stevens, Making Kallitypes, p. 203, Namias later advocated replacing the hypo solution with a 15% solution of sodium sulfite for brown prints. Clerc rejected Namias’ suggestion as “more expensive”, presumably compared to a 5% hypo solution with a greater capacity. In addition, the need for additional trays and a more time-consuming processing regime (although perhaps a tray cascade system could be used for fixing, rather than washing), and the need to delay normal room lighting inspection of an Azo-type emulsion, may constitute additional disadvantages.

    Anyway, based on only limited testing involving only a series of single 35mm frames in 100ml in the bottom of a development tank for a few hours, Walker’s monobath will definitely work with at least some older-type films. It seems relatively forgiving of cursory agitation and temperature control, although I found it a bit difficult to obtain reasonable contrast with my outdated XT. Skies tend to block up, and green vegetation seems underexposed. Perhaps it might work better with slightly less metol than 2.5 grams per litre, and even more sulphite. Nevertheless, this must be film processing at its simplest, developing and fixing in a single solution of only two chemicals.

    Philip Jackson

  3. #123
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,027
    Images
    65
    Philip;

    I have difficulty believing that this will work with modern 9% Iodide emulsions. IDK, but this is a stretch. It may take weeks to see browning due to silver retention or problems due to other odd ball reactions. Test,test, test to see if things are right, otherwise you may be mislead. Remember that sulfite is NOT a fixing agent. It only appears as such.

    PE

  4. #124

    Join Date
    Apr 2007
    Shooter
    Large Format
    Posts
    26
    I agree fully with the cautions above - I haven't done the testing and am definitely not advocating a metol-sulfite monobath as 'archival' for any emulsion with any amount of iodide in it whatsoever! It's marginal at best (if indeed it even reaches the line), and you'd best off re-fixing in a conventional fixer if you intend to keep a negative from an experiment with this simple monobath for any length of time. -Philip

  5. #125
    keithwms's Avatar
    Join Date
    Oct 2006
    Location
    Charlottesville, Virginia
    Shooter
    Multi Format
    Posts
    6,079
    Blog Entries
    20
    Images
    129
    Reporting some first results here.... I did my first MM1 dev last night with my co-experimentalist Diwan Bhathal, using some 35mm ilford pan f he rated at 25. The back story is that I drove from drug store to drug store in Bethesda on a Sunday night looking for NaOH, which I had failed to pack in my kit, and they weren't about to give me any. Do I really look like a meth maker? Well maybe I shouldn't have mentioned the phenidone. After I concluded that I'd better call it 'lye' and say I want to make soap, I quickly located some in the drain-clog-removal section of a hardware store and the test was done with success.

    So... <drumroll> ...here are the results.... and yes, we deliberately chose a very contrasty scene....

    MM1 neg, full frame


    D23 neg, full frame


    MM1 neg, zoom


    D23 neg, zoom


    A few comments.... N.b. I had added extra lye to boost contrast, don't ask me why, it seemed like a good idea at the time, but clearly the effect wasn't helpful: the tonal detail is there but would likely be harder to get out of the neg in print, the d23 neg has kinder CI.

    Sharpness/acutance clearly goes to d23, but... hey for contact printing the sharpness of the mm1 would be totally fine. More than acceptable.

    Dev details: I gave the film 7 mins in the mm1. After that it was washed in water, that's it.

    All in all, a very satisfying first attempt at monobath.
    Last edited by keithwms; 02-01-2010 at 05:59 PM. Click to view previous post history.
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]

  6. #126
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,289
    Images
    20
    Great first attempt. Follow Haist's recommendations to reduce contrast, and I bet you get better sharpness as well.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  7. #127
    keithwms's Avatar
    Join Date
    Oct 2006
    Location
    Charlottesville, Virginia
    Shooter
    Multi Format
    Posts
    6,079
    Blog Entries
    20
    Images
    129
    David, did you try the other monobath developers in Haist's book, the sodium thiosulfate (slightly different from fx6a, same ingredients) and mercaptoacetic ones in chp. 4? His acutance plot on pg. 79 looks quite interesting. Looks like the thio gives a 2x increase in acutance, as he defines it. Must be a very substantial edge effect.
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]

  8. #128
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,289
    Images
    20
    The mercapto acid ingredients were harder to obtain, so I was curious about those, but didn't try them, and the thiosulfate formula in ch. 4 didn't seem like too different a starting point from FX6a, since I was tweaking it anyway, so I didn't bother with it. I'd be interested in knowing how the mercaptoacetic acid formula works, if you can get the stuff to make it.

    Where did you find glutaraldehyde for MM1?
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  9. #129
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,027
    Images
    65
    The Formulary sells glutaraldehyde David.

    PE

  10. #130
    keithwms's Avatar
    Join Date
    Oct 2006
    Location
    Charlottesville, Virginia
    Shooter
    Multi Format
    Posts
    6,079
    Blog Entries
    20
    Images
    129
    Yep I got everything including the gluta from the formulary. Well, the lye I got from the hardware store.... I might switch to lab grade lye next time though. It looked pure but one never knows.

    Formulary! Why don't you have a general monobath kit, including all the ingredients for the common ones? Took me a while to put it all together.

    I can get the mercapto stuff easily, those compounds turn out to be fairly common in my line of research. Let me suggest looking at pierce bio or sigma. I can schniffel around and see what I find in the lab.
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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