Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,288   Posts: 1,535,344   Online: 817
      
Page 4 of 11 FirstFirst 12345678910 ... LastLast
Results 31 to 40 of 104
  1. #31

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    Quote Originally Posted by gainer
    The problem that I had with trying to leave a litle precipitate was that the reaction upon adding hydroxide solution was slow. The visual feedback was delayed enough that I added too much hydroxide.
    The formula which I use says to first add x milliliters of the hydroxide solution. Then it says to add the hydroxide slowly until there is a sudden darkening of the solution. At this point the hydroxide should be added very slowly until most of the remaining precipitate dissolves but a small amount is left. Using this method the bulk of the hydroxide can be added all at once.

    Sodium or potassium hydroxide and potassium metabisulfite are all of variable purity and may vary by several percent from batch to batch. This necessitates "titrating" the bisulfite/pap mixture with the hydroxide solution. I have made many batchs of "Rodinal" and have never had much difficulty. Should one overrun the endpoint it is easy to add a small amount of metabisulfite to bring back some precipitate.

  2. #32
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    Quote Originally Posted by Jurgen
    I don't want to be critical but I did a few calculations on the rodinal formula in the darkroom cookbook. After converting the HCl salt to base and assuming all 400ml of KOH is used it appears to be about 0.5 molar in para aminophenol, about 55 grams. This would require about 20 grams of NaOH. Not sure about the sulfite.

    Also the pH of your formula at 1:25 would be about 12, at 1:50 about 11.6.

    Jurgen
    Criticism is good. I had to do enough of it and endure enough of it while working at NASA to know the value of it.

    I don't think the amount of sulfite is critical, as long as it is not in the bisulfite form. Then, of course, it would have a considerable effect on the amount of hydroxide required.

    I ordered a big bunch of p-aminophenol to play with. I'm thinking another wat to go about this variation in purity would be to use the calculated amount of hydroxide and see if there remains any precipitate. If so, leave it alone. If no, add a little p-aminophenol.

    I'm quite happy with the results I got after I reduced the pH with bisulfite in accord with your previous helpful criticism. Of course, this adds a little to the net sulfite content, but this is very small in the working solutions even if it were double. I could experiment with that as well.

    I found that p-aminophenol is on the list of hazardous materials, which is probably the reason some do not want to ship it. They should be able to ship it by UPS ground, but that leaves out overseas I guess.
    Gadget Gainer

  3. #33
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    No new results, but some new thinking on my part. I have seen several recipes for Rodinal, as have we all, and have concluded that the ones that start with 100 g p-aminophenol.HCL are fro1.5 or 2 liters of stock, as they start with one liter before adding the hydroxide solution. The one recipe I saw with 50 g started with 500 ml, added hydroxide to almost dissolve the solids, then brought the solution up to 1 liter. 50 grams of the hydrochloride contains about 37.5 grams of the p-aminophenol, which is about 0.344 gmw. If I start with the base p-aminophenol, I should only need 0.344 gmw of a hydroxide, which is about 13.7 grams of sodium hydroxide. The sulfite is a little trickier to calculate, but 150 grams of potassium metabisulfite in water = 0.675 gmw which can be replaced by 1.349 gmw of potassium bisulfite, which after all is done amounts to 1.349 gmw of any soluble sulfite. That would be 170 grams of sodium sulfite in the liter of concentrate. I conclude that a solution of 37.5 grams of p-aminophenol, 170 grams of sodium sulfite and 13.7 grams of sodium hydroxide should make a liter of a sodium Rodinal Expedient. We will see.
    Gadget Gainer

  4. #34

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    Not only are there many recipes for Rodinal like developers there are several which use Metol and hydroquinone. Both these developing agents form phenolates with hydroxides just like paraminophenol. The following recipe which appeared in the Dignan Newletter is based on one from 1917 when Rodinal was hard to obtain because of WWI. The original formula was sold commercially in 1917 and was published by the author Paul L. Anderson in his book The Technique of Pictorial Photography", J. B. Lippincott, 1939.

    Kalogen

    Distilled water (50°C) .................. 750 ml
    Metol ....................................... 13.5 g
    Sodium sulfite (anhy) ................... 180 g
    Hydroquinone ............................ 53.0 g
    Sodium hydroxide ........................ 35.0 g
    Potassium bromide ....................... 5.0 g
    Benzotriazole, 1% ....................... 80.0 ml
    Distilled water to make ................. 1.0 l

    Dissolve the ingredients in order. When the hydroquinone is added a heavy white precipitate will form which will dissolve when the hydroxide is added.

    For films dilute 1+49, average development time is 5 minutes at 20C. For papers dilute 1+11 to 1+14. Results are very similar to Dektol.

    This developer has a very long shelf life of at least 2 years in fully filled bottles.

    Like Rodinal this is not a fine grain film developer but the grain is crisp and pleasing.

  5. #35
    df cardwell's Avatar
    Join Date
    Jul 2005
    Location
    Dearborn,Michigan & Cape Breton Island
    Shooter
    Multi Format
    Posts
    3,342
    Images
    8
    [COLOR=DarkRed]Patrick, and all

    Going through a box of books today... an early 1920's ( although undated ) softcover book entitled, "AGFA Photo-Handbook" by Dr. M. Andresen.

    Like this so far ?

    Besides having all kinds of interesting things to do WITH Rodinal, there are two formulae in the chapter entitled AGFA Developer Chemicals for "AGFA Paramidophenol (hydrochloride)".[/COLOR]

    Page 262

    "AGFA Paramidophenol (hydrochloride) in combination with caustic alkalies produces a rapid developer, whilst with potass. carbonate, or soda carbonate it forms a very slow and clean-working developer".

    FORMULA 20: Two-solution
    A. Paramidophenol hydrochloride 20 grms. 175 grs.
    Water 1000 c.c.s. 20 ozs

    B. Soda sulphite, cryst. 120 gms. 525 grs
    Potass. Carb 120 gms. 525 grs
    Water 2000 c.c.s. 20 ozs.

    [COLOR=DarkRed]NOTE: this is not a typo by me, but I wonder about Agfa's typesetter ! [/COLOR]

    For use, mix 1 part of Solution A with 2 parts of Solution B. The above developer is slow and clean working.

    And,

    Formula 21: Concentrated single solution.

    Dissolve:
    Potass metabisulphite 30 gms 1 oz
    in
    Water 100 c.c.s 3 1/2 ozs
    and then add:
    Paramidophenol hydrochloride 10 gms. 160 grs.

    To the solution thus prepared add slowly, stirring all the time, concentrated caustic lye until the precipitate which forms at first is just redissolved. Keep this solution in well closed bottles and mix with 10 to 30parts of water.

    The above is a very rapid developer.



    [COLOR=DarkRed]Again, there is no date, and I ascribe it as '20s based on the outfits worn by the people in the illustrations. More accurate dating could be done by examing the details of flashpowder packaging, and so on.

    That's it ! Have fun.


    Isn't this more fun than digital ???[/COLOR]
    "One of the painful things about our time is that those who feel certainty are stupid,
    and those with any imagination and understanding are filled with doubt and indecision"

    -Bertrand Russell

  6. #36

    Join Date
    May 2004
    Location
    uk
    Posts
    291
    Images
    10

    spectrum 1

    Found this, never used it though.
    Attached Files

  7. #37

    Join Date
    Apr 2004
    Location
    Louisiana, USA
    Shooter
    Multi Format
    Posts
    1,325
    Not being of the chemical-concocting type, I kind of lost track of this thread with all the formulas involved. Somebody might have mentioned it and I missed it, but Photographer's Formulary website says they will be introducing an already mixed, liquid form of their Rodinal substitute shortly. The mix-it-yourself kits have been discontinued.

  8. #38

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    Quote Originally Posted by Lee Shively
    Not being of the chemical-concocting type, I kind of lost track of this thread with all the formulas involved. Somebody might have mentioned it and I missed it, but Photographer's Formulary website says they will be introducing an already mixed, liquid form of their Rodinal substitute shortly. The mix-it-yourself kits have been discontinued.
    I wonder what they will charge. I have always found that their kits are overpriced for what you get.

  9. #39

    Join Date
    Sep 2004
    Location
    Netherlands
    Shooter
    Medium Format
    Posts
    1,336
    We have enough original Agfa Photo Rodinal in our supply chain. We can offer 10% discount on the second bottle.
    All European APUG members will have no problem till at least next year.

    best regards,

    Robert

  10. #40
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    I have found that the following recipe gives the results of Rodinal with no fuss in the making.

    Start with 700 ml water at room temperature.
    Add 170 grams of anhydrous sodium sulfite, 14 grams sodium hydroxide, and stir till dissolved. Warming it a little won't hurt. Add 40 grams p-aminophenol (not the hydrochloride). It will not all dissolve. Add water to make 1 liter. When you transfer from the mixing vesel to storage, do not filter out the sediment. Use it like AGFA Rodinal.
    Gadget Gainer

Page 4 of 11 FirstFirst 12345678910 ... LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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