Dektol won't dissolve?

Discussion in 'B&W: Film, Paper, Chemistry' started by Bobby Ironsights, Apr 1, 2008.

  1. Bobby Ironsights

    Bobby Ironsights Member

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    That's a complaint I've heard a bunch, and it's annoying as frick alright.

    I buy my chemicals in bulk pure and save money and the annoyance of measuring is offset by the ease of mixing, but it also makes the chems dissolve faster.

    The problem is the METOL, the metol is the chemical that doesn't like to dissolve in water that already has any other dissolved salts in it. Unfortunately the metol is one of the developing agents so you HAVE to get it dissolved. It dissolves easily by itself so when you make it at home you just dissolve it first, then add the other chemicals afterwards.

    It's really cheap to make dektol my way. I think 500 grams of metol cost me something like eight dollars? It's hard to remember, as you only use a few grams of metol per liter of paper developer so you can mix hundred of liters per canister of metol.

    Now that I've stopped using the orange bags and gone to mix-it-myself powders, I ignore the "capacity" and "shelf life" of my chemicals (almost all common powdered pure photochemicals last decades) and just mix everything new, every two weeks. I figured out that it's just so cheap, it's not worth my having milky prints every once and awhile, figure out that my Dektol is too old, and then having to mix more up, and try to get it to temperature or more often just pack everything up(I use a bathroom darkroom), or worse yet, end up with nasty negatives.

    It's improved my consistency greatly, and now that I'm good with my kitchen scale, and workflow it only takes about forty minutes to make, measure, and mix a liter of hardening fixer for film, two one liter bottles of non-hardening fixer for prints (makes toning much easier), a liter of D76, a liter of dektol and a liter of stop bath. All of those chemicals together probably cost less than four dollars and half that is the distilled water I use for everything.

    I might have to start mixing more often in the summer, but while I'm busy with school that amount does me just fine.
     
  2. MartinL

    MartinL Member

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    I am getting ready to start mixing my own as well. More out of neccesity though. It has gotten to the point here where I have to drive 30 or 40 minutes to pay high prices or order online and and pay UPS's ransom-like shipping charges. I am thinking just like you though. I have to say I have never had a problem with the Dektol dissolving though.
     
  3. Konical

    Konical Subscriber

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    Good Morning, Bobby,

    Strange about the Dektol. In a previous location, I had some difficulty getting D-76 completely dissolved, but Dektol was absolutely no problem. My own highly unscientific conclusion, based on subsequent experience, is that the water characteristics must have played a part in the difficulty with D-76. Dektol, in three different communities with three separate water supplies, has always been a snap to mix.

    Konical
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    That is why I designed Liquidol! Same as Dektol but higher capacity and tray life.

    PE
     
  5. Paul Verizzo

    Paul Verizzo Member

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    Metol should dissolve just fine. Is your water hot enough? Kodak says 125 degrees? That's hotter than most home hot water heaters can deliver, especially after sitting a few minutes.

    At that temperature the infamous hard to dissolve phenidone does so rapidly. Ditto benzotriazole.

    Eight dollars for a pound of Metol is either a function of long ago and your memory or a hell of a deal. It runs $30 a pound, generally, nowadays.

    As a tangent, I've just mixed up some Ilford ID-62 as a phenidone replacement for Dektol/D-72. I'm thinking it's in the line of Ethol LPD which has a great reputation for, um, Lasting. I doubled the sulfite based on the experience of another APUG poster. Hopefully, I'll have a chance to test drive it within the week.
     
  6. Keith Tapscott.

    Keith Tapscott. Member

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    Kodak already have a liquid version of Dektol which is diluted 1+9 instead of the 1+2 dilution recommended for powder form version of Dektol.
     
  7. CBG

    CBG Member

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    There's a reason the chemicals are listed in the order they are in the printed formulas. They should be mixed in that order, and will dissolve in that sequence. Metol is listed first in most formulations.

    C
     
  8. jnanian

    jnanian Advertiser Advertiser

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    bobby,

    add a pinch of sodium sulfite
    before you put elon/ metol in,
    it will change the water's ph
    and allow the metol to dissolve.



    john
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    As I said, my version has 2x the capacity or shelf life!

    PE
     
  10. KenM

    KenM Member

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    Formula?
     
  11. Photo Engineer

    Photo Engineer Subscriber

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    Photographers Formulary has it.

    PE
     
  12. Jim Noel

    Jim Noel Member

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    John is correct. This works and works very well!
     
  13. Photo Engineer

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    Adding sulfte will prevent oxidation from taking place, and that is the reason for the pinch of sulfite. If you add sulfite to a package mix, you may have too much sulfite!

    Metol is an alkaline organic compound that is often sold as the sulfate salt. It is difficult to dissolve in alkali unless you make the acid salt which is the way Dektol is formulated.

    So, unless you scratch mix, don't add the sulfite.

    PE
     
  14. Keith Tapscott.

    Keith Tapscott. Member

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    Which brings me back to the subject of stabilising agents used in developers compounded into a single-powder. I read somewhere that Kodak `Elon` is a particular very pure form of Metol and less likely to cause `Metol poisoning` than some less pure forms. How does this acid salt differ from regular Metol? I have read some of the patents for single-powder developers dating from mid 1940`s to early 1950`s, although I still don`t understand the function of Boric anhydride (Di-boron Trioxide) as a stabilising agent. Also, is the specially treated `Lithium hydroxide` used to boost the pH back to the desired level due to the inclusion of Boric anhydride?:confused:
     
  15. Photo Engineer

    Photo Engineer Subscriber

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    I think lithium salts are used for the psycotherapy of photographers.

    Basically the developer is milled into small particles under nitrogen. The chemicals are protected by a variety of antioxidants to keep the developing agents and the sulfite from going bad. The alkali is in a separate particle from the developing agents and antioxidants in some mixtures, and so you see different types of granules in the mix. The hot water helps break down the granules.

    Early on, Metol had impurities, but I'm not sure of what all went on. Elon is or was, the purified salt of Metol made with sulfuric acid. It may be that Metol was offered as a sulfate as well, but I have not read this part of the history for years.

    In fact, the entire process for this has begun to fade badly. It has never really been documented anywhere outside of Kodak AFAIK with only minor references.

    PE
     
  16. vet173

    vet173 Member

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    Sorry for the drift but I have always wanted to ask PE what are the two black specs that I have found over and over in Dektol packages? Is there some guy on the line counting them as added?
     
  17. Keith Tapscott.

    Keith Tapscott. Member

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    The patents that I have read are rather dated, although it is a subject that fascinates me. With raw chemicals, it is recommended that Metol is dissolved before the Sulphite which is where the inclusion of the Elon mixed with the rest of the components in one powder interest me. I am not quite sure of the Boric anhydride though after reading the section of Borate Alkali`s on page 244 of Grant Haist`s book.
    MSDS for Kodak developers I found here: http://www.kodak.com/eknec/PageQuer...locale=en_GB&pq-locale=en_GB&_requestid=11047

    Ethol UFG, LPD and Acufine are also single mix developers, so not exclusive to Kodak.
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    I have no idea what you are talking about. Maybe they are 'getters' for anything that can oxidize the developer. IDK.

    I could give you the name and address of the head of Powders and Solutions at Kodak, but he left and entered the ministry. :D

    PE
     
  19. Photo Engineer

    Photo Engineer Subscriber

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    This is gonna be hard to do, but here goes....

    Hydroquinone is HO-Phenyl-OH
    Metol is CH3-NH-Phenyl-OH
    Elon used in Dektol is (CH3-NH-Phenyl-OH)^+2 and H2SO4. There are 2 metols for every sulfuric acid and so you have (CH3-NH2^+ -Phenyl-OH)2 and SO4^= (the ^ denotes superscripting)

    This means that Metol is both an acid and a base, but the base form is very subject to reaction with air, and so it is made into a salt of sulfuric acid where two Metols react with one sulfuric acid. This is the "Bis" in the MSDS. It means two of them are associated with each sulfuric acid.

    Now, when you hit base.... You get salts of these as follows:

    HQ is Na-O-Phenyl-O-Na where phenyl has two negative charges on the HQ oxygens.

    Elon is now CH3-NH-Phenyl-O-Na with one negative charge on the oxygen. The sodium ions are positive.

    Has this confused you enough yet? We still have oxidation products to go and sulfonation of the HQ. But I think you see that there is a lot involved in this simple mixture that must be protected from air and water in the package until it gets to you.

    PE
     
  20. Keith Tapscott.

    Keith Tapscott. Member

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    Confused and intrigued, thanks.:smile:
     
  21. vet173

    vet173 Member

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    Thanks, I was being facetious. But there always seems to be a couple of black specs.