Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,854   Posts: 1,582,930   Online: 989
      
Page 7 of 58 FirstFirst 123456789101112131757 ... LastLast
Results 61 to 70 of 576
  1. #61

    Join Date
    Apr 2008
    Location
    Escondido, California, USA
    Shooter
    35mm RF
    Posts
    674
    A second experiment done this afternoon makes me suspect that the Instant Mytol formula is incorrect. I created a small 50 ml working solution (not concentrate) with the correct proportions of all ingredients except that I omitted Phenidone. I simultaneously dipped pH test-strips into this test-solution and fresh XTOL, and compared their colors with each other and with the color-charts. I did this with two brands of pH-strips. Both showed XTOL at 8.0 and the test-solution at 8.7. These numbers are approximate, but the conclusion is clear: The pH of Instant Mytol is too high.

    I'll reduce the TEA in Instant Mytol to get the pH correct (matching colors with XTOL). Or maybe I'll skip this stepping-stone and move onto modifying this formula to mimic DS-10. Let's see, DS-10, that was the goal of all this, wasn't it?

    Jerry, like you, I don't shoot that much, maybe a roll a month. And some of that is C-41. So the desire is for a developer that gives XTOL-quality but that keeps a long time, and is tolerably convenient. Mixing two things such as concentrate and sulfite is fine, but having to mix everything from scratch just to dev one roll is too much effort.

    PE: Thanks for the warning about Ammonium bromide and fog. I've entered that into my file of chemistry notes. You have an enormous amount of knowledge of tidbits like this, not to mention principles of operation for all kinds of processes. Have you considering putting all this into a book? If so, sign me up to buy a copy!

    Mark Overton

  2. #62
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,535
    Images
    65
    Mark;

    Right now I am in the final stages of writing the Photographic Emulsion Making and Coating book. Bill Troop and I have discussed writing what you say and there are some interviews on tape with Scott Sheppard on this topic somewhere. Unfortunately, the book you envision will take several years to produce and cost a bit. Also we need to get rights to portions of Anchell and Troop to kick start the project.

    PE

  3. #63

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    4,131
    Ron I would say give it a try. Since there would be much more ammonium sulfite and hence more ammonia I would do it outside. I sometimes miss having a hood. Jerry
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  4. #64

    Join Date
    Apr 2008
    Location
    Escondido, California, USA
    Shooter
    35mm RF
    Posts
    674
    So far, my experiments show that about 6.8 ml/L is the correct amount of TEA to add to Instant Mytol to hit the target pH of 8.2, instead of the 13.4 ml/L given in the formula.

    Question 1: What alkalis will dissolve in propylene glycol?
    Obviously TEA will, as will borax. Sodium carbonate contains carbon, so perhaps it'll dissolve also? I don't have much hope for sodium metaborate, but I'll have to check whether it's considered organic. Other alkalis? I'd like to experiment with the effects of alkalis on image-quality. The grain from TEA looks rougher than I like.

    Question 2: What halide-solvents will dissolve in propylene glycol?
    Sodium chloride or ammonium chloride? I suspect PPD will, but its toxicity concerns me, and it's a developer also.
    It would be convenient to not have to dissolve sodium sulfite separately from the concentrate.

    Thanks,

    Mark Overton

  5. #65

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    4,131
    Most inorganic compounds will not dissove in glycols. You are really restricted to using an amine TEA, DEA, or MEA and a few others. Kodak uses sulfur dioxide adduct as a halide solvent and preservstive in HC-110.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  6. #66

    Join Date
    Jun 2003
    Shooter
    Large Format
    Posts
    16,882
    Quote Originally Posted by albada View Post
    Thanks for the suggestion. Coincidentally, the TEA arrived in the mail today, so you can guess what I'll be doing this weekend.
    A few postings in apug.org have noted that PC-TEA is a little grainier than XTOL, probably due to having no solvent in the soup. Adding Sodium Sulfite creates Jordan's "Instant Mytol", described here: http://www.apug.org/forums/forum223/...ant-mytol.html
    So I'm thinking of trying some of that Instant Mytol.

    Mark Overton
    hi mark

    why don't you contact ryuji himself ( he has a website and is accessible )
    rather than ask people who may or may not have any idea of what his changes might have been ?

    good luck !

  7. #67

    Join Date
    Apr 2008
    Location
    Escondido, California, USA
    Shooter
    35mm RF
    Posts
    674
    Gerry: I was afraid of that. PG is a good carrier (I guess that's a good word for it) because oxidation isn't a problem, but few things will dissolve in it.

    Jnanian: That's a good idea! It hadn't occurred to me to contact Ryuji. It's winter, so his freelance photo business is probably slow now, and maybe he'll have time to talk about his work. BTW, did he simply lose interest in film? It seems he hasn't posted in a few years now.

    Anyway, I'll be shooting a roll of Tri-X today at a company-luncheon. The camera will be a Minolta V2. Gotta love those classic cameras.

    Mark Overton

  8. #68

    Join Date
    Jun 2003
    Shooter
    Large Format
    Posts
    16,882
    Quote Originally Posted by albada View Post
    Gerry: I was afraid of that. PG is a good carrier (I guess that's a good word for it) because oxidation isn't a problem, but few things will dissolve in it.

    Jnanian: That's a good idea! It hadn't occurred to me to contact Ryuji. It's winter, so his freelance photo business is probably slow now, and maybe he'll have time to talk about his work. BTW, did he simply lose interest in film? It seems he hasn't posted in a few years now.

    Anyway, I'll be shooting a roll of Tri-X today at a company-luncheon. The camera will be a Minolta V2. Gotta love those classic cameras.

    Mark Overton
    hi mark

    i am not sure if he lost interest in film or traditional photography: i doubt it.
    he not only was involved with creating photochemistry, but he also
    was very involved in making photo emulsions.

    you can probably look up his threads / posts when he was here
    to see what was going on " politically " when he was here ...

    good luck !
    john

  9. #69

    Join Date
    Jan 2005
    Location
    Boston, MA
    Shooter
    Multi Format
    Posts
    1,416
    All right Mark, your email got me curious and googled and found this. It's kinda surprising I remembered the login u and pw.

    First, I recommend you to get a better way to measure pH than test strips. You'll notice that pH difference of 0.2 would make a significant difference in the development time required to attain a target contrast index.

    Triethanolamine is a good alkaline agent in fine grain developers. If you are making an accutance developer or more rapid action developer, you can mix diethanolamine as well. Some of the derivatives of TEA and DEA are also good alkaline agents (some names were given in my old posts - please find them). You can get a range of buffering systems with them. But, if you are a casual darkroom hobbyist, don't go there.

    Borax is a really good buffer for pH 9 range, but not really for 8 or 10. It's easy to use, and cheap, but that's about it.

    Small quantity of ammonium salt would probably do little harm at pH of 8.2. But I'd rather not use them, unless you know what it affects and carefully control for it. I recall trying using ammonia in small quantities, but I vaguely recall the results varied a lot depending on the film. That was actually somewhat expected. Also, I'd definitely not use ammonium salt in developers of pH any higher than that.

    I actually have an improved version of fine grain developer as well as high accutance developer, but never commercialized.

    Regarding the silver halide complexing agent for fine grain effects, I also played around with a few pyrimidine derivatives. Some are interesting because they are also a very mild developing agent when used alone. But after all, sulfite was easier to use and a lot cheaper.

    Another thing I never posted before is that I have a developer stabilizing additive. This actually improves the shelf life and tray life of the developers. It was used in print developers that had silvergrain label and sold in F-style jugs but not any other bottle shape or label. This thing actually works well in film dev as well, but the additive looks brown color and a lot of users would get confused with the color of stale developers. So that was another concern for me and I didn't want to go ahead without a colorless stabilizer additive. But I was using it for routine processing in my lab.

    Another challenge is that if you try to make a highly concentrated film developer (as I was doing) you'll sooner or later face a problem with phase separation. Some of the compounds in the concentrated developers do not mix with water rich of inorganic salts. So, you'll get sulfite-rich water phase and "oily" look phase containing amines, Dimezone S, etc. There are some solvents you can use to blend them, but they're not particularly safe. Certainly not the kind of stuff I'd put in if I were to sell the product as low toxicity. Well, that was a part of the reasons why I was looking for something to partially replace sulfite with.

    Alright, I think I shouldn't write much more frmo memory - any more would risk being incorrect.

  10. #70

    Join Date
    Jan 2005
    Location
    Boston, MA
    Shooter
    Multi Format
    Posts
    1,416
    Quote Originally Posted by Gerald C Koch View Post
    Saying that a formula has too many ingredients is like saying that Mozart's music has too many notes.
    Good quotable statement.



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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