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  1. #51

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    Quote Originally Posted by Michael R 1974 View Post
    Hi Mark - regarding the most recent scans, I'm having a hard time finding any consistent differences one way or the other (essentially the same experience I had with the first scans). And I know your curves are essentially identical. My two cents: given the magnification, for practical purposes any differences in apparent graininess or sharpness between the concentrate and XTOL with this film are trivial.
    Michael, thanks for responding! Your observations agree with mine, but I don't trust mine because I'm biased. At least with HP5+ and TMY2, this concentrate is achieving the goal of matching XTOL's grain, sharpness, curves and dev-times. But as a non-aqueous concentrate, it should last much longer. I'm encouraged, and will run more tests with it.

    @Kirk Keyes - Well actually (swallowing hard), I do keep this in my food-refrigerator. Unless there are small children in a household, well-marked bottles of chemicals will never be accidentally ingested. And even if they were ingested, these chemicals are nearly non-toxic, so little harm would result. Some other chemicals, on the other hand...

    @relayer - I like your ideas of potassium sulfite and reducing sulfite. In fact, I've tried both. This concentrate is intended to act exactly like XTOL, but I want to explore your ideas more to make developers that are different from XTOL. One reason I avoided potassium sulfite is I thought it was difficult to obtain; can you buy it in Ukraine?

    Mark Overton

  2. #52

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    Quote Originally Posted by albada View Post
    @relayer - I like your ideas of potassium sulfite and reducing sulfite. In fact, I've tried both. This concentrate is intended to act exactly like XTOL, but I want to explore your ideas more to make developers that are different from XTOL. One reason I avoided potassium sulfite is I thought it was difficult to obtain; can you buy it in Ukraine?
    yes, I can buy it in Ukraine, but price is high. but I have other problem - sodium metaborate (kodalk) is very problematic to purchase in small quantity.
    try 1st to reduce amount of sodium sulfite. may be this increase sharpness without dramatic increasing grain size.
    here is my "clone" of XTOL:

    RD-117 developer
    Salicilyc acid 1g
    Sodium sulfite 33g
    Ascorbic acid 4.15g
    Borax 8,5g
    Phenidone 0.2g
    Water 1l
    pH 8.2

    starting dev.time same as for D-76

  3. #53
    kb3lms's Avatar
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    Mark,

    I don't see any differences between the XTOL and your concentrate. XTOL is my favorite developer and I am planning to try your concentrate since the concentrate would match up better with the volume of film I get to process. Really great stuff! Keep going!

    -- Jason
    All this has happened before, and all this will happen again.

  4. #54

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    Quote Originally Posted by kb3lms View Post
    Mark, I don't see any differences between the XTOL and your concentrate. XTOL is my favorite developer and I am planning to try your concentrate since the concentrate would match up better with the volume of film I get to process. Really great stuff! Keep going!
    -- Jason
    Jason, thanks for the encouragement! I designed this concentrate for hobbyist-shooters like us who can't use even half of five litres of XTOL in six months.

    A few days ago, I said that if Dimezone or Phenidone is mixed in last (instead of first), it starts a reaction that produces viscous cloudy liquid and scale on the beaker. Here's a photo of the scale. Everywhere the stirring rod rubbed the beaker, it started a reaction producing a line of scale.

    Click image for larger version. 

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    I suspect the cloudiness and this scale are the same catalytic reaction. Have any of the chemists here seen anything like this?

    Mark Overton

  5. #55
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    These are crystals formed by the stirring rod scratching a saturated mixture which then begins to form at the site of the scratch. It is well known to Organic Chemists that they must scratch some mixtures to begin precipitation or crystallization. As for why this forms in one case and not another, it may be due to a salt being formed in one that is not in the other.

    BTW, very nice work on the concentrate. The results look great.

    PE

  6. #56
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    Relayer: You can make Kodalk yourself using Mike Wilde's recipe (comes with great explanation! ). The recipe you posted contains salicylic acid which is a mild iron chelate, Ryuji Suzuki uses it in DS-10 to prevent iron catalyzed decomposition of ascorbate.

    Mark: Two things.
    • If I compare Xtol to DS-10 in terms of usability, the biggest difference is that Xtol can develop slow films like PanF and TMAX, while DS-10 instructions recommend specifically against using DS-10 with these slow fine grained films. It would be very interesting how MOtol (your version of Xtol) copes with these films. Of course, there are more suitable devs for these slow films, but if one develops a few rolls a year (which is where your dev really shines! ) it may be nice to know that this dev also works for the rare roll of PanF+.
    • While deionized water is easy to get, it would be very nice if your dev could use tap water. Do you think you could add some sequestrants to your recipe? You don't have to worry much about iron with your concentrate, but calcium and magnesium should be taken care of. Calgon and Na2-EDTA should be easy to get, but they will change the pH and this must be accounted for.
    Trying to be the best of whatever I am, even if what I am is no good.

  7. #57

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    The choice of sequestering agents that can be used in an ascorbate developer is very limited. EDTA, for example, will actually promote the oxidation of the ascorbate ion. This has been menthioned many times and by Ryuji himself.
    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

  8. #58
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    Quote Originally Posted by Gerald C Koch View Post
    The choice of sequestering agents that can be used in an ascorbate developer is very limited. EDTA, for example, will actually promote the oxidation of the ascorbate ion. This has been menthioned many times and by Ryuji himself.
    Oxidation of ascorbate should be a non issue if you mix fresh from concentrate and use right away. I am aware of Ryuji's statements but unlike Mark's recipe Ryuji's published recipes are not concentrates in PG. The sequestrant I suggested should at least take care of Ca2+ and Mg2+, therefore I suggested Na2-EDTA and Calgon.
    Trying to be the best of whatever I am, even if what I am is no good.

  9. #59
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    Just a note: if you source all the chemicals from Photographer's Formulary, each batch costs $3.71 without shipping. The most expensive ingredient is $1.03 of Propylene Glycol. This is assuming you only buy quantities <$10, except the Sodium Sulfite which is $17 for 5 lbs.
    I take donations for beer and film​.

  10. #60

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    Acros-100 results

    Two rolls of Acros-100 developed in XTOL and the concentrate look identical. The details are below. My testing so far shows that the concentrate behaves like XTOL for Kodak, Ilford and Fuji emulsions; for T-grain and traditional grain; and for 100- and 400-speed.

    The concentrate had been kept in the refrigerator for a week, in case anyone cares. Here's a graph from a Stouffer wedge on my light-table, showing the density-curves for XTOL and the concentrate:

    Click image for larger version. 

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    And here are full-resolution (2900 dpi) crops of neg-scans of the same frame-numbers from each of the two rolls:

    Frame 24: Xtol: Click image for larger version. 

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    Frame 25: Xtol: Click image for larger version. 

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    Frame 26: Xtol: Click image for larger version. 

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    The curves, grain and sharpness are all essentially identical to my eye.

    @Rudeofus: Ryuji said that APX-100 and Pan-F worked poorly in DS-10. Pan-F is still in production, so I'll order some rolls and try it. Thanks for posting that idea. BTW, I thought Ryuji speculated that the failures were caused by DS-10's low pH of 8.0. I'm running at 8.3, which is a tad above XTOL and the same as D-76, so at least the concentrate won't have problems due to low pH. Nonetheless, I'm going to test Pan-F.

    What problems do dissolved minerals in water cause? A search of apug.org shows some calcium specks on negatives if it precipitated out of solution. Also, folks say that carbonate causes calcium to precipitate, which my concentrate lacks, so hopefully that won't be a problem. My tap water is hard, so I'll try it on test-strips tomorrow.

    One problem with sequestrants is that many are inorganic salts, and thus won't dissolve in PG. Citric acid is an exception, but it's a rather strong acid that I'd need to compensate for somehow.

    @choppastyle: From a cost point of view, a low-volume shooter will save a little money using the concentrate. But my main motivations are (1) I hate to discard litres of expired developer every 6 months, (2) after 4 months, I lose confidence in XTOL and wonder if sudden death will hit me, and the concentrate will give me confidence for much longer, and (3) a little sulfite precipitates out of Xtol's solution, which looks like shredded tissue floating in it, and a poster said those are "hot" and can cause overdeveloped spots on negs. I've had that shredded tissue issue in both of my batches of Xtol, and solved it by vigorously shaking the bottle when warmed. The concentrate won't have that problem as it's mixed shortly before use.

    I'll do more tests, but the big test now will be longevity, and that takes time.

    Mark Overton

    EDIT: For the Acros rolls: Xtol leader density was 3.09, and concentrate leader was 3.10.
    Last edited by albada; 07-21-2012 at 12:48 AM. Click to view previous post history.



 

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