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Article: Borax Project

  1. #1
    gainer's Avatar
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    Borax Project

    My Borax Project
    Borax is useful in many ways. Some of us worry about the purity of the commonly and cheaply available 20 Mule Team Borax. There is another concern in cases where accuracy of weight is important. Borax has 2 possible states of hydration, decahydrate and pentahydrate. If a 100 gram sample of pure borax has pentahydrate and decahydrate mixed, the assay will show a greater weight than 100 grams. If 5 grams of a 100 gram sample are the pentahydrate and the rest the decahydrate, no matter how purely the saple is composed only of sodium tetraborate and water of hydration, the assay will show 101.5 grams of the decahydrate. There is no way you can tell at time of collecting a sample from a large batch of pure mixture how much of each hydrate you are getting.
    A common solution to both problems is literally a solution. A saturated solution of borax at a given temperature contains a known weight of borax expressed as the decahydrate, whether the solid used to make the solution was penta- or decahydrate. If the solution was made saturated and separated from the solid at a low temperature, it will have a constant weight of borax per unit weight of solution at any (reasonable) higher temperature. The weight per unit volume will stay constant enough for most uses.
    A simple way to purify a large quantity of borax at the expense of a smaller amount is to make a concentrated solution in boiling water, allow it to crystallize at a temperature below that desirable for keeping, and decant the clear liquid and discard it or use it for cleaning. The soluble impurities in the original borax are presumed to be uniformly distributed in the liquid, so that if, say, 90% of the liquid is removable by decantation and/or fitering, the remaining impurities will be reduced by 90%.
    656 grams of borax decahydrate are soluble in a liter of solution at 100 C. If the temperature is reduced to, say, 15 C, there will remain only 37.9 gram in the discarded solution. The remaining 618 grams of borax has been cleansed of about 90% of its original soluble impurities and is sufficient to make 16 liters of borax solution.
    When I first proposed this approach it was considered by certain of our resident chemists to be a complicated alternative to paying the money for analytical reagent grade of borax and weighing it to the milligram, even though it is well known among other chemists and for the same reason I stated above that such a degree of precision is not warranted by the uncertainty of the state of hydration of borax. Then, to top it off, I had a senior moment and recommended the use of 10 times more of my borax solution than was proper for D-76. That was seen as proof that I knew not whereof I spoke. Furthermore I made the assertion that 10 times too much borax was not as bad as it might seem. In the process of defending my assertion, I found a variation of D-76 that I may (or may not) call "serendipitol". Serendipity is exemplified by the fellow who accidentally walked barefoot through a certain kind of animal excrement and discovered it to be an excellent cure of athlete's foot. I seem to remember that the animal was of the male bovine type.
    I made 3 liters of D-76, two with 10 times the prescribed amount of borax in the form of 425 ml of a 4.71% solution. To one of these were added 20 grams of boric acid crystals. The third liter was made as old-fashioned D-76, using 42.5 ml of the 4.71% borax solution. The rule of this game was to pretend I didn't know about the extra borax and treat it the same as store-bought. I shot 36 exposures of HP5+, bracketing plus and minus 1/2 stop. Any consecutive 4 frames had all three exposures. As it turned out, the nominal exposure was quite good in all three cases.
    I have three cases to show. Each one shows a low resolution scan of an 8x10 print to show its chiaroscuro and a high resolution scan of a portion of that print to show resolution and granularity. The one labeled "D-76" is Metol, 2 grams, hydroquinone,5 grams, 42.5 ml of 4.7 % purified borax solution, and demineralized water to make 1 liter. "D-76 B+" is Gadget's mistake with 425 ml of the borax solution. As cure of the resulting high contrast, I took a cue from more recent D-76 and added 20 grams of boric acid crystals per liter of the mistake and called it "D-76 BB". I used VC paper. I had the contrast turned all the way down for the D-76 B+ negative and no filtration for the other two. I set printing exposure for each print to make the whitest part of the fuzzy stuff in front of my great granddaughter's teddy bear the same.
    I got the expected high contrast from Gadget's Mistake, but grain and resolution were not seriously affected. Adding boric acid to make D-76 BB brought contrast back to near normal.
    Would there be a technical reason for making D-76 BB? Its pH is lower initially than that of traditional D-76 but its activity is nearly the same, at least on short strips. Its buffering capacity should be greater, both locally and overall, which should make a difference in the effect that different types of agitation make on gradations, but the effect may not be what one is looking for. In any case, it is another possible pictorial control.
    Gadget Gainer

  2. #21
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    That should have been 68 F. Here is a scan of the print to show gradations. That is my 2 1/2 year old great grand daughter, Daisy. She saw me setting up and insisted I take her picture.
    Attached Thumbnails Attached Thumbnails Reclining Nude 2.jpg  
    Gadget Gainer

  3. #22
    Ian Grant's Avatar
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    The 1947 British Journal Photographic Almanac says it's "A very excellent developer, which for some reason seems of recent years to have suffered eclipse". It's a developer that would probably al;si be ideal for making negatives for alternative processes.

    ian

  4. #23
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    I can't pretend to understand more than a quarter of what you wrote, but is the point of this to decrease activity in the highlights to try and get the developemnt of the highlights and shadows to become fairly even, to render lower contrast and higher tonal tetail?
    www.EASmithV.com

    "The camera is an instrument that teaches people how to see without a camera."— Dorothea Lange
    http://www.flickr.com/easmithv/
    RIP Kodachrome

  5. #24
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    If you don't understand it, then I did a poor job of writing it.

    Borax has a number of uses in photography, but if you buy developers ready-mixed or in powder form ready to mix, you may never handle borax as such. If that occasion arises, you may wonder if the borax you buy at the supermarket laundry section is suitable.

    There are two problems one can encounter when measuring out a precise weight of borax powder. One is impurity of various kinds, and the other is variation in weight due to water of crystallization. Borax will crystallize with either 5 molecules of water or 10 attached to a molecule of sodium tetraborate. The dry powder is likely to be amixture of the two forms, and the proportions may change over time due to humidity in the air when you do the weighing. High priced analytical grade borax may be guaranteed to be nothing but sodium tetraborate and water, but the easiest way to assure that you are measuring out the intended amount of the borate is to make a solution that is saturated at a certain temperature. Then at any higher temperature, the weight of sodium tetraborate per unit weight of solution will be constant and can be expressed as either the decahydrate or the pentrehydrate (different numbers, of course). For most of our uses, the weight of borax per unit volume of solution will be constant above the saturation temperature. At 20 C, a saturated solution of borax is 4.71%.

    As to purity, the process of crystallizing borax from a 100 C solution at or near saturation will leave most of the soluble impurities, including colloidally suspended particles, in the solution at 20 C. That solution is then discarded, The process may be repeated, each time with a loss of 47.1 grams per liter of discarded solution. When you are satisfied that the remaining borax is sufficiently pure, it my be left in the bottom of a container of pure water which will become a saturated solution whose borax content will be known.

    Is it worth the trouble? Probably not if all you want borax for is to make a batch of D-76 or the like. I and I'm sure many others have used 20 Mule Team borax from the grocery store for many years.
    Gadget Gainer

  6. #25
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    I'm sure you will all be happy to know I have saved Photographers Formulary from ruin. I just purchased my lifetime supply of photo quality borax---5 pounds. Actually, considering I'm in my 82nd year, I may have some left to leave my heirs.
    Gadget Gainer

  7. #26
    Murray Kelly's Avatar
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    Now you can use all the tubs of hardware store borax in your bath and not worry yourself if that kind of borax is good enough for photography! :-)
    Murray

  8. #27
    Murray Kelly's Avatar
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    BTW - I had a huge grin when I saw Daisy. My 2 Gd's are way too old to even tollerate a camera these days, more's the pity.
    Your'e right - there is a ton of grays in there. Just the way I like it.
    Murray

  9. #28
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    Here is a pretty good developer. You need 0.15 g. of Phenidone, 6 grams of ascorbic acid, and 400 ml of borax solution saturated at 20 C. That would be 188 grams of sodium tetraborate decahydrate if you were sure it is the decahydrate, but if there are any lumps in it, you can't be sure, so whether you go through the purification process or are sure that what you have contains only sodium, borax, hydrogen and water, you still don't know how much of the tetraborate you have. Therein lies the virtue of saturated solutions. A saturated solution of borax decanted at 20 C contains the equivalent of 4.71 grams of the tetraborate per 100 ml at any reasonable higher temperature.

    I suggest the usual ploy of making a solution of Phenidone in propylene glycol or glycerol. 10 g/l or 1 g/100ml is convenient. It only takes 15 ml of such a solution to make a liter of this soup.

    Mix the ascorbic acid and the 400 ml of borax solution with enough water to make 1 liter. Add the phenidone and you are ready to go. What, no sulfite? Yep. Try it without before you add any.

    Developing times will be like those you would use for D-76 full strength. A liter of this solution will do 10 to 12 standard rolls if you reuse it. How? The Phenidone is regenerated by the ascorbate, which is in great excess. Phenidone is noy very much affected by bromide in solution. I read many years ago that the activity of a PQ or PC developer would increase somewhat as bromide content rose. I read this in a translation from a Russian paper which was a translation from somebody else, while I was working for NASA, but I did use a similar developer which was much like Crawley's FX-19, though I didn't know it at the time..
    Gadget Gainer

  10. #29
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    Incidentally, if you want to get similar performance out by substituting Q for C, you will need sulfite to activate the regeneration of the Phenidone by the Q.
    Gadget Gainer

  11. #30
    Murray Kelly's Avatar
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    188g seems a lot of borax. Does it need all that to just buffer it? Or is it a matter of 'those damned dots'?
    Murray

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