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.
Glad to see that the article finally made it into the articles section. Could you do us a favor and show us all of the prints with the same amount of filtration? There is no way to tell the difference between the prints in a meaningful way if you give us different prints. It's like doing a study on plant growth and trimming one plant more than the others, a bad practice in scientific testing.
Ordinarilly I would do that, but the purpose here was, given that there was indeed 10 times more borax than standard, could a reasonably good print be made from a negative developed as if the D-76 were standard. That negative was the only one on which I used any printing filtration. Trust me, you don't want to use that much borax without adjusting the development of the negative! It doesn't even give a useful film speed increase unless you don't care about the shadows.
Originally Posted by drazak
PS: Reminds me of the old bawdy joke about the marriage between the circus midget and the lady giant:"Nose to nose his toes were in it and toes to toes, his nose was in it." That's about how it would be with highlights and shadows of that negative without very low contrast paper. No joy.
It is my understanding that Eastman long recommended up to (something like) eight or ten times the normal level borax for D76 in certain applications.
John, Mount Vernon, Virginia USA
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Nice piece of work. There are a lot of theoretical objections to practical matters voiced in this forum, but in the mantra of the experimentalist, "if it happens, it must be possible".
Would you consider examining non-photographic sodium carbonate and bicarbonate in a similar fashion? I'm pretty sure that the hot-tub and kitchen grades are rather pure; it has been stated (with authority but not necessarily accuracy) that anything but reagent grade contains chloride and is unsuitable for photography. Since I don't make up my own developers that often, I don't have a dog in the fight, but I've always wondered what the facts of the matter were.
In these days of home pools and hot tubs, there should be a reasonably cheap and accurate test for chlorine. The water in Newport News, VA had much chlorine. I used it for photographic work I did for the Norfolk and Peninsula Symphonies and the Old Dominion University Ballet without problem. I didn't realize how bad it was until I had been here in rural WV where the worst thing my well water contains is calcium, and went back to my old house for a night or two. The chlorine in the drinking water was so strong I didn't want to wash my face in it. Chlorides are a different matter and are certainly to be avoided in certain photographic activities, but my experience
Originally Posted by greybeard
at trying to use sodium chloride to reduce grain a la Microdol (they say) was that it took quite a lot to make a difference in practical photography.
There is certainly a version of D-76 that uses 8 g/l each of borax and boric acid as a buffer. What I tested here was similar, but 2.5 times as strong. With borates, the buffering capacity may be cranked up a lot more than the pH by such combinations. The pH certainly did not rise with my 20-20 combination over that with plain borax, but may have been stabilized.
Originally Posted by Anscojohn
The heavily buffered version is D76d.
Originally Posted by gainer
You might want to look at the Wellington Borax MQ formula that is said to be the developer D76 is derived from. It;s a clean working, long lasting relatively fine grain developer according to the Pritish Journal of Photography.
Wellington Borax MQ Film Developer
Sodium Sulphite (cryst) 23g
Water to 1 litre
Wellington & Ward were a British manufacturer of film, plates, papers etc who were bought by Ilford in the late 1930's.
Very interesting. I shall have to try it. Is there a British measure of weight that makes the weights come out 1, 10, 10 and water to 1 quart or gallon?
Originally Posted by Ian Grant
The onset of my interest in purifying borax was instigated by the assertion, made by PE and Kirk Keyes, that the 20 Mule Team borax from the supermarket is not pure enough for photo work, even though many of us have been doing so for years.