I agree that Calcium Ascorbate is a great supplement. No "sour stomach" after taking vitamin C. No opinion on its use in a developer, but it is the only kind if vitamin C I take.
It would probably be both simpler/cheaper and more reliable to use sodium carbonate to replace the calcium in the ascrobate you have. Mixed in solution with a slight excess of the carbonate, you'd get a slightly alkaline pH, which would prevent the carbonate from staying dissolved, and the precipitate would then filter out readily with a coffee filter or similar. The resulting sodium ascorbate solution would then be completely usable in developing. It would probably be desirable, both from a chemical standpoint and to avoid dilution, to use the minimum amount of water to perform the precipitation, and of course you'll want to weigh both components and do a little chemistry work to verify what strength the resulting solution comes to, so you can measure it accurately.
Sodium carbonate is really, really, cheap, BTW -- you can get it in the monohydrate form in a box marked "Arm & Hammer Super Washing Soda" at most larger grocery stores in the United States (in the laundry section, right next to the 20 Mule Team Borax); the box holds something like three pounds, and will cost you less than three dollars.
Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.
Originally Posted by Donald Qualls
And it smells nice, too. Nice fresh laundry smell.
Thought I'd bring you folks up-to-date on my calcium ascorbate use; I haven't tried it as a film dev., but it works well in print dev. E-72 from "The Darkroom Cookbook".
No, because if you try to dissolve calcium ascorbate in water you will have nothing but precipitate to begin with. Don't bother to try anything called "Ester C". The body uses these as fat-soluble vitamin.
Originally Posted by Ole
It will cost you less in time and money if you find ascorbic acid. Sodium ascorbate is useful in some applications, but it is not very soluble in glycol or TEA. It is the best stuff to get for perverting Rodinal or making an Xtol expedient, but you can also easily make it with ascorbic acid and baking soda. It depends on how varied your uses might be.
Even soluble calcium or magnesium compounds should not be used in solutions along with carbonates. Magnesium carbonate makes a very white cake, but unless that is what you are trying to make, even hard water should be avoided or doctored with a sequestering agent like EDTA.
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Just to be sure, I tried dissolving 3 calcium ascorbate tablets, one each in 1)tap water from my well, 2)potassium carbonate solution and 3)HCl (muriatic acid). The water softened the tablet but did not dissolve it, as expected. Strangely, the potash solution, a very strong one as used in Pyrocat HD, did not even soften the tablet after standing all night. HCl made a slurry of most of the tablet. I was expecting calcium chloride and ascorbic acid. Of course, the tablets have other stuff as filler, etc. Adding the carbonate to this slurry made lots of foam, which may have contained calcium carbonate and potassium ascorbate along with the CO2 from excess acid.
The E-72 formula must be in a later edition of The Darkroom Cookbook than the one I have. Does it simply substitute ascorbate for hydroquinone?
Ca-ascorbate should be very soluble in water though....
Here it doesn;t give data but I guess it should be more than 100 g/l
maybe the stuff you got has some non-soluble filler.
Mama took my APX away.....
Originally Posted by gainer
Sort of. It subs ascorbic acid for the Q. Here's the recipe:
Phenidone 0.3 g
Sod. Sulfite 45 g
Ascorbic acid 19 g
Sod. Carb. mono 90 g
Pot. Bro. 1.9 g
water to make 1 liter
This is from the 2nd edition of the Cookbook.
I guess all that carbonate takes care of the acid problem.
I've been using up my bottle of Calcium Ascorbate (sold as Vit. C in the local health-food store). I didn't want to use it in a formula for film, but it seems to work ok for paper.
You could save money by leaving out the sulfite. It doesn't protect ascorbic acid from aerial oxidation. Ascorbic acid protects the phenidone.
Originally Posted by jim appleyard
I don't see how you can dissolve calcium ascorbate in a carbonate solution without precipitating a bunch of calcium carbonate. In order to get the equivqlent of 19 grams of ascorbic acid, you would need a lot more than 19 grams of calcium ascorbate. I haven't worked out the ratio, but it's simply proportional to the molecular weights, allowing for the fact that each molecule of calcium ascorbate has two molecules of ascorbic acid - 2 H. On second thought, maybe the ratio is not so great.
Glad to know I can save a $.
Oh, believe me, I get precipitate and perhaps this isn't the ideal dev mixture in the world; I'm just using up the cal ascorbate.
I thought of adding it to beer, to make a health drink, but why ruin a perfectly good good bottle of cal ascorbate by adding it to Old Milwaukee Light?