Calcium ascorbate

[Murray Kelly]

I bought, off the shelf, some ascorbate but realised when I got home that it was calcium ascorbate. Fine for the health freaks, but I seriously doubt its usefulness photographically speaking.

I suspect precipitations of insoluble calcium salts would make it pretty useless. But, I could be wrong.

Comments?
Murray

 

[Gerald C Koch]

I was not aware that they made this salt. While it would be good for your bones it would not be useful for photography. You are right calcium compounds would precipitate from developers.

 

[Mike Wilde]

I presume you were aiming for soduim ascorbate and mis-bought. I did find my supply of the vita C salt at a health suppliments store, and it has worked fine with Patrick Gainers PC-TEA formulae.

 

[Alan Johnson]

C12H14CaO12.2H2O.............+ Na2CO3..->....CaCO3....+2NaC6H7O6..+2H2O
Calcium Ascorbate dihydrate..Sodium Carbonate..Calcium Carbonate..Sodium Ascorbate
426.3................................105.99............->....100.09......2x198.11...
I think you can add calcium ascorbate solution to sodium carbonate solution to precipitate calcium carbonate which filter off leaving sodium ascorbate solution.Note this is anhydrous sodium carbonate, for washing soda crystals multiply the weight by 2.7.

 

[Denverdad]

Murray,

Someone on the Flickr caffenol group recently described their caffenol recipe using calcium ascorbate, in this thread.

I had to look it up, but according to this site, "Pure calcium ascorbate provides 114 mg of calcium per 1,000 mg of ascorbic acid"

 

[Murray Kelly]

Well, thank you all for the input. The most surprising was the Flickr Caffenol Group reference. I would never have guessed it.

Haven't checked with wiki but borates may be OK. Carbonates are definitely out. Apart from the above reference. Ca(OH)2? Definite maybe.

I could even try a simple test! Heaven forbid.

Murray

 

[Gerald C Koch]

Haven't checked with wiki but borates may be OK.
Murray

Borate buffers cannot be used with catechol developers, this includes the caffeic acid in caffeol. Catechol contains two hydroxy groups in the ortho position. This allows it to form a cyclic compound with the borate ion which prevents it from acting as a developer. All developer activity may be lost.