I Think Have A Vitamin C Deficiency

[Snapshot]

Hi All,

I'm having difficulty determining if I have a problem with a batch of ascorbic acid. I attempted to use this ascorbic acid in a couple of developers, both of which had anemic results. In addition, I've attempted to make sodium ascorbate with it and it appeared to me that there wasn't much in the way of 'fizzing' when I added sodium bicarbonate to the ascorbic acid.

The ascorbic acid is store bought from a local pharmacy (with an expiry date well into 2008) and I think that it that's why it has less activity. I've heard that store purchased vitamin C is not as active as industrial use ascorbic acid.

Has anyone had similar experiences with their ascorbic acid?

 

[psvensson]

Yup, you could have "Vitamin C" that's partly dehydroascorbic acid. It works the same as ascorbic acid in the body but doesn't develop film. I use C-1000 from the Vitamin Shoppe, and find I have to use 40 percent more than straight ascorbic acid.

I don't think this accounts for the lack of fizz, though.

 

[Snapshot]

Well, there was some fizzing, just not as much I was anticipating. It apppears that I may have dehydroascorbic acid. I guess I'll have to use more of it in my formulas. However, is it possible that in doing so it may throw off the developer?

 

[psvensson]

I think it may throw off the pH, but the buffer in most developers will minimize the effect.

 

[john_s]

Why not contact the manufacturer? They ought to be able to tell you what's in it. If it's not just ascorbic acid, you might be better eating it, and buying some of the real stuff.

 

[gainer]

Dehydroascorbic acid is one of the products of development by ascorbic acid. It is why the byproducts of ascorbic acid developers are acidic. The body converts ascorbic acid to dehydroascorbic acid so that it may pass the brain blood barrier and reconverts it to ascorbic acid on the other side. The transformation reaction is something our bodies can do, but for photographers it would be impractical if not impossible. It's so much easier to get ascorbic acid or erythorbic acid, its mirror image. If you plan to use it as the vitamin as well as a developer, do not get erythorbic acid.

 

[Snapshot]

Why not contact the manufacturer? They ought to be able to tell you what's in it. If it's not just ascorbic acid, you might be better eating it, and buying some of the real stuff.

I contacted the manufacturer and they'll get back to me shortly. The person fielding the question didn't have an answer at the moment. I guess they don't too many people calling asking the percentage of dehydroascrobic in their product.

 

[Snapshot]

Dehydroascorbic acid is one of the products of development by ascorbic acid. It is why the byproducts of ascorbic acid developers are acidic. The body converts ascorbic acid to dehydroascorbic acid so that it may pass the brain blood barrier and reconverts it to ascorbic acid on the other side. The transformation reaction is something our bodies can do, but for photographers it would be impractical if not impossible. It's so much easier to get ascorbic acid or erythorbic acid, its mirror image. If you plan to use it as the vitamin as well as a developer, do not get erythorbic acid.

Thanks for the information. I didn't realize how complex ascorbic acid and their reactions can get.

 

[Kevin Caulfield]

Sorry, but I can't help myself. When I read the title of this thread, I was going to suggest drinking a lot of orange juice.

 

[john_s]

I contacted the manufacturer and they'll get back to me shortly. The person fielding the question didn't have an answer at the moment. I guess they don't too many people calling asking the percentage of dehydroascrobic in their product.

I have found such questions to take a while to answer, perhaps because they don't have any idea who you are or why you're asking. And as you say, such calls are infrequent. Maybe sometimes they think you're planning to sue them because the product didn't work.

I have found it helpful to say I'm using the product for black and white photography, not for use as a food supplement, antifreeze, soap ingredient or whatever they may sell their products for. That often results in helpful responses because we B&W photographers are held in such high esteem. ......Or maybe they're just feeling sorry for the eccentric old guy.