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Effect of ascorbic acid on film development

ymc226

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I have tried ascorbic acid in Rodinol and Rodinal/Xtol developer solution as recommended to decrease grain with stand development using slowish films (ASA 100) However, the negatives consistently came out underdeveloped (thin). When I omit the ascorbic acid, the negatives were good.

What does ascorbic acid actually do in regards to film development? I still don't want to give up on the technique as decreasing grain is something I want to accomplish. Is there anything else I could do, i.e. use less dilute developer or stand develop longer to get adequate development? Would using fast film make a difference?
 
I forgot to add that I am using 10gm of ascorbic acid per liter of Rodinol 1:100. Is this too much and does ascorbic acid act as a restrainer in this case?
 
Ascorbic acid at that level in dilute Rodinal will lower pH and slow down development. If you add AA, you must compensaate with alkali for the acid you have added.

PE
 
If you're trying to follow Gainer's recommendations, he used 4 grams sodium ascorbate (not ascorbic acid) per liter of Rodinal 1:50. In order to keep the ratios the same, try 2 grams/liter of sodium ascorbate if your Rodinal is 1:100. Gainer recommends that you use times for 1:25 dilution Rodinal only with Rodinal 1:50 + sodium ascorbate, so try starting with 1:50 Rodinal times with 1:100 + sodium ascorbate.

I've had good luck with Rodinal 1:100 + 2 grams/liter sodium ascorbate and reduced agitation on the 3-4 runs that I did with several films.

Lee
 
Thanks PE, what do you recommend for an alkali? (type and amount, if you please) The initial recommendation also included Borax 1/4 teaspoon per liter. If this is an alkali, it did not make any difference as the negatives remained under developed.
 
Thanks Lee, I've re-read the original recommendations (not Gainer's) and it specifies ascorbic acid. Does sodium ascorbate accomplish the same goal of reducing grain? Do you add any alkali to your developer solution as suggested by PE?
 
I have no idea what the pH should be. Lee has given good advice to use Sodium Ascorbate. But, the pH depends on amount and dilution.

The pH is a measurable quantity that could be specified in formulas, otherwise we get into this type of difficulty. If it is not, then we are on our own.

PE
 
I believe (correct me if I'm wrong) that the pH of equivalent amounts of AA or SA in developer solution is much lower for AA than SA. I may try using much less AA to see if it makes a difference in grain while still allowing full development.
 
See the two insets by Gainer in this article:

http://unblinkingeye.com/Articles/Rodinal/rodinal.html

You'll see your problem with using ascorbic acid referred to in the second Gainer contribution.

AFAIK, Gainer was the one who came up with the addition of sodium ascorbate to Rodinal and published it in PhotoTechniques, Jan/Feb 2002 pp. 27-29. He's also the one who recommended borax at 1 gram/liter with the 1:50 dilution, and I've used that basic ratio at 1:50 and 1:100 with the sodium ascorbate+Rodinal. The original article was called "Salt to Taste?", and tests were run with D-23 and Rodinal, both straight, and both with sodium chloride, plus Rodinal with sodium sulfite, and sodium ascorbate added. The sodium chloride was canning (non-iodized) salt.

Lee

BTW, you'll find Gainer's method for converting AA to SA in the unblinkingeye article as well as here on APUG (probably in multiple places) with a search.
 
Last edited by a moderator:
WOW, thanks Lee. I will print up the article and read it tonight. Too bad, I've just bought a pound of AA.
 
ymc226 said:
WOW, thanks Lee. I will print up the article and read it tonight. Too bad, I've just bought a pound of AA.
Click to expand...

You're still good. Just convert it with a little baking soda or sodium hydroxide (red devil lye) from the grocery store as per Gainer's instructions. I understand that the lye is getting hard to come by due to illegal drug manufacturing.

Lee
 

I have used 1 teaspoon of ascorbic acid plus 1/2 teaspoon of sodium bicarbonate (baking soda) mixed in a small amount of the water of dilution. Wait until the effervescence subsides before adding it to the Rodinal. If you are scrupulous, use 2.0 grams of ascorbic or erythorbic acid and 0.96 grams of bicarb.
 
A Mildly Alkaline Addition

Photo Engineer said:
Ascorbic acid at that level in dilute Rodinal will lower
pH and slow down development. PE
Click to expand...

Ascorbic acid, 10grams. Rodinal 10ml. Something any
image formed. Lowering the ph is a good strategy for
finer grain. Add some A&H bicarbonate of soda. I'd
think it a good choice. WATER stop. Dan
 
Thanks Gainer and Dan. I will add baking soda as I think that will prevent the underdevelopment that I am currently getting.

Dan, why a WATER stop bath instead of the usual acid stop bath?
 
If plain ascorbic acid slows down rodinal then it would be good option when using rodinal with constant agitation.
I have currently problems with rodinal 1:100 giving too fast developing times, and I would not want to go to 1:150, I would like to use 1:50 instead...
 

Check the pH before you go ruining any good pictures. At 1:100 it wont take much ascorbic acid to stop development entirely. The pH of sodium ascorbate alone will be about 7.5 It will not slow development, but speed it up. I have found that Rodinal 1+50 + 4 grams/l sodium ascorbate is about as fast as Rodinal 1+ 25. I don't think it's such a good idea to use ascorbic acid or the ascorbate to slow development of Rodinal. It might even be better to add sugar to increase the viscosity, but I haven't done it so can't give any warranty.
 
A BIG THANKS to Gainer and Lee. I bought baking soda (a mere $0.89 with tax!) and added it to my ascorbic acid as instructed. I used a combination Xtol/Rodinal 1:100, Borax with the baking soda/AA and got decent (maybe beautiful, negatives as I haven't printed them yet) but much better than without the few grams of baking soda.

It's amazing what a few grams of anything can make such a tremendous difference. Just shows how much of a newbie I am.
 
where do you find ascorbic acid powder??? vit. C chewable tabs??
 
heespharm said:
where do you find ascorbic acid powder??? vit. C chewable tabs??
Click to expand...

I find most grocery stores, especially the hippie-health-food ones, have powdered vitamin C along with the tablets; but this could vary by region, I expect. Any place that sells a significant line of vitamin supplements should have it.

Presumably you could grind up the tablets as well; in theory there could be effects from whatever binding agents are used to form the tablets, but I don't recall that people who have tried this have reported any actual problems.

-NT
 
heespharm said:
where do you find ascorbic acid powder??? vit. C chewable tabs??
Click to expand...

If you're near a Trader Joe's, look in the vitamin section. They sell Ascorbic Acid powder in 1 pound bottles for about ten dollars. I've used it successfully with Gainer's formulas for developing negs and prints.
 
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