Rodinal w/sodium ascorbate

[john_hicks___]

I finally got around to making a batch of prints from HP5+ developed in Rodinal 1:100 w/4g/L sodium ascorbate added.

 

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They look _very good_ with the expected "Rodinal look" but somewhat less graininess than Rodinal with or without sulfite. The difference isn't huge, but it's worthwhile.

[marc_leest1]

John:

 

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I have a question: i can obtain easily Vitamine C (250g) but is has to

be transformed to sodium ascorbate. How to proceed ?

[georg_kern]

I heartfully agree with Mr. Hicks. Rodinal (im my case: 1/50) and

Sodium ascorbate make a great developer. Everybody who likes HP5 and

Rodinal (a lot of people, I think), but who has sometimes problems

with grain and E.I, should try this combination. But don't expect an

revolution, it's more of an evolution. However, development time has

to be modified.

I process HP5plus (120) as follows:

Jobo rotary Processor

270 ml Rodinal 1:50 with 1g Sodium ascorbate

20° C, 11 min (normal contrast). EI = 400

 

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"Vitamin C" can mean free acid or sodium ascorbate, which is the

sodium salt. Both come as powder and should act similiar, but may

affect the pH of the solution in a different way, so the effect won't

be the same. Also, the molecular weight won't be the same, so you

would have to use less ascorbic acid in grams (I don't have the

correct numbers).

There is no easy "home-brew" way to convert the free acid into pure

sodium ascorbate. But sodium ascorbate is cheap and easily available,

so don't start experimenting.

Regards

Georg

[ed b.]

According to Patrick Gainer: "Ascorbic acid [4 grams] is easily

converted to sodium ascorbate by either 1 gram of baking soda or 4.5

ml of 10% sodium hydroxide. If you use the baking soda, add it to the

ascorbic acid in a little water and let the fizzing subside before

adding it to the working solution."

 

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This information is in my article <a

href=http://unblinkingeye.com/Articles/Rodinal/rodinal.html>

Appreciating Rodinal</a>.

[conrad_hoffman]

Agree with all. I've been using this with FP4+ and find the

difference isn't dramatic, but definitely worth the extra few minutes

to make the addition. Nice to know the conversion to sodium

ascorbate, as the local health/vitamin stores only seem to have the

acid powder.

[john_stockdale2]

i read a posting quite recently in which the writer had used ascorbic

acid powder for this and the acidity apparently completely

neutralized the alkali in dilute Rodinal. Buying sodium ascorbate

should not be difficult. Maybe trying to neutralize ascorbic acid

with an alkali as suggested above would have to be done quite

accuately because of the very unbuffered nature of Rodinal

[esben_rossel_torbensen]

In Denmark where I live, chemicals aren't readily available, but I

find that my local pharmacy often is able to get me what I need.

[patrick_gainer]

If I ever said 4 parts of ascorbic acid to 1 part of sodium

bicarbonate (by weight), I'm very sorry. The absolutely properly

proper answer is the ratio of molecular weights, acid/bicarbonate,

which is 176/84. It is easy in teaspoon measure. 2 tsp acid and 1 tsp

baking soda (not powder)to the liter is close enough. If you try using

the acid without neutralizing it, you will likely not get an image. No

matter what you say about the potassium hydroxide in Rodinal, the

amount of it in 1+50 Rodinal is not enough to neutralize the ascorbic

acid.

Pat Gainer

[john_l_bagtas]

Question as regards Patrick Gainer's volumetric conversion into Sodium Ascrobate from 2 teaspoons Ascorbic Acid by the addition of 1 teaspoon of Sodium Bicarbonate - does this produce the 4 grams/liter of Sodium Ascorbate that is needed to be added to the Rodinal @ 1:50 for the reduced grain-effect?

[dan_smith]

Is the 4 grams per litre some kind of absolute found by testing? Or

am I OK using 4 grams per 8x10 developing volume? I stick with 10ml

of Rodinol syrup per 8x10 film unit whether developing one sheet of

8x10, 1 roll of 35mm or 8 sheets of 8x10. This is kept constant on

the syrup whether diluted 1+25, 1+75 or whatever dilution I use. I do

mix more than the minimum recommended amount each time so I generally

have more than the 10ml per 8x10 film unit in the working developer.

Any problems one can come up with for using the 4grams this way

rather than with a per litre blanket recommendation?

[ed b.]

I'm afraid I caused the confusion regarding how much bicarbonate to

add to ascorbic acid to converit to sodium ascorbate. Patrick

mentioned that you could add 4 grams/liter of sodium ascorbate to

Rodinal (1:50), so when he gave the conversion I assumed he was

referring to 4 grams of acid being converted. I have modified my

recommendations in my article <a

href=http://unblinkingeye.com/Articles/Rodinal/rodinal.html>

Appreciating Rodinal</a> to reflect the information he has provided

above. Patrick, if you have time I'd appreciate it if you would look

the article over and make sure all the information is correct. I

also show that you can convert using 10% sodium hydroxide, but I

don't think I have the correct ratio.

[patrick_gainer]

Answer to John Bagtas:

It's close enough for government work. I only weigh those ingredients

when I want to tell others what I'm doing and I want them to believe

me. Kodak, in earlier days when they gave out formulas, recommended a

scale that could measure in 1/10 gram units. Since we each establish

what time and temperature are right for development, consistency of

measurement is more important than absolute accuracy.

[patrick_gainer]

To Dan Smith:

use 2 grams of sodium ascorbate with each 10 ml of syrup and you

should be OK. 1 teaspoon is close enough. It dissolves quite quickly,

so you can keep it dry and add it to the solution just before use.

Pat Gainer

[dan_smith]

On the sodium ascorbate addition & development times and image

contrast.

I find, with my local tap water (very hard) that adding the sodium

ascorbate to the developer gives more contrast in a direct comparison

to straight Rodinol (1+75) as well a developing times about 1/3

quicker.

If I go back to using distilled water for mixing the developer, will

these findings still hold true?

 

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I emphasize that the development is done with working negatives, shot

back to back & processed within 20 minutes of each other (5x7's, 2

sheets of the same subject with no exposure changes, and 8x10's, 2

sheets of the same subject with no exposure changes). Not with

contact printing step wedges, though I will probably do that in the

future. In the 3 separate tests I have run, all using normal images

from a days shooting, the sodium ascorbate, whether 2 grams per 750ml

working solution (at 1+75 dilution) or 4 grams per 750ml working

dilution pick up more contrast than the normal Rodinol at the same

dilution without the ascorbate. Haven't worked enough with the 2

grams compared to the 4 grams to see any real difference. So far they

both look good. Will check a bit more when I have time, but usually I

end up testing on negs as I shoot rather than sitting in the darkroom

being "Mr. Wizard".

 

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In showing contact prints from the negs to others the contrast

difference is noticeable. The shadow detail in both seems the same so

in picking up contrast while cutting development time I don't seem to

be losing anything.

 

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Anyone else have info on the differences, dilutions & results?