sodium sulfite v sodium bisulfite clearing bath permanganate bleach reversals

[removed account4]

hi

as i read Harvey W. Yurow's article on the unblinking eye regarding permanganate bleach reversals
i noticed he suggests one could use a variety of different things to clear the bleach bath.

he notes:

Substitution of sodium sulfite for sodium bisulfite in the clearing bath may enhance re-reversal
(Rahts). Other possible clearing agent to try are oxalic acid or ascorbic acid, to perhaps decrease the leveling effect.

but has no information on amounts of sodium sulfite or ascorbic acid might be used.
the original sodium bisulfite clearing bath is .5% ...
any ideas / starting points what the clearing bath's percentages might be if sodium sulfite or vit c would be used ?

i've got an email into the author, but in case it goes to a dead letter bin i want dot my t's and cross my i's ..

thanks in advance for your suggestions / help

john

 

[Gerald C Koch]

The bath must be acidic so you cannot simply use sodium sulfite as a substitute. It is very important that manganese dioxide not form in the emulsion despite what the author suggests. It is insoluble in water and once formed is hard to dissolve without harming the emulsion.

"Substitution of sodium sulfite for sodium bisulfite in the clearing bath may enhance re-reversal. Other possible clearing agent to try are oxalic acid or ascorbic acid, to perhaps decrease the leveling effect." It is important to note the use "may" rather than "can" in the preceding statement. He is suggesting something for possible future investigation and is not particularly suggesting their use.

My advice would be to stick to Ilford's or Kodak's recommendations.. There are just too many variables in reversal processing. In addition while permanganate maybe more environmentally friendly it is less reliable than dichromate. That is why I keep on suggesting Ilford's method if you cannot obtain dichromate. Dichromate ion can easily be destroyed before any discharge. Simply adding sulfite will convert chromium VI to safe chromium III

 

[Rudeofus]

John, have you thought about adding 5 g/l of Sodium Sulfite to a regular indicator stop bath? The indicator tells you whether the resulting mixture is still acidic, and if for some reason pH goes too high, you can add stop bath concentrate until pH is back down.

 

[removed account4]

hi gerald:

while i would love to use the ilford suggested reversal methodology, i really don't want to have anything to do with sulfuric acid, which is the reason
i am going the permanganate bleach+sulfate route.

thanks for your help, both in-thread and via PM !

John, have you thought about adding 5 g/l of Sodium Sulfite to a regular indicator stop bath? The indicator tells you whether the resulting mixture is still acidic, and if for some reason pH goes too high, you can add stop bath concentrate until pH is back down.

hi rudeofus

nope i haven't , and thanks for the suggestion !
i haven't bought stop bath in 20 years, so this gives me
a great reason to buy it !

do you think it will do the trick, clearing the permanganate bleach from my "will be white" sheet of photo paper ?
i am very keen on doing reversals, it seems much easier and less trying to reinvent a secret formula ( for silver gelatin ferrotypes ) ...
and i won't have to coat glass plates or metal plates, i can just use good old paper negatives, something i am very excited to do !

thanks !

john

 

[Rudeofus]

John, if you don't have a commercial stop bath, you would at least have Acetic Acid, yes? If you mix 5 g/l Sodium Sulfite into 1% Acetic Acid, you are still plenty acidic yet have the required amount of Sulfite to make a clearing bath comparable to what you get with 5 g/l Sodium Metabisulfite.

 

[Gerald C Koch]

You can use sodium bisulfate, phosphoric acid, citric acid, sulfamic acid, ... to acidify the bath. Sulfamic acid is crystalline and not liquid. Phosphoric acid is used as an acidulant in soft drinks. Lots of choices. My choice would be sodium bisulfate used to acidify water in swimming pooles. Brand names like pH Minus, pH Decreaser, ...

 

[removed account4]

jerry

i made the clearing bath at first by mistake with sodium bisulfate instead of bisulfite .. and i was told if i used bisulfate i would get streaking uncleared images ...
are you suggesting i can use a combination of the 2, the bisulfate to acidify the solution and sulfite to maybe clear the bleach ?
sorry for my cluelessness ... just trying to find a simpler way to make positives than reinventing a ferrotype developer

===

thanks rudeofus !
i will try that

 

[Gerald C Koch]

Yes you can use sulfate and sulfite. Think of sodium bisulfate as half neutralized sulfuric acid.

 

[removed account4]

Yes you can use sulfate and sulfite. Think of sodium bisulfate as half neutralized sulfuric acid.

thanks ! ...
any suggestions on how much bisulfate i should add to the water to acidify it ?

 

[Athiril]

Cheap white vinegar works too (3-5% acetic acid iirc).

 

[Rudeofus]

I would personally not use strong acids to make a sulfite clearing bath. If you lower pH too much, you release smelly and toxic Sulfur Dioxide. That's why I recommended Acetic Acid and not the other ones, and yes, it doesn't matter whether you use Sulfuric Acid or Sodium Bisulfate, both are too acidic IMHO, especially if one doesn't have a pH meter.

John, don't get hung up on the 1% number for Acetic Acid. Assuming that Athiril's numbers are correct, dilute white vinegar 1+3, add the 5 g/l Sulfite and be done with it. If the result smells like rotten eggs (Sulfur Dioxide), add small amounts of baking soda until it doesn't (watch out for the inevitable bubbling! ).

 

[Gerald C Koch]

Sulfur dioxide is soluble in water forming sulfurous acid. Adding acid to a dilute solution of sulfite is not going to release much gas into the air.