Do I really NEED hypo clearing solution?

[Photo Engineer]

Dan;

KMnO4 is reduced to Manganese Oxide which is a black insoluable material. So even though the test just might squeak by, the Manganese Oxide formed will be as a light gray veil in the coating which will not wash out.

So, along with the possible destruction of the image, which is by no means proven or disproven, you will have the Manganese Oxide (actually, probably Manganous Oxide which is the most highly reduced form above forming the metal itself) that might precipitate out in the coating. Now this form is not assured either as Manganese has several oxidation states, but the possible formation of gray powdery material in my coating might turn me off a bit.

The test you describe has been long abandoned by all serious practitioners of analog photography as far as I know. I have never heard anyone advocate it at all in over 50 years except yourself.

The reaction relies on oxidizing hypo and reducing permanganate to a colorless form. Interestingly, oxidation of thiosulfate can result in forming sulfur, another precipitate. This again is by no means sure as it might just release sulfur dioxide. The bottom line is that this reaction is uncharacterized.

You had best use your permanganate to get rid of any odium tuckeri you have than use it as a wash aid.

Besides, permanganate is so reactive it is just too dangerous. If forms explosive mixtures on contact with most reductants even in dilute solution depending on the reagent involved.

PE

 

[dancqu]

You had best use your permanganate to get rid of any
odium tuckeri you have than use it as a wash aid. PE

I've not once suggested the use of potassium permanganate
as a wash aid. I've not any more than passed on a method,
detailed by P. K. Turner, of testing for complete washing.

IMO the method has merit especially where one wishes to
establish a regime which guarantees clean negatives or
prints. I can't believe P. K. Turner would, without any
work with the method, propose we use it.

At the very least I'd test the method before knocking
it. Has the man no credibility what-so-ever. P. K.
Turner. Someone familiar with his work? Dan

 

[Photo Engineer]

Dan;

Permanganate is a wash aid in the sense that it purports to aid you in determining the extent of your wash, no more and no less. Sorry if anyone interprets it beyond that, but you must understand that this is a destructive test which destroys both hypo and permanganate therefore making it "loosely" a wash aid, by reducing hypo content.

As for Turner, the dearth of his work and references to it are a testament to him. That includes the extent of use of the permanganate method that he recommends.

So, sorry. Never heard of the guy and a google search does not turn up much in terms of background. I'm sure that if his work was more significant, we would have learned about him in our work at EK, but he has never been mentioned (AFAIK) and I have never seen references to any work by him.

PE

 

[dancqu]

So, sorry. Never heard of the guy and a google search
does not turn up much in terms of background. PE

He was a contributor to the British Journal of Photography.
His book, the one I've mentioned, Processing Miniature
Film, is at this time for sale on Ebay. A buy at least
for those on that side. Dan

 

[Wade D]

I use Kodak Hypo Clearing Agent where I live. We are on well water which sometimes is in short supply in Southern California. Using the recommended times for washing film and prints has produced no adverse effects. I have negs and prints from the late 60's which look just fine.