Chromium intensifier + fiber prints

[M Carter]

So I have one of Tim Rudman's printing books (not the toning book), where he mentions chromium intensifier for prints, a recipe using hydrochloric acid. I have the forumlary's chromium intensifier (which uses a powder vs. hydrochloric) and tried it on some test strips.

I'm quite enamored of it for certain uses - warmtone paper go a cold, cold black, with a hint of blue in the highlights. Really useful for things like undercooked lith prints, or for a deep cool tone by printing a bit lighter. More tests to come, multiple passes, different developers, weak devs, etc.

My question, somewhat out of curiosity - how "archival" is chromium for paper? I do sell a few prints, more just curious. Or can it be followed be selenium or gold? Very curious about this stuff, it's really got some powerful potential and its thing is much different than selenium or variable sepia.

 

[Gerald C Koch]

I would suspect that the intensifier would damage the paper backing.

 

[M Carter]

I would suspect that the intensifier would damage the paper backing.

Well, Rudman has a few pages on chromium intensifier for prints, with no warnings - he's usually pretty thorough, and lists it as one of his primary toning techniques. He does state "potassium dichromate can also do wonders for subsequent toning processes and can be worth doing for this reason alone". He also mentions farmer's reducer after dichromate, saying to wash the print for an hour before farmer's or some of the black enrichment will be lost.

Since the process is essentially a bleach and tone process, with the print redeveloped to completion in full-strength paper developer (and thus no mention of fixing afterwards), I'd assume it's stable and perhaps can go on to selenium or gold.

Wondering if anyone has more than a guess about it though?

 

[Gerald C Koch]

Once again I must point out that Rudman is not a chemist. Did he prove that chromium intensifier is achivally neutral. I doubt it. Potassium dichromate is a powerful oxidant which easily chews up organic materiall. A mixture of potassium dichromate and sulfuric acid is routinely used in labs to remove organic material from glass reaction vessels. It is very effective. A better choice would be potassium permanganate which IS used in intensifier processes especially for old and faded prints. There is a video on the web demonstrating how to do this.

There is an additional problem in that chrmium remains in the intensified image. Kodak warns that In-4 is not archival at least in my Darkroom Data Guide.

 

[Ian Grant]

Ilford IT-8 Toner works perfectly with FB prints. Guess what Part A the bleach is the same as Chromium Intensifier, Part B is a Pyrocatechin re-developer. There were only FB papers when the Toner was first published.

The first time I used IT-8 was in the mid to late 1970's and the prints are still fine 40 years later. As far as I know the Chromium stain is permanent, I've never seen anything stating it's not.

Ian

 

[Arklatexian]

Once again I must point out that Rudman is not a chemist. Did he prove that chromium intensifier is achivally neutral. I doubt it. Potassium dichromate is a powerful oxidant which easily chews up organic materiall. A mixture of potassium dichromate and sulfuric acid is routinely used in labs to remove organic material from glass reaction vessels. It is very effective. A better choice would be potassium permanganate which IS used in intensifier processes especially for old and faded prints. There is a video on the web demonstrating how to do this.

There is an additional problem in that chrmium remains in the intensified image. Kodak warns that In-4 is not archival at least in my Darkroom Data Guide.

This is a question regarding your "QUOTE". Was this glass cleaner used for the same purpose as the one we used in chemistry classes made with nitric acid and. potassium dichromate? As I remember, it was really nasty stuff.. My only experience with chromium intensifier has been with film. Much preferred the old mercury based stuff but know and agree with why it was "outlawed".......Regards!

 

[Gerald C Koch]

This is a question regarding your "QUOTE". Was this glass cleaner used for the same purpose as the one we used in chemistry classes made with nitric acid and. potassium dichromate? As I remember, it was really nasty stuff.. My only experience with chromium intensifier has been with film. Much preferred the old mercury based stuff but know and agree with why it was "outlawed".......Regards!

Yes, a strong acid releases chromium trioxide from dichromates which is a very poqwerful oxidizing agent.

 

[Ian Grant]

My question, somewhat out of curiosity - how "archival" is chromium for paper? I do sell a few prints, more just curious. Or can it be followed be selenium or gold? Very curious about this stuff, it's really got some powerful potential and its thing is much different than selenium or variable sepia.

I'd happily sell a print that's been toned in Ilford IT-8 Toner. As I pointed out before the bleach is the same as Chromium Intensifier, and non of my many Kodak books/manuals makes any reference to instability in fact just the opposite. It's IN-1 the Mercury/Cyanide Kodak Intensifier that's not stable, Eastman Kodak state IN-4 is more permanent.

Ian

 

[M Carter]

I'd happily sell a print that's been toned in Ilford IT-8 Toner. As I pointed out before the bleach is the same as Chromium Intensifier, and non of my many Kodak books/manuals makes any reference to instability in fact just the opposite. It's IN-1 the Mercury/Cyanide Kodak Intensifier that's not stable, Eastman Kodak state IN-4 is more permanent.

Ian

Good to hear - it's really a cool thing to have in your back pocket.

 

[M Carter]

This is a question regarding your "QUOTE". Was this glass cleaner used for the same purpose as the one we used in chemistry classes made with nitric acid and. potassium dichromate? As I remember, it was really nasty stuff.. My only experience with chromium intensifier has been with film. Much preferred the old mercury based stuff but know and agree with why it was "outlawed".......Regards!

I've seen examples of what mercury can do for a negative, not just for a rescue mission but as a creative tool. Doubt I'll veer get my hands on some. Kind of like cadmium papers I guess... thing of the past.