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Mercury intensification

hernan zenteno , Oct 08, 2013; 07:29 p.m.

Hello. I have a bottle of mercury intensifier that I preserved only for emergencies. The thing is that after 15 or more years I want to use it but I don't remember a few things. After put the negatives in the intensifier I need to take off the white layer that forms using a solution of some developer or a solution of sodium sulfite but I don't remember what kind of solution. And the other thing is the last negative I used with this type of intensifier is a bit fade. Can I wash and use selenium to make permanent the mercury intensifier or are there any incompatibility? I know that I have to use gloves and that mercury is poisonous. Many thanks in advance


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Glen H , Oct 08, 2013; 10:22 p.m.

Seems that there are four choices ...

Undisplayable photo attachment:
Intensifier IN4 -- IN4.pdf)

John Stockdale , Oct 09, 2013; 01:09 a.m.

Do you know which mercury intensifier you have? I have some instructions for VMI (Smith Victor) including some instructions for after treatment.
Incidentally, I wouldn't recommend relying on gloves. I'm no expert, but some mercury chemicals are surprisingly poisonous. I know this isn't the mercury compound that you have, but this is worth reading:

hernan zenteno , Oct 09, 2013; 08:12 a.m.

Ah, I knew that there were a reason to use developer (dektol) or sodium sulfite. One is more strong that the other. Many thanks Glen.
John, I finally did the intensification with sodium sulfite using gloves. All was ok, hope to not dead in six months. But for what I remember this solution is not so dangerous, obviously you can't drink it and must take it with extremely care. The kind of intensifier I used is from a local mark, Romek, but they don't do anymore this product and I can't find the instructions. I suppose that is very similar to Victor or old Kodak intensifiers. I will appreciate to know the instructions to compare with the other sent by Glen.
The only thing I really don't have any clue is if I can do more archival the film processed with mercury intensifier applying a bath of selenium to avoid the fade thru the years. Anyone knows if this is viable? Or any other method to avoid the fading?

peter carter , Oct 09, 2013; 09:03 a.m.

I would guess a selenium bath should prevent the fade.

I would also guess the chromium version would not fade, as you re-develop to completion.

hernan zenteno , Oct 09, 2013; 09:37 a.m.

Hi Peter. I think so but what worry me is if some chemical reaction could be poisonous or play at the inverse staining the negatives or fading them more fast. I don't know if after mercury intensification I can use a simple selenium bath cause the emulsion must be composed by other chemicals after the intensification process. But I have no clue about chemistry at that level. By now I will scan the files I have interest and will do some back ups.

Alan Marcus , Oct 09, 2013; 03:58 p.m.

Mercury Intensifier:
Improves printing density of thin flat negatives.
Water ----- 750ml
Potassium Bromide 10 gr.
Mercuric Chloride 10 gr.
Mix at room temperate, add water to make 1 liter (1000ml)
After mixing, use undiluted on negatives known to be thoroughly washed.
Immerse negatives and agitate. Image will beach away. Wash bleached negatives in stagnant water bath containing a few drops of hydrochloric acid. Re-develop in a 5% solution of sodium sulfite. You may substitute a non-staining developer such as Kodak D-76 formula. If this developer solution is to be stored, keep in mind that a scum forms in the bottle. The scum will not affect the developers working properties but the fluid should be filtered before treating additional negatives.

John Stockdale , Oct 09, 2013; 04:05 p.m.

There is some info at this article by Steve Anchell. If the link doesn't work just google "anchell vmi" and it will come up. Sodium sulFIDE is used to make the image permanent.

hernan zenteno , Oct 09, 2013; 06:36 p.m.

Many thanks Alan and John. Appears that sulfide is what I need. Now I will have to ask where I can get that. Is not a common substance used in the darkroom. At less by me. Equal I will need to search the formula I used by Romek cause I saw that there are several differences between the mercury intensifier formulas. Maybe the permanence could be reached by the same chemical. Is nice to see that are a lot of people still in this kind of things. Here in Buenos Aires I am pretty like a dodo.

peter carter , Oct 09, 2013; 08:36 p.m.

Try a "brew you own" store. They use it to sterilise the bottles.

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