Mercury Intensifier

[koraks]

In my youth, mercury was everywhere. In thermometers mostly, and we rolled balls of mercury around in our palms in science class. Don't swallow it, don't get it on you and don't breathe it.

There's a distinct difference between metallic mercury, which has limited bioavailability, and salts of the metal like the mercury chloride used in an intensifier formula. The latter is far more dangerous.

 

[Donald Qualls]

The Minimata disaster was a result of organic mercury compounds. Some of these are so toxic that a single drop of a solution on the skin can result in severe brain damage or death.

Mercury intensifier ought to be made with inorganic mercury salts -- halides, nitrate, or similar -- which are relatively innocuous. Yes, metallic mercury isn't a good thing to handle indiscriminately, but it takes large amounts of exposure (as was the case with Victorian hatters) before it does significant damage. School kids playing with a couple drops of mercury from a broken fever thermometer weren't in much danger. Nor are Daguerreotypists who take some basic care to exhaust their mercury fumes from their work area.

As noted above, wear eye protection, a respirator, use an exhaust hood, and wear heavy impervious gloves when working with mercury intensifier, and you should be fine. The real question is, does anyone have the formula for that Victor's Mercury Intensifier? If not, it doesn't much matter how safe you can or can't be with it...

 

[Donald Qualls]

salts of the metal like the mercury chloride used in an intensifier formula. The latter is far more dangerous.

True as stated, but inorganic mercury salts still have rather low solubility -- mercury halides are more soluble than silver halides, but much less so than, say, table salt. Reasonable precautions in handling and mixing (and waste disposal) should be sufficient.

 

[Alex Benjamin]

does anyone have the formula for that Victor's Mercury Intensifier?

You have it in this thread, post #2.

The Smith-Victor Company went out of business many years ago, and commercial availability is doubtful because of restrictions on the use and shipment of mercury compounds. After the company went out of business, the formula was released and published in the Dignan Newsletter:

Smith-Victor intensifier
Mercuric chloride 13 g
Magnesium sulfate 60 g
Potassium iodide 30 g
Sodium sulfite 15 g
WTM 1 l
Filter sediment as necessary.
Use in a white tray. Immerse wet negative emulsion side up. Action is powerful. Process for 5 seconds to 10 minutes. Most negatives will take 15 seconds to 2 minutes, but intensification can be continued up to 10 minutes. Wash for 10 minutes. If negative mottles in the wash, clean off the uneven area with cotton. If problems persist, treat negative in a plain hypo solution and start over. It works most strongly on the weak areas of the negative.

And here's Krause's formula that he got from Mr. Smith of the Smith-Victor Company, as noted in Darkroom (p. 109), in oz. and gallons instead of g. and liters:

mercuric chloride NF powder - 1 3/4 oz.
magnesium sulfate, purified dried powder - 8 oz.
potassium iodide USP granular - 4 oz.
sodium sulfite, anhydrous photo (desiccated) - 2 oz.
water to make one gallon

 

[Donald Qualls]

You have it in this thread, post #2.

Yep, found it after I posted. Thanks!

I doubt it's worth my effort to try to get mercuric chloride anyway, but it's nice to know what's possible.

 

[koraks]

Did a quick check; an online store here in my country retails it for the equivalent of roughly $10/oz.
No, I'm not putting in an order...I'm fine with my chromium intensifier as it is!

 

[ic-racer]

Sure mercury has had some crazy uses (i.e. Syphilis) but I'd be concerned about how people dispose it because I don't want it near me. Sure, I have rolled balls of liquid mercury in my hands, but the threat in the environment is you can't see it before you ingest it.

 

[reddesert]

People want to believe in magic bullets - especially hard to obtain or long-gone intensifiers, secret-formula developers, obscure lenses, whatever. The more out of reach something is, the more ineffable its effects must be.

The problem with mercury compounds isn't just whether you can manage the immediate hazard to yourself working in the darkroom, but whether you can responsibly contain and dispose of it, what happens to your supplies after you retire, etc. Some dead and gone things are best left un-resurrected.

 

[ic-racer]

I used to live near the Krejci Dump.

Upon investigation and testing of the site between 1986 and 1987, many toxic substances were found at the site, including polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAH), arsenic, dioxin, heavy metals, and other carcinogens.[1] Thousands of leaking drums were found on the property.[3] These drums contained waste from industrial processes, including paint, ink, herbicides, pesticides, solvents, and industrial sludge.[3]