Mercury Developer

[WolfTales]

Hi all,

I read that Monseigneur Louis Daguerre used mercury to develop early Daguerrotypes. How would mercury act as an amplifier in this situation? Looking into the history of photography...

Does anyone know and be happy to share of course? If not no worries, I realize that this is pretty deep somewhere.

Thanks much

[PHOTOTONE]

It was the fumes of mercury, that bonded with the latent image on the silver coated plate that made the image visible. Mercury is heated and the plate is put in a box over the mercury and the heated mercury gives off fumes that "develop" the image on the surface of the sensitized silver plate. I don't think it would work at all with gelatin emulsions.

[resummerfield]

There are a couple of sites that provide good info on the process....

The Daguerreian Society

New Dags

[amuderick]

Copper plate is coated with silver. Silver is polished to remove all trace of oxide. Then silver is exposed to Iodine vapor. Forms Silver Iodide which is light sensitive. Plate is exposed. Mercury vapor reacts with the unexposed silver to form a silver/mercury amalgam which is 'black'. Then it is sealed under glass to prevent further oxidation/corrosion. Nasty process. Fascinating though.

The images are worth seeing in person. Most antique store 'daguerrotypes' aren't. Real daguerrotypes can be viewed as positives or negatives depending on the angle of the light.

I'm looking forward to attending the Daguerreian Society meeting in Philadelphia this year.

[jnanian]

Copper plate is coated with silver. Silver is polished to remove all trace of oxide. Then silver is exposed to Iodine vapor. Forms Silver Iodide which is light sensitive. Plate is exposed. Mercury vapor reacts with the unexposed silver to form a silver/mercury amalgam which is 'black'. Then it is sealed under glass to prevent further oxidation/corrosion. Nasty process. Fascinating though.

The images are worth seeing in person. Most antique store 'daguerrotypes' aren't. Real daguerrotypes can be viewed as positives or negatives depending on the angle of the light.

I'm looking forward to attending the Daguerreian Society meeting in Philadelphia this year.

it depends on which antique stores you go to

[Nancy Gutrich]

Those of you interested in fiction might want to read THE MERCURY VISIONS of LOUIS DAGUERRE by Dominic Smith...it gives an interesting overview of his life, times and the effects of mercury...

[bsdunek]

Those of you interested in fiction might want to read THE MERCURY VISIONS of LOUIS DAGUERRE by Dominic Smith...it gives an interesting overview of his life, times and the effects of mercury...

Agree - I really enjoyed this book. As a historic novel it's quite good.

[greybeard]

A bit of photographic trivia: while mercury will not "develop" a silver-gelatin emulsion, mercury vapor will hypersensitize ordinary film. My father was taught this as part of his Army counterintelligence training in the late 1940s. It seems to have involved putting the film (or plate, back then) in a box with a drop or two of metallic mercury, and letting it sit for a while before exposure. This was at a time when "normal" speed film was ASA 25, or maybe 50, and "fast" film was all of ASA 160!

I should try it the next time I break a mercury thermometer....

[Photo Engineer]

Too much mercury at the wrong time will fog film emulsions. Most all emulsions pre-1970 contained mercury in them for its properties in increasing speed and in preserving that speed and curve shape.

Anyone who uses mercury in a serious manner ends up risking becoming as mad as a hatter! The felting process to make hats involved the hatter chewing the felt when mercury salts were present. OTOH, in the French court of the same time, people drank mercury to feel it jiggle in their stomachs while they pranced around at the ball.

Mercury was used in many cosmetics for its color. This led to many women and men having severe ulcerations on their faces due to the mercury.

PE

[Kirk Keyes]

The felting process to make hats involved the hatter chewing the felt when mercury salts were present.

That's why I sit around and chew the fat, and never the felt...

My Merck Index from the 1950s listed metallic mercury as a cure for constipation. I bet that was a lot of fun!