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WolfTales
08-30-2009, 09:27 AM
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
08-30-2009, 03:06 PM
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
08-30-2009, 03:14 PM
There are a couple of sites that provide good info on the process....

The Daguerreian Society (http://daguerre.org/index.php)

New Dags (http://www.newdags.com/)

amuderick
08-31-2009, 09:36 PM
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
08-31-2009, 09:41 PM
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
09-01-2009, 06:03 AM
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
09-01-2009, 07:07 AM
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
09-01-2009, 11:42 AM
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
09-01-2009, 11:52 AM
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
09-01-2009, 03:29 PM
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!

totalamateur
09-01-2009, 03:29 PM
As and aside, there is a "newer" way to develop a daguerrotype plate which does not require Mercury. The plate after exposure is exposed to sunlight behind a red filter ( I think the specific color is very important to the process) and it develops the plate. I can't find the name of the process right now - but I'd think that it would be a load safer if one was interested in Daguerotypes. I had briefly considered it, since modifyling my 8x10 would be pretty easy - but then I saw the cost of copper plate and silver plating.

AgNO3 is quite costly enough, thank you very much. I'll lump that with the Cabon print process when I am retired and have both too much time AND money on my hands (God willing)

WolfTales
09-01-2009, 04:53 PM
Wow - extraordinary. That novel sounds intense, I'll have to check it out.

As for the silver iodide halides and the process - insane.

Fascinating. Mercury is so toxic!! Don't try it at home!

Chazzy
09-01-2009, 05:15 PM
As and aside, there is a "newer" way to develop a daguerrotype plate which does not require Mercury. The plate after exposure is exposed to sunlight behind a red filter ( I think the specific color is very important to the process) and it develops the plate. I can't find the name of the process right now

It's the Becquerel process, if I'm not mistaken.

PHOTOTONE
09-01-2009, 05:17 PM
It's the Becquerel process, if I'm not mistaken.

Yes and it is just about as old as the Mercury process.

amuderick
09-02-2009, 12:27 AM
The Becquerel process requires longer exposure times and the quality of the resulting image quality is not as good as the Mercury process. One day, with the right lab space, it is something I'd like to try.

Uncle Goose
09-02-2009, 04:16 AM
Mercury is certainly not a toy and if it's spilled you need a special vacuum cleaner to get rid of it. Otherwise you get the infamous fumes all around. Even breaking a thermometer is not a wise thing. I still have half a liter of Mercury standing here (safely sealed of course), don't have a purpose for it at this moment.

jnanian
09-02-2009, 06:21 AM
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....


naaah, you just need to have the plates ready next time
you cook some seafood ... in the dark of course.

totalamateur
09-02-2009, 02:29 PM
NExt in the alternative process forum - Tunadol and sashimetol developer.

Think wasabi can be used for toning?

Ray Rogers
09-02-2009, 09:43 PM
NExt in the alternative process forum - Tunadol and sashimetol developer.

Think wasabi can be used for toning?

Actually, you might not be far off track...
There is pretty good reason to assume photographically activite wasabi does exist!

BTW
I have used Matcha (green tea) powder as a "dry dye" before...

and
I have some Ika Zumi "squid ink"... any ideas on how to use that?

Ray

Dave Pritchard
09-02-2009, 09:49 PM
...
I have some Ika Zumi "squid ink"... any ideas on how to use that?
Ray

Faux selenium?