Making mercury developed dags

[Barrutia]

Hello forum.
I´ve bought all the material needed to make mercury developed dags to a friend of mine.
He tought me the process 2 years ago, and as he´s moving to spain he gave me the boxes, plates, iodine, mercury and all the polishing materials needed.
I´ve been making tests today without success.
I polish the plate (using 6x6cm plates for my rolleiflex) with 4 different rods. I read something about spraying distilled water between polishing and final buffing, but I´m steping through that process.
For the last buffing I use a special cotton. 2 minutes with the same small cotton.
then sensibilization with iodine til I get through the first cicle to the golden tone. (would I get an image If I use the plate with the pink or green tone?).
One of the doubt´s I have is regarding exposure times. I use f2,8 of my rollei and tried with 1, 2 and 5 minutes in a cloudy day. Is there any scale of exposure times according to different light situations?

Then I develop with mercury at arround 60/70º for 1 to 3 minutes and check the results each min.
I tried 5 times today and didnt get any image. Sometimes i got "water" condensation in the plate when developing.
Last but not least, I use pure silver plates.
Tomorrow I´ll try with another plate. Maybe thats the problem.


any advices, corrections?

Thanks a lot!!

Agustin Barrutia
Buenos Aires, Argentina
msn:
a_barrutia@hotmail.com

 

[DimDim]

Hi there,

Take a look at www.newdags.com.
There is a quite comprehensive overview of both the mercury and Bequerel way of working.
But mind that when developing with mercury you need to sensitize the plate 3 times: first by using iodine, then bromine and then iodine again.
Newdags shows some examples of the various coating colors and the obtained results.

Good luck.

 

[JG Motamedi]

In addition to the suggestion above, I think you should read through a few old manuals. SD Humphrey's "American Hand Book of the Daguerreotype" is a good place to start. There is also a good handbook written in Spanish, although at the moment I can't recall its title or author.

 

[Barrutia]

Thanks guys for the suggestions and links.
I just tried with another plate and finally got my first dag!!!! yayy!!!!!

Some coating problems, as the image has an overexposed portion.
THe problem was the other plate.
For how long do you develop? 1 to 3 minutes is correct?

I´ll upload the image as soon as I digitalize it.

THanks a lot!

Agustin

 

[JG Motamedi]

Like everything with Daguerreotypy there are no certainties, so I can't tell you how long you have to develop. I have found that four and a half minutes at 170F (76C) works for me, but it all depends on plates, exposures, humidity, altitude, and who knows what else.

Again, read the manuals, they will provide more and better guidance than anyone here.

And of course stay safe! Watch the fumehood exhaust and do regular and exhaustive testing of your system. Unlike most photochemicals, mercury will not only kill you, it will kill your neighbors, and your neighbors' neighbors, and your neighbors' neighbors' neighbors, ad nauseum...