[photolytic]

Hi Larry,

It sounds like you had a rather frustrating experience.
It actually took me 6 or 7 experiments before I had success with it but then I had no one to tell me if it worked at all.
Your exposure sounds long enough but your fuming might have been too long.
Not only does a thicker coating slow down the plate a bit but it hides the developing image until the Dag is fixed.
If you had fixed your Dag you might have seen an image.
The best way to see the developing image in the vacuum chamber is to shine a red light at a low angle across the surface of the plate. I use a rubylith filter on my flashlight but a red or yellow LED would work well also

You don’t mention the type vacuum apparatus you used or the temperature.
The plastic vacuum desiccators that I originally used did not hold vacuum well enough so I would recommend using glass apparatus. For best results the vacuum must remain at or above 23 inches of mercury and the temperature above 15C during the developing process. If you are in doubt whether you have a vacuum leak, you can leave your vacuum gage attached to the vacuum chamber and check it just before opening the desiccator.

During fuming, you should "take a look" at the plate during the coating process to monitor the progress. So long as you finish off the fuming process with a final exposure to iodine fumes in the dark or under a safelight this light exposure will not fog the plate. This light exposure should not be confused with flashing or hyper sensitizing the plates with light after all fuming is complete.

If you have read Susan Barger’s book or my second article "The light after the Bromine" in the resources section of this forum, you will see that weak light exposure, particularly during bromine fuming, actually increases the speed of the plates. This In-process light breaks down some of the silver halide on the plate into atoms of metallic silver which Barger calls Photolytic silver. These photolytic silver atoms combine with the latent image of the Dag forming a stronger image.

Good Luck, John

[photolytic]

The answer you seek is contained in Appendix c, page 27, of my article "Frozen in Time" which has been posted in the resources section of this forum for about a month now. In my research, plates sensitized with iodine and bromine and held for 2 minutes up to 8 hours before being exposed and developed with mercury, actually tended to get more sensitive with time. Iodized plates keep even longer, especially if kept dry. In 2002 I took the Daguerreian Society group portrait on plates which had been sensitized 4 days earlier. Sealed in plastic bags and kept cool, they survived a 4 hour flight (2 stops) from Chicago to Sacramento California in my carry on luggage. After taking the Dag the plates were shipped back to me in Chicago in an ice cooled container and developed successfully 2 days later. The results appeared on the cover of the Daguerreian Society newsletter Vol. 14, No 6.

APPENDIX C
SENSITIVITY CHANGES IN DAGUERREOTYPES PLATES AFTER COATING
Four quarter plates were fumed simultaneously for 15/10/5 seconds over I/Br/I under approx 1fc of light at approximately 18 C. A 3rd I fuming of 2 sec was done under a safelight. The plates were exposed 2 min, 15 min, 2 hours, and 8 hours after coating to a grayscale illuminated by 2-#2 blue photofloods approx. 15 inches from the gray scale. Incident light was 40 foot-candles. Plate 14 shows the 2 min. plate (Plate 14a), the 15 min. plate (Plate 14b), the 2-hour plate (Plate 14c), and the 8-hour plate (Plate 14d). To avoid any latent image fading, plate development was begun within 5 minutes after exposure.
The results indicated that the sensitivity of a Daguerreotype plate increases rapidly during the first 15 minutes after coating and reaches a plateau within 2 to 8 hours after the fuming process. The data confirms that the aged plates were slightly more than twice as sensitive to light as the freshly prepared plate.

[photolytic]

Congratulations all !
Unlike most I started with iodized plates and mercury developement.

I had never heard of Becquerel in those days.

Fuming was done in a wooden box containing a glass ashtray with an ounce of iodine crystals.
Plates were inserted in a small wooden drawer at one end of the box.
The exposure was 3 min at f/8 in an old Kodak Pony Premo glass plate camera.
Development by inspection was done in a wooden box shaped like an inverted pyramid
Inside was a small beaker containing a few drops of mercury.
Heated was done with an alcohol lamp.
The plate was not gilded and has never been sealed. Hence the tarnish.

[photolytic]

Half a mil (0.0005) of silver weighs less than half an ounce (0.417 oz) per square foot of surface.
You had just over half a square foot plated (0.5755 Sq ft).
That plater put less that a quarter oz (0.24oz) of silver on all nine plates,
It cost them $4 to $5 at the most.
They really took advantage of you.
Either your plater charged you a hanging fee of $40 per plate or he has a minimum charge of $400.
My plater only charges a fee of $30/12×18 sheet + a silver fee of $30/sheet for a 0.001 coating.

[photolytic]

Before Gerald Megan or Charlie Schreiner, Irving Pobboravsky did his definitive Study of Iodized Daguerreotype Plates in 1971. His report is not available on line but well worth reading if you can find a copy.

He studied the sensitivity of iodized silver plates through 3 color cycles using both Becquerel and mercury development.

On page 45 of his book he lists the relative Becquerel speeds of iodized coatings ranging in thickness from 15 to180 nanometers. Pobboravsky’s Becquerel plates were developed under a 500 watt 3200K lamp at a distance of 30 cm for only 20 min.

He reports that the maximum speed was for Becquerel plates with a 30nm yellow coating was ISO 0.0008. or “60 seconds at f/4.5 on a bright sunny day.

Plates with coatings thicker than 80-90nm (2nd yellow) up to 180nm (3rd yellow) showed no image after 20 minutes and were assigned a relative speeds of Zero. Subsequent Becquerel workers have successfully employed longer development times to develop more heavily coated plates.

[photolytic]

On my website you can view a lenticular stereo Daguerreotype print I made in March of 2003.

On the right side is a 5×7 lenticular stereo Daguerreotype laminated with a 40/lens per inch plastic lenticular screen.
On the left side is the 5×7 B&W lenticular transparency of an antique Swiss microscope, provided by David Burder, from which the Dag was contact printed.

[photolytic]

I haven’t been making colored Daguerreotypes lately but a few years ago I did some experiments on the effects of various copper and iron salts on heliochromes. In the Burder and Niepce de Saint-Victor process the plates are coated in a solution of ferric chloride and copper sulfate. I found that copper chloride, also worked to a limited degree. At least the silver chloride was formed on the surface.
Plates coated in iron chloride solutions tended to form more reddish flag images whereas plates coated in copper chloride solution formed fainter reds and blues.

Plates coated in a solution containing both ferric chloride and copper chloride together or both salts applied sequentially in separate solutions tended to reproduce the colors of a Kodak Q60 Target slide better than did a solution of ferric chloride alone. The Q60 Trans was very thin. Therfore the exposures required were only 20 min in direct sun The colors produced appear to depend upon the presence of water soluble Iron and copper salts trapped in the insoluble silver chloride matrix and can be washed out with water in 24 hours leaving the silver chloride behind.

Approximately 3-4 years ago I did make and keep 4×5 heliochromes prints of Burder’s high density Fruit bowl transparency. They were made by coating silver plates for 3 minutes in 3.0 or 4.5% FeCl3 solutions which also contained 2.2 or 2.6% CuSO4 respectively followed by a 5 second rinse in distilled water. Longer contacts with water both before and after exposure were avoided. Burder’s fruit bowl transparency was very dense. Therefore exposures of 12 hours in direct summer sun were required. Since then the plates have been kept in the dark in glass plate holders. except for brief periods of examination. They have shown very slight signs of fading.
However when the plates were fixed in a solution of sodium thiosulfate, the colors completely disappeared, leaving a positive Daguerreotype image.
I have images of all my heliochrome work but I was unable to attach them here.

[photolytic]

I’ve seem old stereo Dags made both ways, on a single plate or on two plates taped together. You can’t tell whether they used one exposure and then cut the plate or used two exposures. Those thin 19th Century plates were easy to cut with tin snips but cutting the thick engravers copper on most modern plates requires a band saw (which I have done). Frankly I think that having both stereo images on a single plate looks much better and the result is worth the effort in my opinion.
Don’t have a stereo camera? You can make both stereo images on a single 4×5 plate using the cha-cha method and a single lens graphic camera equipped with a shifting split back. These come up on EBay occasionally. The resulting plates can be easily mounted in one of Alan’s modern masher style cases as shown in the stereo section of this website and the stereo effect is quite stunning.

[photolytic]

All my stereo Dags were made using a version of the so called cha-cha method.
http://www.moderndags.com/stereo%20gallery.htm
When I used one of my two-lens stereo cameras, I would cover the lens on one side, shift the whole camera at least half an intraocular distance to the opposite side, and expose one side of the plate with the uncovered lens using the shutter. After completing the first exposure, I would cover the lens I had just used and uncover the lens on the opposite side of the camera. Then I would shift the camera at least one intraocular distance to the opposite side, and expose the remaining side of the plate. As you suggest all this had to be done before anything within the cameras field of view moved. While this may sound complicated you might note that I did not have to invert my camera as some stereo Daguerreotypists have reported doing.

[photolytic]

Many contemporary Daguerreotypists now use random orbital polishing.
This leaves a network of tiny multidirectional swirls which are almost invisible regardless of the orientation of the lighting.

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