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Do not trust the bromine reagent bottles from Alfa Aesar!!!

After more than 4o years of using bromine obtained from Fisher Scientific, I decided to buy some from Alfa Aesar. Since I hadn’t quite finished up all the Fisher bromine, I left the Alfa Aesar Bromine sealed in its vermiculite filled tin shipping can for almost a year. Corrosion began to appear on the outside of the can so I decided to inspect the contents. Upon opening the can I discovered that the top of the plastic bottle cap had been eaten away by the bromine and vermiculite packing was saturated with bromine fumes. Luckily I had saved my old bromine bottle from Fisher and was able to transfer the new Bromine to the old bottle where it remains safely sealed after more than 5 years

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Irv, Do you still have access to the equipment that you used to measure the color sensitivity of AgI D-types for your thesis project? Edmund optics used to sell a calibrated color target transparency that contained the full spectrum of visible colors, all approximately the same density. As I recall it was over $1000 so I never was tempted to buy one. Presumabley one could place this target on a Dag plate, expose to a broad spectrum white light and measure the variations in density porportional to the spectral sensitivity of the plate. Ive done this using the Kodak Q60 color test chart but the colors it contains are not pure enough for a critical test.

 

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Irv,

Has anyone done similar experiments to measure the sensitivity of silver bromide or mixed silver iodide/bromide coatings on Daguerreotype plates? The reason I ask this is because of the findings of Skiadnikiowitz et al (Technical Univ. of Dresden) published in their article “The wet Collodion Process- A Scientific Approach” in the Oct 1998 issue of The Journal of Imaging Science and Technology. I believe you gave me this article Irv.

They reported that the spectral sensitivity range of wet collodion plates coated with an AgI: AgBr mixture was 383- 530nm (Max @440nm) whereas AgBr alone was 390-500nm (Max @ 450nm) and AgI alone was UV -437 nm (Max @ 420-425 nm) The net result of adding bromides was increased sensitivity in the green region of the spectrum but no measurable increase in photographic speed. Similar results were found by Eder in 1912 and by Schlutz-Sellack in 1871.

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Hi Alan,

I like contrast too. It is what gives Dags their eye-poping appeal.

Don’t give up you quest for it.

Solarization comes in many suttle forms for which the term solar may not seem appropriate.

Generally all bluish tints are caused by a superabundance of small image particles.

I noticed that in your portrait the tones in the lower half of the plate, containiing the white flowers and her lower arms, are warmer and lack any bluish overtones. I suggest that this part of the plate may have received slightly more bromine fuming due possibly to uneven buffing. A slight increase in overall bromine might have eliminated the bluish cast in the center of the plate.

I am a bit surprised that you are getting these bluish tones since the plate was galvanized.

Proponents of galvanizing have claimed that one of it’s benefits is the elimination of solarization and the formation of purer whites.

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Alan,

Nice portrait. Regarding the bluish cast, have you tried more bromine?

Extending the second iodine fuming after turning off all white lights (safelight only) will reduce contrast and solarization. This may reduce the plate speed slightly, so you might have to increase the exposure time when you do this.

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Alan, Is your UV meter reading incident light?

Can it also take a reading of the UV light reflected from your subject?

Maybe you should try a pinhole lens to capture UV on a Dag Plate.

Compare that to a lens shot at f/45 to f/60 to see if there is any difference.

I think Irv said he tried a pinhole camera once.

A quartz lens is an expensive alternative.

You can put this one on your Nikon for only $4500 USD.

http://jenoptik-inc.com/joomla/index.php?option=com_content&view=article&id=27&Itemid=40

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Corey, No color wheel but I’ve shot flowers with surpising results. Yellow seems to be the most difficult color. This Dag of a bright yelow sunflower (EV 15) required a 4 min exoosure @f4.7 on a mercury developed I/Br plate.

Yet some of the flowers around this bird bath were recorded as solarized blue after only a 10 second exposure @f/4.7.

 

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[photolytic]

I stressed the importance the keeping plates dry in my article but apparently with little success. All it took was one post by another Daguerreotypist that “one of the best Dags I ever made was taken in the rain” and all caution went out the window. If you carry a mirror (or bare Dag plate) in your cooler and it fogs up when you take it out and breath on it, you’re Dags are in trouble. Don’t put silca gel in the cooler. Instead put the desicator and the Dag in zip-lock or other re-sealable plastic bag and put the bag in the cooler. When it’s time to remove the bag from the cooler, let it warm up for 15-30 min before taking the Dag out of the bag. While the Dag is still cool, say below 20C, you have an hour of so before latent image fading becomes a problem so it’s better to ere on the high side and wait a little longer if you have stored the Dag at freezing temperatures (-10 to 0C). With practice you can accurately judge whether the Dag was cool enough by touching the back with your finger. For best results it should be just barely cool to the touch. Keep a series of Dags in individual bags and defrost them one at a time, storing the remaining Dags in the fridge. That way you can tell if the defrosting time was too long or too short and adjust the remaining Dag warm-ups accordingly.

The type of cooler doesn’t matter much. I have the thermoelectric type and it works quite well but will drain your car battery if you stop too long during the trip. For short trips in the winter, just keeping the windows open on the car is often sufficient if the temps are in the +10-+20 range. Remember not the put the Dag container in the sun. Especially if it is a black camera bag or the Dags will get much warmer than ambient temperature.

A UV meter may be a waste of money. Irving Pobboravsky measured the maximum Dag film sensitivity and found that it coincided with maximum light absorbance of the first yellow AgI coating color or 420nm.

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Larry, What you say is true only for Becquerel plates iodized to the first yellow color with a 30 nm coating. According to Irving Pobboravsky’s excellent thesis, which is posted in the resources selection, he found that Becquerel plates iodized to the second yellow color (110nm) are more than 16 times slower. He found the opposite to be true for mercury plates. Mercury developed plates with a 30nm coating (1st yellow) were found to be 6 times slower than Becquerel plates but mercury plates with a 110 nm coating (2nd yellow) were actually 4 times faster than Becquerel plates with that same coating.

Development Coating thickness Yellow Relative speed

Becquerel 30 nm 1st 100

Becquerel 110 nm 2nd 6

Mercury 30 nm 1st 18

Mercury 110 nm 2nd 25

My own measurements of the relative speed of mercury developed, iodized plates vs I/Br plates, which can be found in my article “The Light after the Bromine” in the resources section ,indicated that iodized plates were 60 times slower than I/Br plates.

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Hello Ken and Rob,

My Dags were delivered and signed for at the museum at 10:37AM Aug 27. The details mention a “payment received” which may refer to a customs payment.

I too opted for an insurance value under the limit of $2500, but my son who works for FedEx told me that “Artwork” is normally NOT covered because it is difficult to establish the true value of such items. The same holds true for UPS insurance.

The US shipping restrictions apply to goods valued at $5000 or more and are intended to control the shipment to foreign countries of certain kinds of software, electronics and parts that might have military value. Most ordinary consumer goods like photographs fall under the category EAR99. If you intend to ship only once, you can apply for a temporary license (TMP) but after Oct 2008 an EIN not a SSN is required to apply for one. FedEx’s help line told me that most of their offices have or can obtain the necessary paperwork to apply for a license in less than an hour.

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Hi Rob,

I just shipped 6 Dags to Bry-sur-Marne by Fedex on Saturday. They arrived in Paris at 8:09pm Monday and were cleared by French customs at 6:37pm (Paris time) Wednesday. The clearance process took >46 hours as opposed to less than 20 min when I have shipped Dags to buyers in Paris.

Best,

John Hurlock

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Hi Jon,

There is nothing wrong with wanting to print Dags from other photographs, so long as they are properly identified as prints. Both Ken Nelson and Jerry Spagnoli have mentioned the advantages of this technique and the technique of using contact printing has been addressed on this forum before. The contact prints or photograms of translucent objects on Daguerreotype plates produced by Adam Fuss are marvelous and world famous.

How come your customer didn’t want blue corrosion on the mat too?

Might I suggest that a to be had short cut to creating those spots found on bad images might be to sprinkle that sulfur powder on the trans before your print the Dag from it, thereby adding instant spots and corrosion in one quick step.

Seriously, the general public and the news media repeatedly reinforce the stereotype that all old photographs are grainy, spotted and out of focus, whereas the opposite is true of most Daguerreotypes. Well preserved and properly encased, the Daguerreoytpe has the potential to outlast most if not all other photographic images including digital ones.

Up until now it has been one of the missions of the Daguerreian Society to emphasize the exquisite beauty, extreme detail, and longevity of the Daguerreotype image. I propose this question to our modern Daguerreotypists. Do we want to abandon the noble cause of the Daguerreian Society and instead perpetuate the myth that Dags are worn out relics, ready for the trash bin, or do we want to support efforts to preserve and protect these valuable historical and cultural records? How about a show of hands here.

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Thanks for the credit Andy. I did study the effect of light during fuming in my article “The light after the Bromine” but I fully credited S.M.Barger and W.B.White for first publishing the effect of light during the fuming process on the speed of the Daguerreotype plate in their monumental work “The Daguerreotype Nineteenth-century Technology and Modern Science. Smithsonian Institution Press, Washington DC, 1991.”

As Irving mentioned, the effect of light appears to be due to the formation of free particles or clusters of silver atoms, which Barger refers to as “photolytic silver”, within the silver halide matrix. During mercury development of the plate, these free silver atoms serve as a reservoir of extra silver which can combine with the latent image silver giving the image greater density and increasing the apparent speed of the plate. The formation of photolytic silver by light seems to be confined to the bromine fuming stage. With the exception of hyper-sensitizing or latensification by light, which are essentially pre-development fogging processes to build up image density, extra light during the iodine fuming stage seems to have little effect of the speed of mercury or Becquerel developed plates.

Like the effect of bromine fuming itself, the effect of light during the process increases with increasing light exposure, then plateaus, and eventually declines if a significant portion of the silver bromide is irreversibly converted to silver metal and the bromine gas escapes after excess exposure to light. The more silver bromide initially present on the plate, the brighter the your examination light can be.

The reversibility of this process referred to by Irving was first disclosed by Percy and Shaw in their “Treatise on the Chemical Changes Produced by Solar Radiation” published by S.D. Humphrey, NY, 1852, pp 192-199. They observed that the sensitivity of Daguerreotype plates which had been exposed to light could be restored many times if the plates were exposed to the fumes of both bromine and iodine. While partial sensitivity can restored by more iodine fuming alone, no amount of iodine fuming can restore the lost silver bromide to the coating, hence the need for additional bromine fuming as well.

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Like any volatile chemicals, the rates of evaporation or sublimation iodine and bromine are proportional to the ambient temperature. Thus the concentration of vapors in your fuming box are proportional to the ambient temperature (or reciprocal temperature in degrees Kelvin Celsius + 273) in your darkroom. Due to the density of the vapors and the distance between the chemical and the Daguerreotype plate in the box, the actual vapor concentration is quite a bit lower than the theoretical concentration but it nonetheless bares the same proportionality to the temperature. The vapors in the attached illustration were sampled from the top level of the funing box using a syringe and analyzed via iodometric titration with thiosulfate.

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plate: quarter plate with 1mil fine silver on 16 gauge copper

iodine: 2nd yellow

lighting: outside at 9:00AM, EV 14

aperture: 5.0

exposure: 25 seconds

development: 3 hours

gilded: yes

 

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[photolytic]

Printings out papers are made with a mixture of silver chloride/silver nitrate not silver iodide. Silver chloride darkens more rapidly under the influence of light alone than does Bromide or Iodide.

Any metal with an electrochemical reactivity higher than that of silver (or gold) is capable of replacing the silver in a photographic image. We can find likely candidates in the periodic table of elements. http://richardbowles.tripod.com/chemistry/reactivity/reactivity.htm

Platinum, Palladium are likely candidates and have been used to make or tone photographic images before. Unfortunately, they are also expensive. Russia, where Mr. Bailun lives is a major producer of these rare metals and they might be cheaper there. Perhaps he would be willing to try some alternate Dag toning for us.

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There is one minor difference.

Printing out papers were (are) toned with gold before the fixing stage.

I doubt that would work with Dags, although some workers have reported that fixing Dags in a weak solution of hypo produces beautiful golden brown tones.

One suggestion that Ken Nelson first gave to me was be very selective about which of your Dags you decide to gild. Not only does this eliminate the more difficult job of buffing off bad gilded images, but it saves a lot of silver plates. A bad image is not going to be a perfect image after gilding so the best approach is often to make another attempt before you decide to gild. Inspecting the image after drying is the best way to do this because an underwater view of a Dag image tends to hide the flaws.

Whether you chose to use the tray method or the gilding stand method, I have found that the decision to gild or not to gild can often be delayed for several days, or even years, without affecting the result, so long as the image is protected from corrosion and abrasion.

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Random Orbital Buffer

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A more obvious solution to moisture on the buffed plate is heating the back of the plate with a hair dryer just before you put it in the iodine box.

To remove moisture from the iodine in the box Daguerreotypists used to place a small dish of freshly calcined (melted) Calcium chloride in the box each morning before starting operations. The CaCl2 will absorb the water but not iodine and liquefy. You can drive off the water by reheating this desiccant and use it again. Absorbing the iodine or bromine on silica gel will also keep your box dry but it isn’t as easy to regenerate when it becomes saturated with water.

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Are you still using that unlined wooden iodine fuming box shown on your website?

Iodine crystals will absorb moisture unless kept in an airtight container.

I’d advise lining that box with a small glass food container and your box lid with a sheet of glass or Teflon. If you can’t find a new liner box that fits, try garage sales.

Glass food containers were more popular before Tupper ware became available.

 

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Hi Andy,

The rubber bulb technique removes larger buffing residue but leaves some behind.

After step 18 have you tried buffing the plate with new clean buffing material?

Was there any discoloration on the buff?

I use a series of 3 clean buffs, the first two of which become quite dirty after a few plates.

After several plates, I replace the material on the first buff and shift it to last in the queue.

To conserve material, I use only ROB pads.

No need to change acrylic plastic mounting blocks between pads.

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Your website says you bond silver (foil) to the copper plate with solder (acid core?). Above you have said the silver is plated. This is a unique method but it seems to contradict what you have stated above. Is the final acid rinse necessary to provide a proper bonding or flux for the soldering process?

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Jon,

Most use mercury boxes made of cast iron or welded stainless steel which conducts heat very well. When the mercury is heated the box is also heated. This eliminates the need to heat the sides of the box, assuming it is well insulated.

Monitoring the temp near the top of the box allows the operator to determine when the box has reached operating temperature. Some add a little heating tape around the sides of the box to help the process along.

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Jon,

I first heard of it from Irving.

The top of the mercury box is where the action is.

The mercury fume concentration is proportional to the temperature (and pressure).

If the temp at the level of the plate isn’t high enough, the mercury concentration will be too low and development with take longer. Unless the box is heated or well insulated on the sides as well as the bottom, the mercury evaporated from the cup will condense on the sides before it reaches the plate. If the sides are not heated, the upper portion of the box (and the plate) must be warmed by refluxing the mercury fumes alone, rather like a double boiler in your kitchen.

I develop at room temperature in a vacuum chamber where the concentration of mercury fumes is the same top to bottom, so there is almost no tendency for the mercury fumes to stratify in the chamber

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I admire your courage in jumping into the making of large Dag plates. It is always a challenge, particularly with limited experience in making smaller plates. My advice would be to go back and experiment a bit more with smaller plates.

You have not provided enough information for a diagnosis of the problems you have seen.

A 20 min exposure may be too long or too short, depending upon plate fuming, lens aperture, lighting, or developing conditions.

Developing larger plates requires more mercury and a larger developing apparatus.

More time and higher temperatures may be needed to preheat the box so that the mercury fume concentration is high enough at the surface of the plate. Do you have temperature sensors at the bottom and top of your mercury box?

The plate colors you report could be due to iodine alone or a combination of iodine and bromine.

You mention using potassium bromide, presumably with sulfuric acid, to produce bromine for fuming. Have you checked to see that you have allowed enough time for the bromine fumes to reach the top of your fuming box? My latest bromine measurement of bromine fumes (8/12/08) was .000014 Eq/l or .00112 grams/l of Bromine at the top of the box or approximately twice the molar concentration of iodine fumes at the top of my iodine fuming box at 20C. This is several orders of magnitude less that predicted by the vapor pressure of liquid bromine but still sufficient to fume the plate in 10 seconds.

We hope to hear more of your work in the future.

[Author]

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