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Corrected file name

[photolytic]

In the Heliochrome process the images are printed out by the action of sunlight or other bright light. This takes a lot more energy than most forms of photography. Exposure times are similar to that of other printing out processes, such as salt prints, Albumen prints, or silver gelatin printing out paper prints. As such, the times are several hours long without a lens, similar to Becquerel development times.

To get sufficient color saturation the silver chloride layer must be thick and must contain traces of iron and copper.  In his process, Becquerel used electrolysis of sodium chloride to generate chlorine gas which corroded the silver surface. Niepce de st. Victor and Burder used a ferric chloride/copper sulfate solution. A solution of copper chloride will also work but the colors are not as vibrant. Neither process produced an image that could be fixed. In fact even washing the surface of a heliochrome with distilled water will remove the colors, which presumably are dependent on the presence of iron and copper salts in the silver chloride matrix.

Fixing the heliochrome with thiosulfate leaves behind a permanent positive silver image which looks like a B-Dag.

 

 

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While I wholeheartedly endorse the findings of Barger and White, I have certain  comments on the rendering of the colors on Becquerel Daguerreotypes. It is most important to distinguish between regular B-Dags, silver iodide coated plates developed by continuing exposure to light, and Daguereotype images printed out on silver chloride coated plates, both of which were disclosed by Edmond Becquerel.  The prismatic colors recorded on a silver chloride coated Dag plate by Becquerel are the earliest examples of “permanent” color photography which are still visible after 150 years.

I have seen most of the colors mentioned on unfixed mercury developed daguerreotypes as well. For the most part the colors disappear when the Daguerreotypes are fixed.  One can assume from this that the colors are produce by the refraction of light within the silver halide coating.

Like the standing waves which produce the colors on Lippmann plates, such colors are highly dependent upon the distance between the refracting particles. In the case of Daguerreotype plates, these distances change radically when the silver halide is removed from the plate.

Becquerel was not the first 19th Century scientist to observe what is now sometimes referred to a natural color photography.  In 1840 John Herschel reported that he saw the same sorts of colors, as later reported by Becquerel, when he exposed paper coated with silver chloride to sunlight through a prism. He saw the same colors, though less distinct, with silver bromide. With silver iodide he saw complimentary colors. 

Herein lies the caveat. While unfixed silver iodide coated Dag plates appear to record colors, they are not necessarily true to the original colors of the exposing light.  My attempts to use the colors on silver iodide/bromide daguerreotypes plates to produce anaglyphic stereo images have not been successful, whereas similar attempts using silver chloride coated Heliochrome plates reported by Burder in his 2002-2003 Daguerreain annual article worked, “,just”.

 

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[photolytic]

Hi Bing,

Yes, Iodine and Bromine will eat though the wood.

You should have used a Teflon sheet without a cut out to seal the top of the glass tray.

Sealing just the rim as you have done will not prevent the fumes from seeping into the wood.

Eventually, after several years, the wood will have absorbed enough iodine to fume the plates without any iodine crystals in the glass tray.

Do you plan to add a screw and a pressure plate at the top to apply pressure against the rim of the tray to improve the seal?

After grinding the top of the tray flat, a bit of high vacuum silcone grease on the rim would also improve the seal.

The box looks great though.

John

 

[photolytic]

Most of your first plate is very good.

What are the times and temperatures for the fuming?

Bromine may be too long but without times I can not tell.

Divide the fuming time into several 2 second intervals, rotating the plate 180 degrees each time to prevent fuming one side of the plate longer that the other.  Because it takes about 1 second to pull out the slide or drawer the first half of the plate to be fumed receives a longer fuming time than the last half of the plate.

Try  masking parts of the plate with glass or plastic during bromine fuming and using different bromine times in each masked area.

That way you can tell which bromine fume time is the best.

Keep up the good work.

John

Second iodine should be about half as long as the first iodine.

You should do part of the second iodine (5sec) in white light.

You can better judge whether the bromine has been too long by examining the plate after half of the second iodine funing.

At his stage the color should still be rose or lavender but not blue or green.

 

Only about 2sec in dark (safelight) is needed to erase the effects of earlier light exposure.

 

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Charlie’s advice on newdags.com is good. Treat the plates like food.

The sensitivity of coated plates will last longer if they are kept cool, but spots may develop if they are not kept dry too. Use silica gel!

After the exposure Bakody’s advice to develop soon is also good.

If lasting, strong, sunlight is not available soon after exposure, get a 500w halogen work light.

Place the light about 30 to 40 cm from the plate which is covered with rubylith and start developing within an hour after exposure.

You can not substitute CFL light bulbs as the color they emit does not contain the same frequencies as incandesent bulbs and will fog the plates. Developing BDags requires both red and infrared light for the best tones without fog.

Rubylith can not create red light. It can only filter out the non-red part of the spectrum from the source of the light.

Development should be complete in about 2-3 hours giving you neutral (not blue) tones.

If more time between exposure and development is allowed the image may appear underexposed (bluish) unless you increase the developing time.  Longer camera exposures may also be required to compensate for latent image fading.

 

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Irv,

Reliable always uses x-ray Flourescence for silver thickness but I specifically request that they not use pin-holing anyway just to be sure.

Due to a dog bone effect, the silver plate is always thiner in the center of the sheet and thicker at the edges.

I request a minimum of 0.75 um in the center which gives me an average just over 1mil per sheet.

I hope that answers your question.

John

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HI Irv,

I have Reliable plate 12 x 18 inch sheets because that is the largest size I can cut up with my band saw.

Silver plate thickenss may vary slightly from sheet to sheet but it is alway close to the 1 mil average I request.

Brightness is usually good over the entire area with some slight film near the edges which buffs off easily.

John

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A matt finish is not necessary for adhesion of the silver plate.

Most platers use an initial high current “strike” coating of silver to insure good adhesion before the main silver electroplating.

It’s good insurance to keep the plastic film on the polished copper to protect it from damage during transport to the plater.

If you send a large copper sheet to the plater only two hanging holes (1/16) are needed.

After the plating only two of your plates will have holes and there will be no waste at the edges between plates.

If you plan your cuts carefully you can usually avoid the corner holes completely and sacrifice only two small quarter inch squares of silver plate per sheet.

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Yes Marizu,

I have used them for 14 years.

Have the plater put on at least 12.5um (half a mil) of bright silver plating.  25um is even better.

Dull silver plate, used for electrical circuits, or semi-bright silver plate will not polished up correctly.

To save silver put a layer of platers tape, available at MacMaster Carr, on the unpolished side of the copper.

Make sure your plater uses a non-destructive method, such as xray flouresence, to measure the plating so there are no holes in the silver.

If you want to check your silver platers accuracy, weigh the polished copper before and after plating. Correct for the removed plastic film.

Your plater will probably have a minimum charge and will charge a per piece fee for hanging the copper in the bath plus a charge for the silver used.  Thus larger sheets may end up costing you less to plate for the same area but you will have to cut them to size later.

The best of luck

John

[photolytic]

The tones are wonderful.

My wife has water lilies too but it is getting too cold for them to bloom here.

I think that you are ready to add bromine to your fuming.

For solarization and high contrast, keep the bromine to a minimum.

The fuming time will depend upon how much bromine is in your quick but 8seconds @ 20C is usually enough. You should see a color change (rose-violet) after the second iodine fuming.

Best of luck, John

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I like the slightly brown colors on your water lily Dag.

Is that cold or hot mercury developed?

Most of my experience with iodized plates is with Becquerel development.

I found that Iodizing to a magenta color (40=60second@20C) or a blue color (70-90seconds) worked faster than iodizing to a yellow-rose color (15-20 seconds), but I was not looking for solarization. Your best conditions to create blue colors are to increase the exposure and shortening the developing time.

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Once you get a mercury spot on a plate it requires a double buffing to remove all traces of the mercury residue. Before that happens these traces of mercury leave an area that is less sensitive. One technique to remove traces of mercury is to "burn the plate". You can do this by heating it in an old electric frying pan to 150C to evaporate all traces of mercury before the final polishing. This must be done outdoors to safely disperse any mercury fumes coming from the plate.

[photolytic]

The spot is caused by a large mercury droplet falling on the plate. This can happen with hot mercury also. Movement of the desiccator during development can be the cause.

Always face the plate down so mercury cannot fall onto it from the top of the desiccator. Do not put the plate in contact with the mercury bowl. When you pour the mercury out of the bowl it may leave tiny droplets of Hg on the rim of the bowl. I have developed both large and small plates in the same large desiccator and have not seen much difference in development time.

5.5 hours at 17C seems too long but the plate does not look overdeveloped.

[photolytic]

You may also have to increase the exposure time. Remember that the speed of a mercury developed iodized plate is the same as a Becquerel plate which is approximately 60 times slower than an iodine/bromine plate so just substitute minutes for seconds and you will have the correct exposure.

As for the mercury temp, I would not let it cool below 15C. Mercury vapor pressure at 10C is 0.00049mmHg or approx 40% of the Hg's vapor pressure (0.001201mmHg) at 20C. To compensate for this you would have to increase your development time by about 2.5x or 5hrs at 27in Hg.

You could also increase your vacuum to 28 to 29 inches of hg

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In my previous post I said “Mercury weighs 13.5 grams/ml so 100 ml is only 7.4ml.”

Of course I should have said 100grams of mercury is only 7.4ml.

I hope I didn’t mislead anybody by this typo.

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The specific gravity (density) of any chemical is easy to lookup, either on Google or in any chemical handbook.

Mercury weighs 13.5 grams/ml so 100 ml is only 7.4ml. This is hardly enough to cover the bottom of a small dish.

Bromine weighs 2.93 gm/ml so 100ml would be about 34ml. 100grams of bromine is enough for a year or two of Dag making, but considering the delivery costs, 250grams (85ml) might save you money in the long run.

My recommendation would be to start by trying cold mercury development of plates without bromine until you work out all the variables (temp, Vacuum, time) and then add bromine to the mix.

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The hand vacuum pump found in auto parts stores does not have enought capacity to evacuate a bell jar. A water aspirator sold in chemical supply houses is a cheap alternative if water consumpion is no problem. A small rotary vacumm pump used by refrigerator repairmen is the best option. You can by a used one on EBay or get a new one from artist supply houses like Danial Smith.

[photolytic]

Hello Dafna,

I started out using a polycarbonate desiccator but it didn’t hold a constant vacuum. I tried re-evacuating during development and applying some vacuum grease to the rubber gasket but nothing worked very well. Often the plates came out blue due to under developing.

Yes you can develop single iodide plates with cold mercury.

The images come out very strong with high contrast.

This is probably a good place to start before you try using bromine again.

Concentrate on your developing technique first then gradually add bromine to the process.

[photolytic]

According to this report mercury boxes designed to hold “2 or more plates” were available as early as 1853.

http://www.earlyphotography.co.uk/site/entry_H1.html

Knight’s catalogue of 1853 shows a similar box to this example described as the ‘Improved Mercury Box’, however it is fitted with a slide to view the plate rather than a hinged flap. The cost was £1.9.0 for a model without a thermometer. Also shown is a model where the exposed plate is attached to the slanted lid of the box, the lid has to be raised to see the progress of development (this is also illustrated in the ‘Barger, White, Daguerreotype’ book). A further type where the plate is held vertically is shown and described as by Bingham (presumably R.J. Bingham). In Willats’s ‘Practical Hints’ a box is illustrated able to take two or more plates next to each other, the plate holders rest against the outside of the box and have short handles attached to lift them.

Presumably these could be used to develop a pair of stereo sixth plates, exposed simultaneously in a 2 lens stereo camera.

[photolytic]

Rob you are correct up to a point but your last claim that Dags “are always developed one at a time” only applies to most 19th Century Daguerreotypists. If you read my 1998 article “Warming up to Cold Mercury”, in the resources section, you will see that several Dags can be developed at a time in a vacuum desiccator with a mult-slotted holder. Many B-Daggists also develop more than one Dag at a time since the developing process takes several hours for each plate. Too long to wait for the results of the first one before trying another shot.

[photolytic]

High Dafna,

Things to try.

Reduce the bromine fuming level.

Mask the plate and try several bromine times on a single plate.

Use less developing time.

Inspect with directional red light during developing.

Too much can fog the plate so use caution.

Best to keep plates out of any light during the developing process.

Check for worn areas on your plates.

Plates should appear evenly coated during the final inspection during fuming.

Ghost images indicate incomplete removel of previous images.

Good luck, John

[photolytic]

Judging by the colors it looks like you have at least 3 cycles of iodide on one plate.

That is a lot more than one would expect from uneven polishing. Still it’s an important factor.

Is the iodine distributed evenly in the tray at the bottom of the box? Perhaps you titled it just before fuming. Or as Bakody advised you should wait a while (several hours) after charging the iodine to allow the fumes to distribute evenly across the surface of the plate. Check the plate frequently during fuming and rotate the plate to compensate for unevenness in the iodine fumes. Your box should be 5 to 8 cm deep to allow plenty of room for iodine fume distribution.

The distance between the iodine and the plate is more important than the amount of iodine in the box. The concentration of iodine fumes diminishes sharply with the distance from the crystals because iodine fumes are 8.8 times heavier than air. See post of 5 July 5 2011.

 

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Perhaps you have read my article on preserving the latent image in Dags. While the article deals with mercury Dags, certain similarities exist. Like film you should not store Dag plates either before or especially after exposure at high temperature (like your car). A quote from the artivle below:

 

If the daguerreian practices under hot and/or humid conditions, the latent image may not

last more than an hour unless more extensive preservation conditions are employed.

Rapid cooling or freezing of the exposed plate, even in a recloseable plastic bag, before

the desiccant has absorbed the moisture therein will frequently cause moisture damage to

the image. Under these conditions, quickly removing the moisture-laden air from the bag

containing the plate has been shown to reduce damage and improve image quality.

 

IMAGE LIFE TEMPERATURE HUMIDITY CONTAINER

15 MINUTES 86F 30C 50% PLATE HOLDER

1 HOUR 68F 20C 30 TO 90% RESEALABLE BAG

24 HOUR 68F 20C 20 TO 30 % RESEALABLE BAG

5 TO 10DAYS 32F 0C 20 TO 30% RESEALABLE BAG

5 TO 10DAYS 32F 0C 20 TO 50% EVACUATED BAG

1-3 WEEKS 0F -18C 20 TO 50% EVACUATED BAG

 

EQUIPMENT FOR PRESERVING THE DAGUERREOTYPE LATENT IMAGE

The easiest method appears to be to seal the plates in their holder in a recloseable plastic

bag, together with a small amount of silica gel or calcium sulfate (DRIERITE®) desiccant, and

store the bag in a bucket of ice water.

One disadvantage of this method is that sufficient time must be allowed for the moisture

trapped in the bag to be absorbed by the desiccant before the plate is cooled to avoid

condensation within the bag.

More rapid removal of moisture and shorter plate thawing times can be achieved by using

a commercially available vacuum-sealing device such as the Tilia Inc. Foodsaver®

system. The disadvantages of this technique are the added equipment required and the

reliance on an electrical power source.

Tilia’s Foodsaver BagVac® appliance is available from Wal-Mart for less than $100

The BagVac® is capable of evacuating approximately 2/3rds of the air (i.e., 250 torr) and

then heat–sealing a plate holder containing a Daguerreotype plate in a heavy walled

plastic bag in less than a minute.

 

Unexposed Dag plates will keep for a day or 2 in the refrigerator if you seal them in a plastic bag with dessicant In a vaccum sealed bag plates will keep for several days in a small cooler with frozen gel packs.

 

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[photolytic]

Dafna,

Good progress. Try blowing the dust spots off the plate with one of those dust blaster rubber bulbs. Another technique is to invert the plate and rub it polished side down on a clean buffing paddle to wipe the dust particle off before fuming.

All the best,

John

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