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Li, you are right but don’t give up. High moisture content in the air is bad for Dags but it may also be high even when it is not raining. It is a good idea to get a humidity gage and record the humidity along with your other fuming data for each plate. Plates fumed with less iodine and bromine seem to be more moisture resistant.

Silver iodide is not hygroscopic but it is sometimes used to “seed” clouds to produce rain. The crystalline structure of silver iodide is similar to that of ice so it causes condensation of water in clouds which are supersaturated with moisture.

Heating the plate before fuming is also a good idea.

To prevent moisture damage, seal the freshly fumed plate in a plastic bag with silica gel or dry rite (sodium sulfate). After you expose the plate, put it back in the plastic bag until you are ready to develop it. If you expose the plate outside the house where it may be warmer,

Allow the plate to warm up to the outside temperature before you open the bag so the moisture in the hot humid air will not condense on the cooler plate.

As for the black spots, they may be caused by poor polishing which gets worse in high humidity.

During the polishing step the heat from the friction between the buff and the plate should be enough to heat up the plate. Charlie Schreiner recommends heating the plate during high speed buffing with wax rouge sticks to prevent polish build up on the plate.

If the plate is not heating up you may need to apply more polishing pressure

[photolytic]

Mike may be able to share some advantages of mixing the Iodine with silica gel but outside of keeping the moisture level lower in your fuming box I can’t name any. Fuming time will be longer. I’ve had my iodine crystals in the fuming box for 12 years and they still work great.

Unlike bromine liquid which is “anhydrous” (is that ok Josiah?); iodine won’t mix immediately with silica gel. You will have to wait until the solid crystals sublime so that the iodine vapor can penetrate the silica gel.

[photolytic]

Andy, Cyanoacrylate will bond Plexiglas and Teflon but it does not dissolve either one.

To form that kind of bond, usually referred to as a weld; you need an actual solvent for acrylics such as methylene chloride. Unfortunately Teflon does not dissolve in common solvents.

That is why you need to roughen the surface to create more area for a mechanical bond.

[photolytic]

Thanks for the excellent idea Andy.

While cheaper plastics have a distinct initial cost advantage over Teflon, the low coefficient of friction of Teflon should also be a considered. Cyanoacrylate gluing is an excellent idea but its long term adhesion to Teflon or even Plexiglas should be tested.

In planning a Daguerreian darkroom one should also consider how many Dags you plan to make before trading in your old 3G fuming box for the faster 4G model. You may fume several hundred or even several thousand Dags during your Daguerreian career.

Operating the sliding drawer on the fuming box puts a lot of wear on the plastic underside of the drawer. Eventually grooves will be worn in the plastic surface and the seal will be lost.

No plastic will hold up as well to this wear as well as glass. This is why many fuming box makers still use glass. My 14 year old glass lined boxes are still performing like they did several thousand plates ago.

[photolytic]

Some instructions in the resources section are varied and contradictory.

It appears you have misplaced the decimal point in your information.

Irving Pobboravsky recommends 15 grams of thiosulfate and 15 grams of sodium sulfite per liter.

The maximum solubility of bromine in water is 4.17 percent. (Not 47%).

Bromine to be mixed with silca gel or calcium hydroxide must be the dry type.

Once bromine is dissolved in water you can dilute it with more water for fuming.

You may find Gold chloride is available on EBay for less than 150 euros/gram.

Don’t gild every image you make. Only your best Dags deserve this final finishing step.

Gilding a whole plate requires less than 0.1gram of gold chloride or 15 euros worth.

[photolytic]

I’ll be in on Wednesday also.

It would be great for all of us to attend Kens talk at the Museum of Fine Arts on Thursday morning.

Don’t forget to register early for the Symposium talks too.

The society needs your support.

[photolytic]

Automatic control of the temp is not necessary.

For a person without technical knowledge

I’d suggest sticking with an alcohol lamp and a good themometer.

[photolytic]

Don’t use copper.

It reacts with mercury.

[photolytic]

Not enough Iodine. For faster fuming you need enough iodine to cover the bottom of the dish.

Your first fuming cycle may have exhausted the iodine vapor above the crystals.

You might try waiting several minutes before putting the plate back in the box for more fuming. That will allow the vapor to build up again. When the iodine vapor is restored it will react with the silver. The rate of the reaction of the iodine with the silver surface, which some are calling “uptake”, is actually a kind of corrosion of the silver surface. As such it is affected by the polish of the plate but is mostly dependant on the temperature and the iodine vapor concentration.

[photolytic]

Charlie Schreiner has some good plate fuming colors posted on his newdag.com site but here are a few of my own.

I fumed this plate about a year ago and kept in away from the light.

 

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[photolytic]

Dagwood,

Unless you forgot to put the iodine in the fuming box, your plates may be turning to the 2nd yellow after only one minute at 85F (30C). If you are not looking at the color of your plate frequently (10-20sec) the color may just be jumping from one cycle of yellow to the next.

I don’t think having too much light is the problem but rather not having the right color light.

Looking at the plate colors using a white colored light shining on a white surface is best.

Even with a white light on stray light from a red colored safelight makes judging the shifting plate colors more difficult as the colors look warmer (rosy).

The color changes during the bromine fuming are more subtle, shifting towards a rose to blue tint but not back to yellow again. The ultimate effect of bromine fuming is best judged after a second fuming with iodine.

[photolytic]

If you are using dry rouge or lampblack just keep using the same velvet until it become torn or worn. You can polish dozens of plates with it.

It actually works better as it accumulates more polishing agent in the nap of velvet.

I always keep one paddle or random orbital pad covered with clean velvet to remove residue from the plates. When one of the more heavily used rouge or lampblack polishers wears out, I replace it with the slightly dirty clean pad and make a new clean pad.

One yard of velvet lasts me for years that way.

In the long run you actually spend more on double-sided tape or buying premade plates vs. having your own copper plated with silver

[photolytic]

Only use flannel as a backing for velvet on the buffing paddle.

Unless you are using it to buff off old images flannel is too rough for polishing.

[photolytic]

Stop when you get that “beautiful finish”

Don’t use alcohol on the hand buff.

Use a dry buff with dry rouge, then lampblack, and finally no buffing agent.

[photolytic]

Hi Li,

Conservation clear is probably the same as museum glass, if by clear they mean colorless not transparency. Museum glass is made with low iron sand so it does not have the greenish blue tint of regular glass. The color is in the interior of the glass, not just a layer on the surface. Adding a layer on the glass surface can correct the apparent color but it does so by filtering out the color, so it also reduces the transpareny of the glass. If you look at the edge of a sheet of museum glass it will show no tint on the inside.

In 2008 my glass supplier in Chicago charged $950 for a 100 square foot case of museum glass cut to wholeplate size, but they charged less than $100 for a case of regular glass cut to the same size.

John

[photolytic]

Most of the responses seem to be focusing of the tape issue here so I’ll switch to glass.

The advice you received from the seller of photo framing supplies does not apply to Daguerreotypes.

While colorless museum glass is nice to use, UV protection is not necessary with Dags, because they are not faded by light, and low reflectance glass interferes with the reflection from the surface of the Dag plate, making the image harder to see.

[photolytic]

Better line this with epoxy.

Mercury reacts with Aluminum!!!

[photolytic]

I use a 2-stage rotary vane vacuum pump commonly used to evacuate cooling systems prior to adding new refrigerant.

http://cgi.ebay.com/JB-DV-142N-5-CFM-2-STAGE-1-2HP-VACUUM-PUMP-/290562964099?pt=BI_Pumps&hash=item43a6e6fa83

 

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[photolytic]

According to some the brightener make the silver plate more pourous but harder to polish.

There is no signifcant effect on silver content but some increase in sulfur from the brightener seems likely.

The flashes are 9600ws Speedotron 105 heads.

I have a 150mm Zenotar f2.8 lens but have not used it yet.

With a f3.5 lens only one 9600ws flash is enough to take a mercury Dag @ 1 meter.

However, it takes 6 or 8 such flashes to make a Becquerel Dag at 1 meter.

 

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[photolytic]

If no brightener is added the silver will bright when the coating is very thin (0.1 mil) but will become matte or cloudy white as the electroplating becomes thicker.

Polishing of the thicker coating will not make this dull silver coating bright enough for good Dags. There is also a third type of silver plating called semi-bright which is in between matte and bright. (less brightener)

 

 

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[photolytic]

I use bromine mixed with calcium hydroxide.

Bromine water is sometimes the only form of bromine available in some countries.

but water in any form in the fuming box can cause blue tones on the plate.

Bromine fuming not only makes the plates 60 times more sensitive, but when used in the proper ratio with iodine, it can also reduce excess contrast and solarization. Too much bromine can cause fog.

[photolytic]

Hi Máté,

Welcome to the confusing world of modern Daguerreotypy.

I say confusing because there are many ways to make Dag and even more rules about safety. Since you are just beginning, I would suggest that you first read more of the posts and articles in the resources section of this website to give you a running start.

First the Iodine: In the proper quantities, an essential element in the human diet to prevent goiter. Iodine tablets are widely used in Africa to disinfect polluted water. Works like chlorine to prevent cholera only far safer to handle.

The generally accepted method of handling Iodine is to keep it in your well sealed fuming box between uses. Transferring it in and out of the box is messy, and unless there is some risqué the box will break while you are transporting it, unnecessary.

If you have a good fuming box you will not smell or otherwise be exposed to iodine fumes while you are fuming plates.

Second Bromine: Bromine is now replacing chlorine to disinfect swimming pools. It is also present, as bromide salts, in the air above the Dead Sea, which many tourists visit for their health.

Daguerreotypists usually mix the liquid bromine with calcium hydroxide, silica gel or even water in a well ventilated area or better yet, outside. Then put this mixture in your fuming box and leave it there. Glasses and gloves are advisable and mask may be needed during mixing unless the ventilation is extremely good.

As with Iodine, the odor or exposure to bromine from a well constructed fuming box should be negligable during plate fuming.

Cold Mercury: Unlike the halogens, the once widely used medical applications of mercury for everything from skin rashes to syphilis are now in the dustbin of history.

First, familiarize yourself with the use of glass vacuum desiccators. You only have to pump out the air once each time you develop a plate. When the dessicator is sealed, the vacuum stays constant until you let the air back in.

The air you suck out contains the same low level of mercury as the air remaining in the dessicator, not more. If you are at all concerned about your fruits and vegetables, I recommend passing the discharged air from the pump through a coil of copper tubing or a bed of mossy zinc. The amount of discharge will be far less than from a fume hood which your neighbors should appreciate.

To develop at plate, I recommend a temperature of 20c and a vacuum of 50 to 75 torr for 2 hours.

Good Luck,

John Hurlock

[photolytic]

Excellent advice Rob, The gold solution keeps for years but thiosulfate is a weak reducing agent and reacts with the oxygen in the air to form sulfate. In time sulfate reducing bacteria can form hydrogen sulfide (rotten egg).

Filtering is a good idea too.

If the gold chloride/thiosulfate solution is too acidic (Ph 2-3), a bit of alkali (Kodak Balanced or dilute NaOH) can be added to raise the Ph to 4-5 for whiter highlights.

[photolytic]

The shiny silver spots on your plate are caused by droplets of liquid mercury falling on the plate from the top or sides of your mercury box. Periodically you need to wipe the inside of the mercury box to remove liquid mercury that has condensed there before it has a chance to fall on your plates. Before you fix your plates you can sometimes remove the mercury droplets from the plate by holding it vertically and banging it several times on the side of the mercury box. Due to their high surface tension, the mercury droplets usually do not wet surface of the plate and form the shiny spots until you put the plate in the fixer.

[photolytic]

I agree with Rob that placing a layer of cheese cloth on top of the iodine will lessen the tendency for rearrangement of the crystals when the box is moved. I haven’t personally used this method recently but I haven’t notice any increase in uneven fuming. I believe most of the uneven fuming is the result of variations in roughness of the plate surface due to insufficient polishing or areas of silver worn thin on older plates. Rough areas in the silver surface have a greater surface area, allowing the iodine fumes to react faster.

Because most of the distance between the iodine/cheesecloth layer at the bottom of the box and the plate drawer at the top of the box is filled with an air/iodine mixture, any movement of the box can still cause a temporary disturbance in the iodine vapor stratification. I always allow my fuming boxes to sit a few minutes after moving them from their normal storage area to my fuming table to allow the air/iodine mixture to reestablish equilibrium.

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