[dagist]

A precaution for anyone building or installing a fume hood.

It is important that your fume hood’s exhaust fan is mounted OUTSIDE your building (drawing the air out instead of pushing it out).

If no outside solution is feasible/practical, the fan can be carefully mounted into a wall of your work space that vents directly outside (without any ductwork), but the entire fan must be contained WITHIN the fume hood itself. This set-up is not ideal and does have some risk because dangerous fumes might get pushed into the space between your interior and exterior walls (where you cut the hole in your wall for the fan), thus finding their way back into your work space.

Never should your fan be mounted on top of your fume hood (sitting in the same environment that you breathe in), even if it is directly mounted to a wall that vents outside.

The reason for mounting your fan outside, is so that the entire fume hood exhaust system has a negative pressure within all of its components (including all ductwork) until it reaches the exterior of your building where it can then be safely exhausted into the atmosphere. All exhaust system ductwork within your work space must contain a negative pressure, which assures that no fumes can ever escape into your working environment because the fumes are being sucked out, not pushed out.

Mercury fumes aren’t entirely odorless (they can be smelled/detected in large enough concentrations), and an improperly installed exhaust fan could release enough low concentration (odorless) mercury fumes into your work environment that you would be slowly harming/killing yourself without ever knowing it.

Don’t let this information scare you away from making daguerreotypes, just take the proper precautions (mount your fan outside) and you will be able to safely practice the most amazingly life-like image-making-process photography has ever developed…..the daguerreotype.

Daguerreian Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Festus,

As you begin your gilding experiments, you may wish to save your used gilding solution (I do), so that one day you can attempt to reclaim the preciously-expensive unused gold chloride from it. There is a process by which you can retrieve any unused gold from the solution. I now have a couple gallons worth of solution, awaiting my first attempt at reclamation. It involves purchasing additional chemicals (mossy zinc, for one) and I have yet to attempt the somewhat complicated process. Another project for another day.

I can’t say whether or not it is cost effective, because I really have no idea how much gold is reclaimable. Has anyone else attempted to reclaim their gold?

Good Luck,

Rob McElroy

Buffalo, NY

[dagist]

Festus,

I use a general-purpose laboratory filter paper. Whatman is one of the most popular manufacturers here in the US. I use a 20-year-old box of their Grade 40 ashless paper, for no other reason than I had a box laying around from an estate sale purchase many years ago. It is a classic paper for general purpose filtering with a medium flow rate and retention. It works great for me.

Whether a paper with a faster flow rate and less retention would be just as effective for gilding solution filtering, I don’t know. Maybe one of the chemistry experts among us can share their filter paper knowledge.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

For All,

I just discovered this three-minute review and interview (in French from TV14) of the Bry-sur-Marne exhibit – showing the exhibit space, various close-ups of the daguerreotypes, and Jerry Spagnoli doing his daguerreotype demonstration. Is someone willing to translate the interview into English and post the text for the non-French-speaking among us to read?

http://www.bry94.fr/bry/2704.htm

If anyone has discovered any additional reviews (in print or in video form) can you please post the links to them.

Thanks,

Rob McElroy

Buffalo, NY

[dagist]

Festus said, “Add A to B, but DO NOT add B to A, as this will ruin the solution. Whaaat? Is there some magic to making this?”

The rule that you must always remember when mixing your working solution of gold chloride is to ALWAYS pour the gold solution into the sodium thiosulfate solution. Do NOT do it the other way around, or you will risk a black precipitate forming in your solution which will make the solution unusable until you remove the precipitate. Pour the gold into the sodium thiosulfate quickly but gently and then agitate gently to make sure it is mixed thoroughly. It is also wise to filter your mixed solution before using it.

If you accidentally do pour it together the wrong way and get the black precipitate, the gold chloride solution can be saved by mixing some common table salt into the solution and letting it sit overnight. A teaspoon of salt should be enough to clear the precipitate from 100ml of gold chloride.

Good luck with your gilding and remember to heat the plate as evenly as possible. Don’t let any part of the plate cool down during gilding (especially the perimeter), otherwise you will get visible tide-lines (swirls) on the plate where the gilding solution hasn’t acted on the image uniformly.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Ron F. observed “Modern plates may have less silver on them, in which case you would not be able to repolish them as many times.”

It turns out that modern plates usually have much more silver on them than vintage plates, not less. Theoretically, you can reuse modern plates many more times than vintage ones. Your polishing technique will determine how many reuses you will get before the copper starts to show through.

Back in 1999, I made silver thickness measurements on both vintage and modern plates which showed that vintage plates usually have only about 10% of the thickness of silver that modern plates do. It of course depends on how much silver you have asked your electroplater to put on your modern plates. I used to ask for 1 mil of silver but now only ask for a half mil. Here are the silver thickness measurements taken from the center of eight different plates. The plating process will often plate more silver towards the edges of your plate than in the center, hence my .000851 measurement below was just under a mil for the center while the edges were just over a mil.

.000056″ 1850s plate #2

.000071″ 1850s plate #1

.000095″ Theis Plating–Ken Nelson

.000192″ Pierre Plating–Mark Kessel

.000202″ Pierre Plating #2–Mark Kessel

.000261″ Theis Plating–Tom Young

.000846″ Metal Finishing Technologies–Charlie Schreiner

.000851″ Buffalo Plater–Rob McElroy

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

For All,

There is currently a tour (10:10AM EST 9/20/2009) being given of Daguerre’s diorama. There is a live-feed camera in the room and we may possibly be able to see some of our daguerreian friends when they let them examine it a little closer. Here’s the link to it.

http://81.252.98.33:6001/local/viewer/cam1_popup_lv.html

And of course, all of us who couldn’t attend the exhibit in Bry-sur-Marne – are anxuosly awaiting some first-hand reports.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

For All,

Here is a link to a video review of the Bry-sur-Marne exhibit. It’s in French, and there are lots of close-ups of the daguerreotypes (none of mine unfortunately) and the exhibit space, with Marc discussing the process and exhibition.

http://culturebox.france3.fr/all/14800/Des-daguerr%E9otypes-contemporains-expos%E9s-%E0-Bry-sur-Marne/#/all/14800/Des_daguerr%E9otypes_contemporains_expos%E9s_%E0_Bry-sur-Marne

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

If anyone still needs to ship their daguerreotypes to France, the good news is that Fed Ex delivered my daguerreotypes today 8/28, only two days after I shipped them from Buffalo, NY. There were no hold-ups in Customs, and no duty had to paid by the museum to receive them.

Marc Keuren also said that he (or someone) will take photos of the exhibition so that we (all of us who cannot attend in person) can “…appreciate the atmosphere of the Exhibit.” The catalog is still being worked-on and is not going to be ready until the end of the exhibit.

Thank you Marc, for undertaking such a large and challenging project. I wish you much success. Please let us know when there are any reviews of the exhibit posted on-line, so that we might read them.

Cheers,

Rob

[dagist]

Ken and John,

Thanks for the info. After more research into the ATA carnet, I found out that it costs over $200.00 to get one (properly prepared by companies that specialize in doing them correctly) and that it would take several days to get it back in the mail (exorbitant rush charges were of course an option). Obtaining and utilizing a carnet is the proper way to import items temporarily into one of the 75 countries that honor them, but Fed Ex and UPS won’t handle them. Only DHL will process a shipment using a carnet if you have already obtained one, and they will also prepare one for you for a $75.00 charge.

Because the DHL telephone rep knew nothing about the $75.00 carnet preparation service they offer, other than how much it cost, I couldn’t trust that they would do it properly, so I opted to ship my package using Fed Ex like you guys did, in the hope that the museum wouldn’t have to pay the approximately $150.00 in duty that would be required if the six d’types were being permanently imported into France. I only insured them for $600.00, to avoid the US export documents required for items worth over $2,500.00, and, as John mentioned, because Fed Ex would probably not honor a claim much higher if the package was lost, damaged or stolen.

The only other way around the duty would be if the museum uses a Customs broker who files a Temporary Import Bond (TIB), which is a guarantee that the items will be returned to their originating country after a temporary stay. Hopefully that is what they are doing, but Marc never said so, so I don’t know.

I shipped my d’types yesterday (clearly marked “temporary import for exhibition”). Their expected delivery date is tomorrow (8/28). We’ll see what happens.

Cheers,

Rob

[dagist]

Has anyone from the US been successful in shipping their daguerreotypes to the exhibit in France using a document called an ATA Carnet which is the form that is used when you ship goods to another country for only a temporary term (such as items for repair, or in this case “goods for exhibition or display”) and which will be returning to their country of origin after a specified period of time?

This type of shipment eliminates any of the usual Customs duties that are applied to imported goods, but often requires the use/hiring of a Customs broker in the country where you are sending the items (France in this case), who must arrange for a Temporary Import Bond (TIB) in order for Customs to clear the items for delivery. The bond (similar to an insurance policy) essentially guarantees that the goods will be shipped back to their country of origin.

The ATA (Admission Temporaire) Carnet is defined on DHL’s website as, “A customs document permitting the holder to carry or send merchandise temporarily into certain foreign countries (for display, demonstration or similar purposes) without paying duties or posting bonds. All of the goods traveling under a Carnet must be returned to the origin country to avoid penalties. The most common type of carnet, the “ATA Carnet”, is accepted in more than 40 countries.”

Neither Fed Ex, UPS, or the US Postal Service will handle/process the ATA Carnet form, and from my research today, it seems that only DHL will process a package through French Customs using the ATA Carnet, and then deliver the package once it has cleared Customs.

Fed Ex said that the recipient of the package would have to arrange for a Customs Broker in France to post the required Temporary Import Bond (TIB) in order to get the package through Customs. Fed Ex would then deliver it, but only if asked-to by the broker or recipient of the package.

This appears to leave only DHL as a shipping option, but Marc Kereun asked me not to use DHL, stating, “Please could you avoid DHL, because its services don’t make ‘provisory importation’, only definitive importation with TVA , taxes (5%) to pay. Fedex, Mail or others are best to use.”

So, I’m in a quandary, and looking for a more definitive answer from anyone who may have discovered more options than I have.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

With bromine, you must be very conscious of what kind of plastic it gets near. Last year I traded some mercury for bromine with a fellow daguerreotypist and the bromine was given to me in a dark-brown glass bottle that once contained darkroom print toner (I think it was Edwal, if I remember correctly). The bottle had a common hard-plastic screw-on top. Everything seemed fine, until about a month later when I smelled bromine in my darkroom and realized that the bromine fumes had dissolved the hard-plastic top into a pile of goo.

The lesson learned was that bromine should ONLY be stored in and around a material that it won’t/can’t dissolve. Andy Stockton’s link at the top of this thread describes polytetrafluoroethylene (PTFE) as the only plastic rated “excellent” for chemical resistance to bromine. Polyvinylchloride (PVC) gets a rating of “good” and everything else is either “fair” or not recommended. My bromine is now stored in the original Baker Scientific dark-brown glass bottle I originally purchased it in 11 years ago. The screw-on cap has an inner liner that I presume may be PTFE.

Be careful…….very careful with bromine. If you accidentally dropped a bottle, you would have only seconds to clear the room before the painfully acrid fumes would begin to burn your lungs with every breath.

With the utmost of bromine respect,

Rob McElroy

Buffalo, NY

[dagist]

Here’s a recent 4″x5″ daguerreotype I have submitted for consideration. I will also be submitting additional new images in the next few weeks.

 

©Rob McElroy 2009 All Rights Reserved

 

 

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[dagist]

Larry,

What you had in your hands (and should have purchased) was a daguerreotype with a rarely seen Isenring background, named after the inventor of the process Johan Baptist Isenring, who invented this method of coloring daguerreotypes in the mid 1840s. You were correct in assuming that a stencil was used, because the background was added after the daguerreotype was processed.

The process worked like this. A piece of glass was held in place over the daguerreotype and the area to be masked-out was carefully painted on the glass. This image was then traced onto a suitable piece of tracing paper, and the area that was not to be colored by the process was cut-out. This cut-out was carefully laid on top of the bare daguerreotype to protect the areas that were not to be colored. The daguerreotype was then carefully slid into a box containing very fine particles of finely ground minerals of various colors. The box was shaken-up prior to inserting the daguerreotype, and the finest particles would then settle on the plate. It’s essentially a dusting process. The plate was removed from the dusting box (a name I just made up) and the cut-out (covering the primary subject) was then carefully removed, leaving the back ground evenly coated with the fine dusting of minerals.

If you examine an Isenring background with a magnifier, you will see multi-colored particles (grains), which, because of their extremely small size, can’t be individually differentiated with the naked eye. They thus form an overall tonality to the background which can look warm or cold depending on the combination of minerals. The background also tends to shimmer when viewed in certain types of light.

Because of their rarity, daguerreotypes with Isenring backgrounds are quite desirable and valuable to collectors, photo historians and photo conservators. I have only one in my study collection, and have many times turned down offers from people who wanted to buy it.

Regards,

Rob McElroy

Buffalo, NY

[dagist]

Ken,

Mallinckrodt Baker sells bromine and they are located an hour and a half north of Phily in Phillipsburg, NJ. One liter is $49.85. Not sure if it is stocked at that location so calling ahead is vital. Also, chemical companies (as you know) will not sell directly to individuals. You must be a company or an educational institution to purchase from them.

Here’s a link to their contact page:

http://www.mallbaker.com/contact/

There’s a search field in the upper right hand corner of the page, and if you change the default to “Products” instead of “Site” and then search for bromine, you will find it.

I don’t use bromine water, but isn’t it also feasible to find some at a swimming pool supply store? It won’t be reagent grade (the farthest thing from it probably) but it might also work. And anyone can buy pool supplies.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Andy,

Thanks for the compliments of my images.

Even though my own daguerreotypes are listed for sale in my eBay Store, my personal feeling is that eBay is not a good place to sell contemporary daguerreotypes. You can get some attention and exposure by using eBay as a marketing tool, but don’t expect many sales because there just aren’t very many collectors interested in buying a contemporary “process,” simply for the sake of the process, no matter how difficult the images are to produce. Collectors of vintage images, on the other hand, do often collect a “process” such as daguerreotypes, ambrotypes, tintypes, salt prints, etc. but most of them have little interest in contemporary work.

The photographic art world is another area that has very few contemporary daguerreotype collectors, although I’m hoping that will change. In this arena, the “process” takes a back seat to who you are (how recognized an artist you are) and what it is you are trying to convey or communicate with your art.

The contemporary daguerreotype is slowly beginning to be recognized as a medium unique unto itself and capable of imagery unlike any other in the world. It is now time for daguerreotypists to produce images that will compel the art world to stand up and take notice. Selling contemporary daguerreotypes will then become a lot easier.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Walter et. al,

What lenses grace these contemporary image makers? It would be useful to know the lens’s maker, focal length and maximum aperture, as well as how large an image circle the lens can produce before significant fall-off occurs on the ground glass. The camera manufacturer’s name and the camera’s format would also be helpful, along with the size of the final image if it is different than the camera’s format.

Many of us cobble together parts from several different manufacturers in order to achieve our daguerreian image-making goals.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Nick,

I agree with John that brush plating should not be considered a viable alternative to tank plating for the purpose of producing a daguerreotype plate. It is not designed as a process for applying an evenly distributed coating of silver across a large flat area, and it will most likely result in an unusable daguerreotype surface which is too thin, mottled or striated in its appearance.

It is a well established fact (ask any professional electroplater) that cyanide plating (as opposed to the cyanide-free alternatives) is the preferred method of electroplating if you want consistent plating results that will adhere properly to the substrate (copper in this case) and provide an evenly plated surface to your required thickness. The silver surface on an electroplated piece of copper is actually grown (think of it as layers that are gradually building up on top of each other) during its time in the plating bath and many factors can affect how the surface looks when it comes out. The porosity of the electroplated silver is also an issue, as well as how evenly it plates at the chosen current level. Brighteners used in the plating bath are also a concern and all these factors contribute to how easy or hard the silver surface is to polish after it’s finished.

As I said in a different post, silver plating is an art unto itself and many factors need to be precisely controlled in order to achieve consistent daguerreotype-quality results.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Jon,

The most important consideration with lenses is speed; the faster the better. A lens that can put f/2.8 or f/4.0 light on your plate is what you want to find if you are making daguerreotypes 4″ x 5″ or larger, and especially if you want to shoot people. If you make smaller images, even faster lenses are available. The lens’s speed isn’t really an issue though, if all you want to make are landscapes and still-lifes, where your subject isn’t moving.

Whether you use a vintage brass lens from the 1850s, 1890s or a modern lens from the 1990s, doesn’t really matter. They can all produce sharp, detailed and beautiful daguerreotypes. Modern lenses offer the advantage of having anti-reflection coatings which will reduce internal flare, and they are generally sharper from edge-to-edge, but don’t be fooled into thinking that 1850s lenses aren’t sharp, they are, and the daguerreotype process can really make them look great. The vintage lenses often suffer from internal flare which reduces the overall contrast of the image, but it can often work to a daguerreotypist’s advantage in controlling scene contrast.

Vintage lenses are NOT better at focusing the light (UV or the visible spectrum) than modern lenses. It is modern lenses that focus the three primary colors closer together (closer to the actual film plane) and have fewer lens aberrations that end up being visible in the final image. Ideally, you want the visible spectrum to focus at the same plane as any UV light that might also add to your daguerreotype’s exposure.

Another consideration is, that if you are going to make daguerreian portraits, many modern lenses are just too sharp and contrasty to produce the pleasing skin tones that vintage 1850s lenses did. I am currently using three different soft focus filters (at the same time) on a modern lens, in order to soften the light enough that flesh tones look pleasing to the eye. All the fine detail is still visible, but not so sharp that it looks harsh and unflattering.

You must also match the contrast of your lens, with the contrast of your subject/scene, with the appropriate sensitization times and development, in order to achieve the best results.

Large format process-lenses make excellent daguerreian lenses for non-portrait subjects (they’re not very fast though) because they focus all three colors precisely at the film plane. They are designed to be used at close-focusing distances of 6-10 feet from the camera, but work superbly well at infinity too. They usually have the word “Apo” in their designation indicating apochromatic correction (all three primary colors are corrected-for in the lens design, not just two), and they’re usually quite reasonably priced these days. The whole-plate daguerreotype I made of the White House in my gallery page here, was made with a 610mm Apo-Nikkor process lens, which was designed for use on a copy camera.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Corey,

The information you were given from your plater gives me reason to doubt his expertise. I would be very careful about using a plater who has difficulty plating a half mil of silver and tries to talk you into a thinner coating. An experienced plater that knows what they’re doing can put on almost any thickness of silver. It all comes down to experience, and knowing the correct current level and plating time for his particular set-up.

Electroplating is an art unto itself and is as challenging as making a technically perfect daguerreotype. The formulas used to mix the chemicals in the electroplating bath are different from plater to plater, as are the results.

The second reason for being skeptical of this plater is his suggestion that you put on a coating of nickel before the silver. If you are supplying him with polished copper, there is no need for a coating of nickel first. Nickel is needed if you are going to electroplate silver on substrates other than copper so that the silver will adhere properly, but I have never heard of it being needed for plating silver on copper.

I would suggest you contact Thad Thompson at Zapffe Silversmiths in Seattle , Washington (206-364-1919 or toll free at 866-495-2505). I have been very happy with the quality of their work, and silver plating is their specialty. They pay great attention to detail, their turn-around-time was extraordinarily fast when they knew I was on a tight deadline, and most important of all, you can talk to the guy who actually does the plating, Thad Thompson, who’s one of the owners and has countless years of experience, along with being a genuinely nice guy who will answer any questions you have. They have a website at http://www.silvergiftstore.com.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Andy,

Heed John’s advice above and always be conscious of the humidity and temperature. The slightest amount of condensation (droplets so small you can’t see them) will destroy all or part of the image, resulting in all kinds of image degrading effects. The same thing will happen if you breathe warm air on a plate after exposure. Always try NOT to bring a plate from a cool environment into a warm environment where the potential for condensation can occur.

In the ideal daguerreotype processing environment, the temperature does not vary (other than slowly cooling) from sensitization to exposure to development, eliminating any potential condensation problems. But, conditions are often far from ideal. Outdoor daguerreotypes during the winter can be a challenge even with low humidity because of the risk of condensation when you bring the plate from the cold camera into the warm processing environment.

Don’t shy away from making images during humid weather though, as sometimes you can still make great images. Your success-percentage will just be lower because of the potential for unforeseen condensation conditions. I made a 17-minute exposure on a whole-plate during a light rain a few years ago that turned out to be one of my more fascinating daguerreotypes. So, yes, you can make daguerreotypes in the rain.

Practice, practice, practice is the only way to achieve perfection. No matter how much you understand the process from books, everything that can go wrong, WILL go wrong, so you must continually experiment with your own equipment and techniques. What works for me, might not work for you.

Of all the daguerreotypists practicing today, none of us do everything the same. In fact we do very little the same as one another. We all have different equipment, techniques, sensitizing and processing times, development temperatures, and gilding methods. Even the silver surface itself is different (and reacts differently), depending on the chemicals and techniques used by the electroplater. And then there are the daguerreotypists who use clad plates, and some of them electroplate (galvanize) a thin layer of silver on top of the clad silver.

All of these factors (and many more) contribute to the unpredictability of the process, thus demanding the need to establish your own working methods with the plates, sensitizing boxes, mercury chamber, camera, and polishing method that works for you.

Regards,

Rob McElroy

Buffalo, NY

[dagist]

Andy,

There are no “tricks” for exposure compensation as it relates to plate preparation that I have ever used, or needed to use. I have never made any compensations despite the many techniques and methods I have used to polish my plates over the years. My “Ten stops over Kodachrome 25” rule has been the same for the past ten years.

Plate preparation is “the key” to achieving a full range of tones on a daguerreotype plate. Poor plate preparation can inhibit a plate’s ability to attract mercury during development which can result in the plate’s inability to reproduce the tone that was exposed on it by the lens. The effect is, that you end up with the brightest white highlight becoming “grayed” because the mercury was prevented from fully filling in all the minute spaces (highlights are actually overlapping layers of mercury, not just a single layer).

This essentially lowers the contrast of the plate and makes it “seem” like it’s less sensitive, because the resulting image doesn’t seem bright enough. The solution is often to give the plate more exposure in order to make it “brighter,” when in fact it just needs a better polish that won’t inhibit the mercury attraction in the highlights. By increasing the exposure to make it “brighter” you then raise all of the mid-tones and end up with a plate that has a lot of middle grays and light grays, which often still has no real highlight because of the ineffective plate preparation. It does seem to look better with the lighter grays, thus leading one to believe it was underexposed initially, when all it needed was a better polish.

If you look at all the daguerreotypes on this site you will see that almost no two daguerreotypists have the same range of tones from black to white on their plates, yet most of them still look pleasing to the eye. That is because of the daguerreotype’s amazing ability to reproduce a very long tonal scale. Which parts of the tonal scale we choose to expose our plate in, is up to us. And that is where the concept of correct exposure can sometimes be misleading.

I could easily expose three plates at one, two, and four minutes each, and individually each plate may look pleasing/acceptable to the eye; a testament to the daguerreotype’s uncanny ability to look great with a broad range of exposure options.

I don’t know if I answered your question or not, but always remember the daguerreian mantra which is, “Everything affects everything.” Iodine, bromine and mercury times, as well as mercury temperature, are also vital components to understanding the correct exposure for a particular scene or subject.

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

If you live in an area with an average amount of UV in the atmosphere (nothing extreme that would necessitate compensations), here’s an easy method for accurately determining the proper exposure for a daguerreotype plate. My method gives you the starting point for an average-contrast scene that is being exposed onto a plate that has been properly sensitized to record a full range of tones for an average scene, similar to the way our eyes see. Certain colors will of course not reproduce the way our eyes see them (reds, oranges and yellows) but your overall exposure will be very close every time, giving you more consistent predictable results.

You can use any modern exposure meter (no need for any UV filtering). I take mostly incident light readings, but you can certainly use reflected readings also, as long as your meter is seeing a representative sample of the lights and darks the camera is seeing.

Set your meter’s ASA/ISO on 25, select the aperture that you plan on shooting at, and take your reading. Whatever the resultant time is, add 10 f/stops. It’s very easy to simply double the time – 10 times. If your meter tells you 1/4 second at your given aperture, then just count up 10 stops from there: 1/2 second, 1 second, 2, 4, 8, 16, 32, 1 minute, 2 minutes, and finally 4 minutes. Four minutes will be the correct exposure time.

The four minute exposure will be your starting point, from which any modifications can then be made depending on your specific circumstances.

Here’s a convenient time saving tip if you’re metering in bright sun. Get a second incident dome for your exposure meter (the Minolta meters have removable domes) and fill it with a cotton ball held in place with circular pieces of typing paper. Just the right amount of cotton and paper will reduce the amount of light reaching the sensor by exactly 10 f/stops, thus allowing you take readings without doing any conversions. Whatever the meter says, will be the correct exposure for your daguerreotype. Multiple sheets of typing paper make fine tuning the process to exactly 10 stops pretty easy. I call it my “Dag Dome.”

Cheers,

Rob McElroy

Buffalo, NY

[dagist]

Jon,

In answer to your initial question, there’s no need to keep the plate close to the iodine crystals in your sensitizing box; 3.5" is an excellent distance. It will not "take forever to sensitize" (30-40 seconds will probably be average) and the increased volume of iodine-rich atmosphere in the box, should allow for less variation in time when sensitizing several plates over a short period of time. My boxes are even deeper and accommodate plates from 2.5" x 2.5" to 8" x 10".

Also, you should consider designing your box with a sliding-insert design (Mike Robinson’s is quite elegant and efficient) so that no fumes escape when you slide your plate over the crystals. This will allow for consistency in sensitization, otherwise, as soon as you lift off the top of a box that doesn’t have a sliding insert, most of the concentrated iodine fumes will escape into the atmosphere of your room.

Good Luck,
Rob McElroy
Contemporary daguerreotypist
Buffalo, NY

[Author]

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