A Becquerel Daguerreotype in a lunchtime?
Can I make a Becquerel Daguerreotype in a lunchtime?
I’ve wanted to make a Daguerreotype for a long time, the problem is you need mercury to develop the photograph, you need silverplate to capture the image on, a plate camera, iodine, thiosulphate and various other materials. My concern for a long time has been getting silverplate to actually create the daguerreotype on, it used to be readily available but I’ve not been successful in acquiring any recently despite looking in many secondhand and house clearance shops. One thing I do have lots of is copper clad PCB material, this has anywhere from fifty to a few hundred microns of copper stuck to either fibreglass or resin bonded paper substrate. PCB material is easily cut and handled, so if I can just find a way to silverplate this then I’ll have a ready stock of material I can make daguerreotypes on.
Let’s plate some copper.
I had some offcuts of PCB in the lab, they were the fibreglass type and I did wonder if any texture would show through the copper. A quick spin on the polisher grinder with very fine paper (2000 grit) and I was able to get a copper surface that showed a small amount of texture but was just a mass of scratches - some of these were almost certainly existing before my attempt to polish the copper. I gave the copper surface a buff and final polish with some random metal polish I had laying around.
Once polished there was an almost mirror like surface, but still quite a few scratches and some texture from the fibreglass. I cleaned the board with running water followed by a rinse with ethanol and a final rinse with acetone, the board was propped up on a corner to dry.
For a plating solution I made up a 50ml of 1g/L Silver nitrate solution. I chose a fairly dilute solution because I didn’t want to plate the copper too quickly, I thought I’d get a more uniform and flatter layer if the silver plated down more slowly. It was a nice idea, but almost immediately I got a very patchy plating, it seemed better towards the middle of the plate and almost nothing seemed to happen at the corners (they were probably not very clean after all).
Wiping the plated surface with clean cotton wool removed quite a lot of loosely attached silver, darkening the cotton. The surface was quite easily polished with just the cotton wool - but it was obvious the layer of silver wasn’t very thick at all.
Sensitising the plate
With the light off, I put a few grains of iodine in a petri dish with the plated side of the board upwards. The dish was covered and left to stand for 10 minutes. When I came back to check it there were traces of iodine on the top lid of the dish and the smell of iodine when the lid was removed. Using a red LED torch I checked the plated surface and could see no crystals of iodine on it. I transferred the plate to an opaque envelope and took it to the camera.
The Camera & Exposure
There was no camera. I hadn’t planned that far ahead. What there was was a lens from an old slide projector, a room I could make dark and a well let scene beyond the darkened room - in effect I could make a camera obscurer. So I did. The lens was held on the window with some blue-tack, the rest of the window covered with a black plastic bag, and the light through the lens projected onto some paper so I could check the focal distance. I held the plate at the focal distance until I figured that all the involuntary movements I was making would certainly not make for a clear image. I estimate the total exposure time was about two minutes give or take.
The standard Daguerreotype development requires the use of mercury, the Becquerel type uses red light in a little understood process, that somehow affects the sliver in the exposed regions and not in the unexposed regions. Not having a rubylith lightbox, I used the next best thing (the only thing I had) a 10mW HeNe laser and a diffuser. I diffused the HeNe light to just cover the board and left it to “develop” for 20 minutes.
After a cup of Tea (~20 minutes), I shut off the laser and dumped the board into a solution of thiosulphate (24g pentahydrate in 100ml water). Almost immediately a circle showed up on the board and the silver outside the circle was removed. I used the red LED torch to watch this. After about 15 seconds in the liquid I pulled the board out, rinsed it under the tap and snapped a photograph of it.
The circle is as best I can work out, the image circle of the lens I used. I believe the rings to be a combination of movement when I was holding / positioning the plate and chemical effects on the copper / silver.
So, can you make a Becquerel Daguerreotype in a lunchtime? I’m not convinced the answer is 100% No, but it’s also not 100% Yes. I think I captured some light on to a light sensitive layer of silver, and fixed it enough that it didn’t immediately wash away or fade to nothing. There’s no evidence of the scene I was trying to capture, but there is the image circle of the lens. I think the only way is up from here. Time to get some professional silver plating done.