Becquerel Development Wavelength

[Jon Lewis]

Does anyone know the pertinent wavelengths for Becquerel development? I looked around and found that amberlith passes about 580nm and above and rubylith passes than about 625nm and above. Since IR starts around 750nm I’m guessing the active wavelengths are somewhere between 625nm and 750nm.

I suppose my question really is: if I were to use a light with a narrow pass of say 725nm or 730nm (like an LED), would it work to develop the dag?

I can always find out by experimentation but I just wanted to see if anyone has had some experience in this area… ” title=”Very Happy” />

[jdanforth]

Well SHIT, you learn something new everyday! After I wrote that post I kept mulling over the issue in my head. I hadn’t really thought about it thoroughly before but it makes sense to me that UV would fog the image. I don’t know why IR or visible red works but you’re certainly right about the UV thing. I’m such a putz.

[jdanforth]

I have spoken with a handful of photography students that are experimenting with daguerreotypes. Many of them use UV development boxes like these: http://www.photoformulary.com

[Jon Lewis]

I’ve used those for cyanotypes and platinums and I’d expect they’d work well for contact printing dags but I was wondering more about becquerel development. Since you need a red light, is there a magic wavelength that’s needed or will anything on the red end work?

[botticelli1972]

Early on I purchased a large roll of amberlith and have found it works very well and predicable. It is a standard that has been used for years. I have also tried deep yellow, orange and red gels sourced from art supply stores. The yellow worked but the image looked weak, the orange was decent (it was close in color to the amberlith)and the red developed way to fast and I actually watched the image appear and then the whole plate eventually go dark in just a few minutes. I have the amberlith taped to a piece of UV blocking plexi and use binder clips to attach it to the film holder and then pull the dark slide. I have used the same piece for five years.-Larry

[drdag]

I did not realise that there would be so much variation, I use rubylith and if the sun isn’t shining then I use a 150 watt halogen light, it does develop quite quickly

[Jon Lewis]

What I was thinking about doing was creating an array of red LEDs to develop dags. In theory it would create a small, self-contained dag developing unit that would give consistent results day or night with less heat problems than solar or high output lights. My concern was that red LEDs only emit at 625nm or 730nm and I wasn’t sure if such a narrow frequency could be used. Since rubylith starts passing light at 625nm I’m starting to think it’ll work. I guess I’ll just have to give it a try!

[jdanforth]

I think that you’re looking at the wrong end of the spectrum. I had thought that Becquerel dags are developed not by the infrared but rather by the UV that the red film allows through. The reason why red film works is that the dags are orthochromatic so the red light doesn’t affect the image.

Red LEDs, unless they happen to output some UV by accident (and they won’t), won’t do anything for you except eventually make your plate black.

UV LEDs on the other hand…

If I’m incorrect, please correct me!

[botticelli1972]

I believe that you are incorrect, as I have always included a UV blocker with my amberlith to prevent accidental fogging of the image, thus it is indeed the red end of the spectrum that does the development and I would imaging that red LED’s would work and might be a nice way to accurately control times. I use the old fashioned sun technique which as we all know is unpredictable. I have heard of some people using the dark IR filters to develop becquerel dags with success but I have not tried it myself.-Larry

[Jon Lewis]

Once you’ve learned everything it’s no fun any more ” title=”Wink” />

Since dags are sensitive to blues and UV and are developed with reds and IR it would seem possible to create a box with an interwoven matrix of UV and IR LEDs that would allow contact printing and development of dags without the need to move the plate. Now I just need a way of polishing, fixing, and gilding in the same box and I’d have an automatic daguerreotype machine! Not sure how useful such a device would be but it’s fun to think about ” title=”Smile” />

[Author]

Posts