This is just something that happened to occur to me this morning, while brewing a pot of tea, of all things.
Ferric oxalate (Fe2(C2O4)3), familiar to those who have dabbled in platinum/palladium printing, is a photo-sensitive chemical that reduces to ferrous oxalate (FeC2O4) upon exposure to ultraviolet light. If ferrous oxalate were “developed” with gallic acid or a suitable, soluble gallate salt, then the ferrous gallate (which is the key component of iron-gall ink) formed could create a dark, contrasty image.
I should point out that all this is conjecture, and practical experimentation would be needed to prove the theory.
In doing some further research regarding photographic technologies (more on that to come), I noticed a resurgent trend in online articles related to older, so-called “alternative” photographic processes.
Mike Ware is a rather retro-focussed photographer (in both subject and processes) who has published significantly on the topic of what were once mainstream, archival photographic processes, which are now almost treated as novelties. In addition to his books and essays, his website also includes a kind of archive of historic processes, including detailed instructions, hints, and an awful lot of background, on a range of rediscovered photo-alchemy. It would be a great starting point for those who are curious about progressing beyond silver-gelatin.
Of course, no post on alternative photography could be complete without a mentioning the abundant resources at Alternative Photography. Here, you’ll also find in-depth information and advice, and keen enthusiasm.
From Jake von Slatt, a modder with a penchant for Steampunk, comes this walk-through on an electrolytic etching process that can be made from a black-and-white digital image. Electroetching (aka Galvanic etching) involves no corrosive etchant, and works like the electroplating process in reverse. The process described utilises xerographic toner (carbon) from a laser-printed negative as the resist.
Note: As well as brass, this process could be used with copper plates, or most other copper alloys.
Ralph Lambrecht, co-author of the wonderful Way Beyond Monochrome and of DarkroomMagic.com, has published a description of a digital-to-analogue process involving a full-size, inkjet-printed “digital negative”. The key strength of this process is that it allows the production of archival contact prints from digital images at home. The key weakness is that the quality is still limited by the printer that you use.
A wee while ago (it must be about two years, now), I became interested in diffraction optics, particularly zone plates (aka: Fresnel plates, after Augustin-Jean Fresnel). After pursuing the technology and its properties for awhile, I filed my notes it away in my “curious_projects.txt” file, in order to concentrate on Serious Business.
Zone plates utilize the optical properties of diffraction and interference to converge (focus) incident light, and can be used to create photographic images. They consist of concentric, alternating opaque and transparent rings (“Fresnel zones”) of equal area. The more rings, the sharper and brighter the image. “Binary” zone plates have an interesting property, in that they create images with soft focus and interesting, luminescent halos (reminiscent the halation of old, thick, glass plates examples). Introducing a smooth, sinusoidal transition from transparent to opaque zones (as opposed to a hard edge) eliminates soft focus, creating a sharper image. A zone-plate objective for your SLR can be as easy to make as a good, sharp pinhole (instructions), if you can acquire a spare body cap and some contrasty film with a nice, clear base.
It occurred to me at the time that one of the big drawbacks of zone plate optics was that chromatic aberration could be pronounced and impossible to correct. I suspected that the solution could lie with multiple, RGB-filtered zone plates focussing different wavelengths. Now coming back to the problem (I have plenty of spare time, just now), it occurs to me that coaxial C-M-Y zone plates could present a more elegant solution. The question now is how to prototype a sandwich of coloured zone plates, precisely focussed for three primary wavelengths. I’m not sure I can even get good slide film, these days.
The following is essentially a list of lists. Specifically, lists of developer formulations for film.
To date, the film developer with which I’ve had the most experience is Ilford’s ID-11, or the very similar Kodak D-76: “standard issue” for a student of photography, at a time when the available range of analogue photography products is rapidly thinning. As film becomes commercially unsustainable, photographers in that medium may need to take control, and hack their own chemistry.
Further to my earlier post on coffee-based film development, Caffeine-Ascorbate Developers are a class of developers that you can literally make in your kitchen.
Additional linkage: Developer recipes; Development times; Discussion & examples