Preface
I really like instruments. Instruments in a broader sense as the tools and methods, which enable creative or technical endeavors, but also specifically machines - devices tasked with a certain purpose of processing information, energy, and matter, transforming them into more useful or suitable forms. These could be optical, electrical, mechanical, acoustic equipment in any engineering or artistic environment. If there is an instrument, I’ll probably be excited about it. This excitement goes way back, and I still keep around childhood drawings of my “inventions” :
Ever since, I’ve greatly enjoyed creating instruments - often gratuitously (because Schlieren photography, high voltages, x-rays, lasers, and spectroscopy are fun), sometimes for educational demonstrations, and sometimes because I had a certain application that required them. A majority of the latter were photographic in nature - many pinhole and primitive cameras, a large format monorail, printing frames, water baths - and wherein all of this becomes relevant to the title of this text.
In the summer of 2014, between high school and college, I became interested in photographic chemistry research and sensitometry. So, I constructed some basic instruments to make experiments more rigorous. Among them was this:
Hacked with available flotsam and plenty of wishful thinking, it was a somewhat functional densitometer, meant to measure the optical density of 35mm test strips. As soon as I built it, I knew there was much, much room for improvement. I spent a good two weeks researching densitometers, sensitometry, optio-electrical systems, and went as far as ordering some components from Germany. Then, college happened, and the project spent 4 years dismantled, gathering dust in my darkroom.
Yet, even as I dived into college life, once in a while, I’d be haunted by the ghost of my unfinished instrument, and I’d daydream about amplifier circuits, optics, analog computers. And I knew that one day, I’d build the instrument proper, and the day came this fall, when I rediscovered the parts I had ordered.
Why?
If all this sounds odd, I agree. I don’t understand why, of all my projects, the densitometer has pursued me. I have no real motivation. As soon as I complete the instrument, I will likely leave it to gather dust again (as a “proper” density meter), as I’m no longer doing photographic research. Furthermore, there are plenty other interesting ideas I’ve had during this time, but none have prompted me to in-depth consideration and active work.
My initial response was being stifled at how my thoughts kept drifting in that direction. Then, I actively opposed starting to work on the device, dismissing the idea as pointless. Yet now, I have made significant progress in completing the instrument.
Why?
I genuinely don’t know. A somewhat common theme in my postgraduate life. Matter of principle, I guess.
Philosophy (because tangents)
My degree is in the natural sciences and (somewhat) the visual arts. However, I almost feel an engineer at heart. I am fascinated with instrumentation and industrial design. I like processes as much as their results, the entirety of a system and its principles. This has caused me much trouble choosing an education and career path - my core interests are applicable to a broad scope of professions. To add an extra bit of confusion, I’ve had a consistent desire to teach, share knowledge, and stimulate creativity. I have been told that the above are not mutually exclusive, but finding the balance and acting on it at this particular juncture has been tricky.
As I worked on the densitometer project, partly in spite of myself and partly to get it out of my mind, I decided to document my progress as a series of articles/posts. I remembered being active on forums, such as APUG, now Photrio, as well as sharing images and information on a Wordpress blog, and the degree of satisfaction they brought me. This is the natural continuation.
The course of researching, designing, and prototyping the instrument has been an interdisciplinary exercise in electronics, optics, reverse engineering, hacking, and I somehow managed to squeeze some actual chemistry in, as well. I had to to obtain new skills and contemplate design principles. As a result, this project has been among my most difficult and most (maybe?) methodically thought-out. I’m not sure what the final result will be. It is probably not an elegant solution, in every sense of the expression. I have almost certainly overthought aspects of it, sometimes justifiably, sometimes purely as overkill.
The title is an homage to the great Bob Pease, analog design expert and technical writer. His column “What’s all this analog stuff, anyhow?" in Electronic Design Magazine has been the source of much edification and inspiration. I hope to write this series in a similar tone and style, with the insignificant difference between the authors of (at least)a BSEE degree from MIT and half-a-century of experience. My qualification is … “jack of all trades, master of none.”
The aim of the articles is partly documentary, partly didactic. I would like to describe my design decisions and what dictated them, while simultaneously providing some background theory and the practical challenges and pitfalls that I encountered or considered. I will attempt to be as thorough as my current knowledge and experience allow. Hopefully, the result will contain useful information and solutions.
Let’s see…
P.S. I look forward to feedback and comments!