I am a lifetime enthusiast photographer, but my career has been in Optoelectronics and Engineering, designing and building the devices that power today’s optical transmission for the Internet. When the pandemic hit, members of our local camera club were looking for activities to try, share and learn from, but at a distance. I chose to build a Harmonograph, which I thought would enable a good variety of images to be produced. I have really surprised and delighted myself! I am discovering new options and patterns almost daily; it is enabling me to explore a range of photographic images which I think are unique and unbounded!
A harmonograph is built around pendula. Victorians were amazed and enthralled by the pendulum. They were used to prove the rotation of the Earth (Foucault) and to measure the differences in the force of gravity at sea level and the tops of mountains. The Harmonograph (there is plenty of material on the web) became a ‘gentleman’s toy’ and could produce quite intricate and beautiful patterns, almost by magic. A traditional harmonogram is the record of motion of two or three pendula, using either a pen and paper or a needle and smoked glass. There are plenty of programmes and apps available today that simulate harmonographs. They produce complex and interesting patterns but seem to me a bit synthetic and flat. I wanted to try and make a harmonograph that recorded the image photographically, so that the velocity of the light source would be correctly rendered through intensity in the image, giving a 3D feel that is absent from these computer generated harmonograms (and from pen/ink renderings)
My prototype was built with a stepladder, wood and string. This produced interesting results, but was very limited in its settings, and the pendula decayed rapidly, reducing the 3D ‘feel’ of the images. I had no option but to improve my engineering!
My machine now is well over 2 metres tall, and precision made out of oak, with hardpoint bearing screws and comprehensive adjustability. It is a ‘platform’ I can use to adapt and change and try new things. It is also quite mesmerising to watch!
The machine has two platforms, the top one with the camera and the lower one with the LED light source. Both are suspended on gimbal frames, so they can swing in two dimensions. The period of each can be adjusted by moving the camera or LED platform up and down, with swing periods from over a second down to about half a second. The gimbals can be fine tuned to add or remove ‘precession’ where the platform tends to swing from a circular to a linear motion and back. It is like the multiple strings for each piano note; they are not all exactly the same frequency, giving the tone depth and colour. Too much detuning isn’t nice though, and the same is true in harmonograms!
Adjusting the light level, ISO and exposure takes time and experimentation. I find that it is best with a stack of ND filters on the camera, as the LEDs are quite bright; this reduces the sensitivity to background light, as exposures can be up to ten minutes. Everything has to be set to manual, with no IS. Live view is also essential, and remote shooting is a real boon. Long exposure noise reduction also works really well, otherwise all the hot pixels show up! My camera is an EOS R, which works brilliantly in this application. Patience is needed, as the long exposure noise reduction takes as long as the exposure. Any minor jogs, door closures or earth tremors will ruin the capture, and you don’t know what you will get until it appears on the screen. Sometimes a magic moment. Most times ‘in the bin’.
The simplest and easiest patterns are produced when the periods of the two platforms are almost the same; some precession is needed to give the patterns an interesting form.
The convergence of this project with music quickly became apparent – the most coherent patterns are produced when the two platforms are tuned close to the integer ratios from music, such as a major fifth (3:2), perfect fourth (4:3), minor third (6:5). The patterns become more complex with these tunings. For instance with minor third tuning, there will be 11 peaks in the pattern and 5 for a major fifth; adding precession folds the patterns, further increasing complexity.
‘Convolution’ – tuned close to a major fifth, with a fairly high level of precession. I think this invites the viewer to unfold and explore, seeking ways through the form.
For ‘7th Starburst’ the platforms are tuned to a 15:8 ratio, corresponding to a Major 7th. The pattern repeats 23 times moving round the form, giving the starburst effect. Allowing a fairly long exposure has resulted in the complex glow from the centre of the figure. Sometimes it helps to reduce the LED current as the platforms decay, avoiding burn out.
When the two platforms are tuned an octave apart (2:1), the patterns can be surprisingly beautiful and complex. This is about the limit of tuning on my current machine. Any increase would require a large hole in the ceiling!
‘Entwined’ – near octave tuning, with quite strong precession set to give the linen fold in the tails of the form. To me this was evocative of two futuristic forms or beings, entwined together, or maybe some deep sea creature from the Abyss.
Producing patterns like this I think hastened the transition from ‘technology’ towards ‘Art’, although the borderlines still remain unclear to me. Prior to this, I wanted the patterns to be perfect, with no edge clipping or jogs, no noise and no highlight saturation. So I tried other things, including dual and multicolour captures using modified RGB LEDs and harder cropping, maybe saying something more than ‘great pattern’.
Around the time of the US election I was experimenting with red-blue switching, trying to render an entwined form, a dream of the Republicans and Democrats maybe working harmoniously together:
Once I had introduced colour (which I could readily control and adjust with a Raspberry Pi micro-computer https://projects.raspberrypi.org/en/projects/physical-computing) all sorts of other possibilities emerged…
I worked on the Rainbow motif, celebrating diversity and our star health providers throughout the Pandemic in the UK…
I think these are fine, harmonious patterns, reasonably artistic. With further work, the results could say something quite different. In the composite below I was trying to represent the year 2020, starting with a bit of a stir, and ending nearer chaos.
Adding the colours showed me I could move further down the road of abstraction, leaving ‘off’ periods in the light, separating the different colour forms…
This is recorded with near Unison tuning, so the decay is slower, resulting in the lines being so close together that the red form is almost solid, enfolding the blue form. The forms are very harmonious, but with some separation, and belong together.
Finally, taking the switching further, this triptych is entitled ‘Ribbons and Bows’ and shows the different but related forms that can be produced by fairly subtle changes to the start conditions.
‘Ribbons and Bows’
I think I have many more months of experimenting and fun to come with this set up (and derivatives). I’m thinking about attaching position sensors the platforms so I can digitise the movements, then upconvert to audible frequencies… so I can hear what a pattern sounds like!
This project has encompassed many of my passions and interests – photography, physics, engineering, optics, electronics, woodwork, art and made me think and learn more about music. It is hard to envision a project that can do more than this.
The patterns are all produced by light, recorded photographically and moulded only by the force of gravity, just like the great star fields and constellations in the night sky! I hope you have enjoyed the story.
More images from this Harmonograph ‘Harmony of Light’ project can be viewed on http://andrewcarter.smugmug.com