This image, which is 20" by 30" print on photopaper, is a so-called "spectrogram" of a short musical segment. This image is taken from a video I also created, which I generated using a spectrograph software app from a musical recording of an improvisation I performed on a vintage Minimoog Model D synthesizer. This recording was made at EMEAPP, the (amazing!) Electronic Music And Education Program, a nonprofit organization dedicated to the preservation of, research, and education about vintage electronic musical instruments. One can find technical papers on the sound circuitry of the Minimoog that I co-wrote with others on their site as well (which access requires a free membership signup).
For those interested in the technical details of this image: The bands of light in the left half of the image display the amplitude of the harmonics of some low notes as functions of time (with time advancing vertically from the past (the bottom edge) to the the present moment across the middle). That is, the image displays "spectrum" of these notes over a short period of time. The brighter lines to the right half display the harmonic content of the Minimoog's filter in "self-oscillation," and varies wildly because I was manually manipulating the "Cutoff Frequency" of the Minimoog's "Voltage Controlled Filter" with my left hand to obtain a wild whistling-like effect on top of the low notes that I was simultaneously playing with my right hand. A classic Moog synthesizer playing technique!
The recording can be listened to or obtained on my Bandcamp site here: