Scent over time

January 04, 2009 at 12:00 PM in: smell, time, music, perfume

One of the more intriguing aspects of perfumery is the evolution of scent over time. The more volatile components of a mixture ("top notes") predominate at first, and as they evaporate off they give way to the slower and heavier components of the scent ("base notes").

I'm very new to perfumes, but so far I am finding myself fascinated by the complexity of the initial scents and bored by the long and relatively simple finishes. For example, Christopher Brosius describes his Violet Empire: "the violet scent perpetually peeps out from behind a shining green veil." Indeed, out of the bottle it smells fantastic. On skin, the shining green veil soon dissipates and what remains seems floral and cloying, though a better nose than mine describes the finish as "deep woods and a mild trail of leather".

Contrast this with the development of a piece of music - many pieces start with a simple exposition of a theme, slowly building in complexity as the vocabulary gets established. This is most obvious in a Hindustani classical performance, which begins by slowly exploring the intervals of a raga within a single octave, juxtaposing only a few notes at a time and letting them fade before sounding new ones. Gradually the surrounding octaves are added to the mixture, and the soloist accelerates until many tones are ringing at once. It might take ten minutes before any rhythm is introduced, and another twenty before the fireworks really get going.

A perfume seems more like a single stroke of a gong - rich and complex when first struck, but settling down to a persistent hum. But while a gong lasts a few minutes at most, the base notes of a perfume persist for hours.

Wine tasting allows another approach - you get to take that journey from start to finish on each sip, as well as noticing the slower changes over the course of several glasses. However, wines have a much more constrained palette than what the perfumers work with.

The slowest change in scent I've ever observed took years, and was probably a chemical change rather than the gradual evaporation of volatiles. I picked a flower in Marin county - something like Artemisia Californica, but with perfect small silver-gold everlasting flowers. The sage smell lasted for months, fading to a distinct smell of maple syrup. After two years the maple scent was replaced by an increasingly powerful whiff of dried urine. It took a while to figure out where the odor was coming from, but I regretfully got rid of the flower.

Rotating Time into Space

January 04, 2009 at 12:00 PM in: dance, time

Sometimes people refer to time as a "fourth dimension", which is true in some sense but also misleading since time is qualitatively different from the three spatial dimensions. You can rotate an object so its height becomes its length or width, but in the real world you can't rotate duration into depth.

MoFrames is a collection of images that do just that. The image on the right was constructed from a video of two swing dancers, with the background removed and each video frame shifted slightly forward and overlaid using a piece of software called Recreating Movement. The MoFrames site contains more examples including a page of videos that play with time, space, and motion in unusual ways.

(via kottke)

See also Golan Levin's list of slit-scan video art and research.

A Year-long Timelapse

January 02, 2009 at 12:00 PM in: time

Here's a nice year-longtimelapse for the new year. You may prefer to watch it in high-def.

One technique I haven't seen before is the use of tone mapping to prepare each frame. Tone mapping is usually used to compress high dynamic range images so that they can be displayed on a standard computer monitor. You can't show the the absolute brightnesses in an HDR image, but through tone mapping you can preserve the relative brightnesses.

For timelapse purposes, what tone mapping does is hide some of the variation in lighting conditions between frames. This means that you don't get unpleasant flickering in the video when a dim, cloudy day is followed by a bright sunny day. Shadows still appear and disappear across frames, but this is a clever way to preserve the same overall brightness.