Thursday, January 7, 2021

Ruminations on Eating Photons


Plants see photons.

People see photons.

Plants eat photons.

Do people eat photons? I suspect not. It would be too light a diet. 

The above was my first reaction to Carl Jennings’s latest column, “Eating Color: Color Perception in Plants” [ISCC News # 492 (2020), pp. 5-8]. Carl wrote from the viewpoint of an artist who embodied the title metaphor in his works. I, of course, tend to pursue more technical implications—starting with a joke. And, unlike all the trite photon jokes I had seen on the Internet, this one seemed to have a serious teaching point.

Let’s start with the seeing of photons. The chemistry of vision involves amplifying a rather weak photon signal (weak because it must be divided up in space, time, and spectrum), and the agent of the amplification is the discharge of a battery. When the battery is discharged, it must be recharged (using a lot of metabolic energy) before it can be used again. (Sometimes, as with retinal rods, the battery gets discarded and replaced, not recharged.) Seeing, either by plants or by animals, involves treating the photon as a signal and amplifying that signal chemically. Any vision system, plant or animal, uses energy by combining oxygen with other elements; hence respiration is a prerequisite for seeing.

Now let’s proceed to the eating of photons. Photosynthesis also has a battery that is similar to vision’s battery, but the energy goes the other way. Not only the photo-active material, but the whole organism increases in mass and energy as a result of the incident photon energy. Carbon adds to the mass of the organism and oxygen is released. 

I’ve just described the eating of photons by plants. Do animals eat photons in the same way? No, and I think the reason is that animals are not able to use the photons as a direct energy source. They have to eat in other ways, which are familiar to us. Photons are too light a diet to sustain animals directly. [One must note a small exception of this rule, the creation of Vitamin D via the Sun’s UV radiation on skin.]

I published a little about this subject in ISCC News # 427 (2007), p.7: “Power to the Pupil” (not a Hue Angles column). There my main focus was the creation of batteries using rather large amounts of visual pigment from animals, and also the design of solar cells using principles very similar to those used in certain cameras.

Some of you might complain at this point about my colloquialism of “seeing photons” in place of “information-processing an electromagnetic signal” and “eating photons” instead of “transmuting electromagnetic power into stored energy.” In anticipation of such a complaint, I can only say that less colloquial language might deny me immortality in the immense archives of photon jokes that persist ready for simple Internet search. Enjoy. 

Michael H. Brill

Monday, October 26, 2020

The Revolving Door between Color Science and the English Department

Past Hue Angles columns have featured examples of career changes from color science to other areas. (See Issue #250 [2011] on Terry Benzschawel’s transition to Wall Street quant and Issue #475 [2016] on Mike Stokes’s transition to data privacy.) 

In this article, I describe Suguru Ishizaki’s transition from color science to an English department. Such experiences can inspire hope for successful career transitions in the field of color science even in the current job crisis.

Ishizaki’s contribution to color science is heralded by his 1994 Color Imaging Conference paper [1], also extended in a successive paper [2]. He undertook the prodigious task of coloring sub-areas on a color-coded map or chart so that each sub-area, subject to spatial induction from its neighbors, would match an intended color in the key to the chart. The task is hard because every time you change a sub-area color, you must also change the neighboring areas to preserve all the color matches with the key. The process is iterative and multi-dimensional. To my knowledge, Ishizaki’s is the first and only attempt to capture and control such complicated and inter-dependent conditions for asymmetric matches. (Usually investigators look at only a center field as influenced by a single surround, and do not ask the matching question.)

Starting with this work (which led to his Ph.D. at the MIT Media Lab), Ishizaki built a career, alternately in academia and industry, based on a broader over-arching theme of human communication through design. He started at the Design School at Carnegie Mellon University (CMU), then worked at Qualcomm on early mobile applications, and ended up at CMU’s English Department, where he is now an Associate Professor. Dr. Ishizaki’s current research area is Technology-Enhanced Learning for writing and Computer-Assisted Rhetorical Analysis [3].

Several people I know started as English majors and ended up in color science. Bob Karpowicz, who became a product manager at Datacolor, had an undergraduate English major. Mike Tinker (who became an expert in color digital cinema at Sarnoff) started from a B.A. in English literature; then, as a graduate student in English, he wrote a computer program that recognized writers by their word patterns. That wasn’t accepted as a thesis topic, so Tinker pursued another topic to a Ph.D. in English with a minor in computer science. 

And I myself was an undergraduate English major, though this is unacknowledged on my diploma due to a binary choice being given to me on graduation day. (How English departments have changed since then!)

But whereas in all these cases the door of the English department was marked “Exit,” Dr. Ishizaki found a door marked “Enter.” I hope someday that he returns to color science to continue the career he started and that nobody else can match. Or perhaps someone else will continue his pivotal work.

[1] Ishizaki, S. Adjusting simultaneous contrast for dynamic information display. Proceedings of IS&T and SID's Color Imaging Conference, Scottsdale, 1994: pp 137- 140. 

[2] Ishizaki, S. Color adaptive graphics: what you see in your color palette isn’t what you get! CHI ’95: Conference Companion on Human Factors in Computing Systems. May 1995, pp. 300-301.


Michael H. Brill