Color Theory - where Science/Technology and Visual Arts meet

Have you ever wonder what the world would be like if we can only see black and white, and shades of gray?  Have you ever wondered what do human’s animal friends and foes see?  Many of us played with crayons when young and learned the basics of theory of color in the introductory science class.  But if you want to tweak colors in a photo using software like Photoshop, or want to mix color paints to create a new color for desired effects, what works and what doesn’t, and why? What is color and how much do we know about color anyway?  Below is the first installment of my report from my current study of Color Theory that is a required basic course for most Fine Arts degrees.

Color begins with light; if there is no (visible) light, there will be no color perceived or to speak of.  Everyone has been awed when young by rainbows but it took quite some time before scientists figured out what is rainbow, how they are formed and why they look the way they do.  Isaac Newton, one of the greatest physicists, published his seminal work Opticks in 1704 in which he discussed, among other things, how (white) light can be split (by refraction) into color lights with a prism.  He identified the seven basic colors of light seen after splitting - Red, Orange, Yellow, Green, Blue, Indigo, and Violet, or “ROY G. BIV” as every American kid was taught in grade school.  Of course, light spectrum is continuous and there just aren’t enough names to describe them all with arbitrary granularity.   Sir Newton also showed that white light can be created with overlapping lights of colors.

We now know that technically speaking, humans can only detect different “colors” in a narrow spectrum of electromagnetic (EM) radiation between roughly 390 to 750 nanometers (nm) in wavelength, or 400 to 790 Tera Hertz in frequency (see the reference chart below for the whole range of EM radiation). Given such a wide possibility, one should not be surprised that different species of animals and insects “see” the world differently.  It turns out that many birds, bees and insects can see ultraviolet (UV) wavelength in 300-400 nm And some snakes, fishes, and mosquitoes can see infrared (IR) of wavelength in 700-3,000 nm range (where humans would need help with a night vision device to “see”).   Note that regardless of the color, there are many animals and insects that can also detect objects under much dimmer light compared to humans.  

While evolutionary biologists can tell you and I why and how such distinct visual sensory systems came about, scientists now have a pretty good idea how human vision works.  In particular, humans have a huge number of neurons (photoreceptor cells) in the retinas of our eyes that can detect and convert the light information to signals and transmit them to the brain for further processing.  There are about 120 millions of photoreceptors (called rods) for detection of light beyond some intensity and 5 millions of photoreceptors (called cones) for detecting lights of certain wavelengths (see the diagram to the right of the structure of eye).  It so happens that humans have three types of cones that are capable of detection of color Red, Green, and Blue (RGB) that determines pretty much what colors we see.   

In contrast, other species of animals and insects have distinct ability in color detection depending on how many types of cones they have and what wavelengths of light they can detect.  For example, cats and dogs have only two types of cones and can only detect Yellow and Blue colors but not the red.  Some mammals have none and are color blind. On the other hand, some birds and fish have four types of color-sensitive cone cells, giving them greater sophistication in distinguishing colors.  And bees have three types of cones like humans but they can detect shorter wavelengths and can see the ultraviolet as mentioned earlier. They use their better color vision to search for nectars and can distinguish flower colors invisible to human.  At the other end of spectrum, mantis shrimps have ten types of rods and presumably see a lot finer colorful world.  The bottom line is even when some animals, insects can detect radiation in overlapping range of the EM wave, they don’t necessarily see the same colors.  For more detailed discussions, you can read the excellent article Color in Nature by Philip Ball. 

Astute readers by now have probably noticed that when discussing how colors are detected by our visual system, there was no mentioning of the source of the light.  What Sir Newton has focused on was the white light itself as emitted from a light source and its color as seen by the eyes.  The source could be the sun, a light ball, a flash light, a TV screen or a computer monitor.  And it is an additive process, i.e., our eyes receive all the component lights of various wavelengths combined together.  For the rest and majority of the colors of objects we see, eyes receive lights coming from the reflections of the light shined on the objects.   Thus if the object absorbs all lights completely, we would see and consider it has color black.  In other words, the perceived color of the object (e.g. on a printed page) is the result of subtraction: our eyes receive original light minus whatever wavelengths and amounts of light spectrum that were absorbed by the object.   For more detailed discussions, one can start with the Wikipedia article pigment and the references therein. 

 

Artists (and other –ists) before and after Newton have been well aware of the distinctions between color of light and color of an object empirically.  However it wasn’t until 100 years later in early 1800s when the German writer/scientist/artist Johann Goethe challenged and addressed the limitation of Newton’s theory of light and laid the foundation of a practical theory that are used in our daily life now.  Color theory is in fact still an active area of research as it touches upon and calls for contributions and inventions from artists and scientists ranging from biologist to cognition psychologist to understand and make use of our visual ability fully. 

With the introduction above, we are now ready to talk about color models.  A good place to start for any theory is a good model – something that provides us the structure and means to approach and discuss an otherwise intractable and complex phenomenon like our perception (and illusion) of color.  For historical and technical reasons, there are unfortunately many different color models for different applications (while sharing some of the same vocabulary) that cause a lot of confusion for beginners.

Most of us have heard of the popular RGB color model which is based on the use and additive properties of the additive primary colors Red, Green, and Blue lights to generate a broad range of colors.  It is most often found in TV, mobile phone, and computer displays, scanners, camcorders and digital cameras.   There is also the CMYK (Cyan, Magenta, Yellow, black/Key) color model used in color printing that relies on the subtractive properties of the primary colors of Yellow, Magenta and Cyan.  Alternatively, artists typically use the RYB color model and refer them to 12 colors Color Wheel – three (Red, Yellow, and Blue) subtractive primaries along with nine secondary and tertiary colors that are placed around a circle uniformly.  The cool thing with the color wheel is that the pair of diagonally opposite colors – the so called complementary colors, when mixed, neutralizes each other and produces eventually a gray.  See the figure to the right that I did in the class using only Yellow, Blue and Red acrylic paints. 

Since both RGB and CYMK color models are device-dependent (i.e.: different devices/material necessarily detect or reproduce a given RGB value differently), there is no fixed representation of the color and they do vary from manufacturer to manufacturer and difficult to convert and match. Continuing efforts have been made to create device independent models that can describe all the colors visible to the human eye and are perceptually uniform (i.e., a change of the same amount in a color value should produce a change of about the same visual importance). Of particular interest is the most recent Color Appearance Model standard - CIECAM02, ratified by CIE (Internationale de l´Eclairage or The International Commission on Illumination, an international non-profit organization).  The model has been quantified with rigorous subjecting testing in lab and careful measurements of perceptual responses.  It is based on the widely used Munsell color system that separates color-making attributes into three independent dimensions - hue, value, and chroma.

A 3-D diagram illustrating the notion of Munsell color system is shown to the right.  Technically, Hue codes the distinctive color from red, blue, green and yellow.  Value (or lightness vs. darkness) indicates the relative brightness to the brightness of white under similar viewing conditions whereby brightness is the perceived amount of light emanating from the observed object (just think of the brightness associated with different wattage of of common household light bulbs).   Chroma is the colorfulness relative to the brightness of white under similar viewing conditions whereby colorfulness is the degree of difference between a color and gray which is neutral in color.  Note in this definition, chroma is different from saturation which is the degree of purity of a hue.  That is, chroma is the purity relative to gray and thus to other colors while it is only meaningful to talk about (relative) degree of saturation of a color by itself.  

So far we have been focusing on aspects of color theory from scientific and technological perspectives. Scientists seek to understand, explain, and to predict the phenomena.  Technologists strive for creating methods and tools that allow people to perform tasks which are otherwise difficult.  Artists on the other hand express themselves and communicate to people via their sensory system plus imagination.   Indeed, artists have been creating visual languages in color intuitively and successfully long before science was even developed.  In my next installment of color theory, I will show some illustrative examples of what one can do with colors.   Talk to you soon!

7 Billion and Going Strong

According to the United Nations, the world population reached 7 billion on Oct 31^st, 2011, the Day of Halloween Day.  And the honor of being the 7 billionth baby went to a girl who was born in the Philippines (see a news report and party photo.)  If UN’s goal was to sound the alarm (again) and draw attention to the concern about our ever increasing world population, they have got my attention.  

There have been continuing discussions by scholars, analysts, and journalists of the recurring worry – how much longer can the planet earth support its ever increasing population and how many people can planet earth sustain. It turns out these questions are very difficult to answer with certainty and the estimates vary widely with different assumptions and extrapolations.  Nevertheless, the exact numbers is not nearly as important as the methodology of the analysis and the few basics and boundary conditions.

To begin with, let us agree on why the population keeps growing and what is required to keep it at a constant level.  The answer to the question of “why” should be intuitive and non-controversial: any system would be growing if the incoming rate exceeds the outgoing rates in long enough time scale.  We experienced it frequently in our everyday life and observed when the rates are not balanced.  For example, we saw our kitchen sink backed up when the drain was clogged; we encountered long delays at bridges and tunnels during rush hours when arrival rate of traffic exceeded the rate of what these conduits can clear.  There is no difference for population: when the rate of births is higher than the rate of death, we can expect the population would grow, ignoring the time lag factor of life span for now.

How have we been doing lately regarding these rates?  The frequently used technical term is the (crude) birth rate (CBR) which is simply the number of births in a given year for every 1,000 persons in a given region.  If you go to Wikipedia and look up the List of countries by birth rate, you can find that for instance, CIA World Factbook estimated in 2009, birth rate by country/region ranged from the highest in Niger (a western Africa country) at 51.60 (per thousand) to the lowest in Japan and Hong Kong at about 7.5, while U.S.’ CBR stood at 13.82 and India was at 21.6.

To make some sense of these numbers, we need to compare them with the (crude) death rate (CDR) of these countries.  Death rate in Niger, Japan, Hong Kong, U.S. and India were estimated by the same document at 14.83, 9.54, 6.76, 8.38, and 6.23 (per 1,000 people), respectively.  In other words, there was an estimated net increase of population of 37, 0.74, and 4.4 per 1,000 people in Niger, Hong Kong and U.S. respectively and a net decrease of 2 per 1,000 people in Japan in year 2009.  Since U.S. had a population about 300 millions, it simply says there was an estimated 1.3 million net increase in population.

An alternate and intuitive way of looking at the growth rate of our population is to consider the total fertility rate, which is the average number of children born to each woman over the course of her life.  The reasoning goes like this: if the average number of female babies born per woman in her childbearing ages is exactly 1, then the population would remain a constant since that female baby would replace the mother, no more and no less.  The equivalent technical term of replacement fertility rate is thus also frequently used which is simply the average number of children, either male or female, required to replace the mother.  Once we account for the skew due to chromosome difference (there are slightly more boys than girls born due to the built-in bias in reproduction process in favor of the Y chromosome) and the infant mortality, the replacement fertility is at about 2.1 births per woman for developed countries and more than 3.0 for many developing and underdeveloped countries.  Niger’s fertility rate of 2009 was estimated to be 7.07 (according to the CIA World Fact Book). 

Some may argue that we should not worry since the world population growth rate has been declining in recent years and has reached a very modest rate of 1.1%.  Ignoring issues of huge disparities among regions and countries for the time being, should we be worried or not?  Professor Emeritus Albert Bartlett of University of Colorado at Boulder had the following to say about the reality of steady growth and how most of us ignore it:  "The greatest shortcoming of the human race is our inability to understand the exponential function."  He was referring to our failure in recognizing how explosive it really is of anything that grows at a constant rate.  Watch the lucid lecture he gave below, entitled Arithmetic, Population, and Energy.   It should convince you with just the first 10 minutes of the videos that steady growth is scary unless it happens to be your investment and bank accounts.

Now we can return to our original questions of how much longer can the planet earth support its ever increasing population and how many people can planet earth sustain.  We are going to focus on the 2^nd part of the question since we already have the ideas of the growth rate.  If we have an estimate of how many people the planet earth can sustain, we can easily estimate how long it would take for the population to grow and hit that level with the given population increase rate and various assumption like what Professor Albert Bartlett has demonstrated.

The big picture looks as follows.  We can all agree that the minimum and most basic resources for our survival are obviously food and fresh water (assuming air is not an issue).   It has been estimated that planet earth has over 300 million cubic miles of water but only 3% of it is fresh water.  Further, two third of the fresh water is in frozen form such as ice cap and glaciers which is necessary to keep the earth cool and sea level in check.  In all, we have about 3 million cubic miles of (mostly renewable) fresh water and only 0.3% (or almost 10,000 cubic miles) of it is on the surface (in lakes, rivers, snows, etc).  The rest are underground and not necessarily accessible. 

You may or may not know what we drink directly is just a tiny fraction of our total fresh water consumption.  The dominant consumption of freshwater is actually for food production – 70% of the fresh water consumption is for agriculture.  With today’s efficiency, we need for example, 3,000 gallons or over 11 metric tons (11,000 Kilograms or 24,000 pounds) of fresh water to grow one bushel (about 25 kg or 56 pounds) of corns.  We need about 900 metric tons of water to grow one metric ton of wheat.  And it takes 2,500 gallons or about 10 metric tons of water to produce one pound of beef.   

Some researchers have offered an overall estimate that it takes in average about 3,000 liters (or 3,000 kg) of fresh water to produce food of recommended daily dietary need for just one person.  If you assume that fresh water (renewal) cycle is in average 2 years (too short?), i.e., time takes after the consumption of fresh water till it becomes available and is consumed again, and that majority of fresh water supply is from surface, then with some simple arithmetics, the earth should be able to sustain about 7.5 billion people with decent nutrition.  Now you can understand why there are already so many starving people in the world given uneven distribution and local overpopulations.

We haven’t even talked about the connected issue of the availability of arable land and other limiting factors which are required for food production.  The fact is China, India, and many countries have been busy buying and leasing land in Africa to produce food for their domestic consumptions.  This should give you a pretty good idea of what is going on.  We also have not gone into the details of the assumption of the living standards for some of those estimates.  Obviously, there is a huge difference in the per person consumptions of resources for U.S. and for countries like Niger.  With all these considerations, Ross McCluney estimated in his article of How Many People Should the Earth Support? that the planet earth can support about 6 billion people if U.S. and Western European keep their current level of prosperity and the rest of the world live like Mexicans.  Obviously it is too late to debate that as we already past the 7 billion milestone at the end of last month.  He also estimated that the earth can support 20 billion people if everyone lives like Mexicans and 40 billion if everyone lives like people in today’s northwestern Africa.  But would you be ok to live like that? 

Along with the rich resources and information compiled on the EcoFuture web site, one finds two interesting quotes which still ring true today and worth repeating here.  One was by the late Isaac Asimov, a famous biochemist and writer.  In his Oct 1988 interview with Bill Moyer, he said: "...democracy cannot survive overpopulation. Human dignity cannot survive it. Convenience and decency cannot survive it. As you put more and more people into the world, the value of life not only declines, it disappears. It doesn't matter if someone dies. The more people there are, the less one individual matters."  The other is a popular but un-sourced quote by the late Robert McNamara who was the Secretary of Defense overseeing the escalation of Vietnam War and former World Bank President.  He supposedly had said: “Short of nuclear war itself, population growth is the gravest issue the world faces. If we do not act, the problem will be solved by famine, riots, insurrection and war.”  

What McNamara was referring to have been happening in many places at smaller scales including the ongoing Africa Horn as we speak.   The “good” news is if the problem is not addressed soon enough, it will be solved for us anyway.  Planet earth will continue on for a very long time after you and I died, and with or without humans.  The bad news is the solution is going to be real ugly, much worse than the often criticized China’s one child policy.  There will be conflicts, famines, wars, and massive deaths as people will be fighting for the little remaining available resources.  Meanwhile the continuing deterioration of the environment and climate change could only accelerate the downward spiral and further reduce the available resources.   By then, it will be too late for the occupants of earth to try to reverse it.   What do you think we should do now?

Presidential Leadership

In the current issue (2011 November 7^th) of Time Magazine (U.S. edition), Chris Matthews wrote a 2,000+ words feature article, entitled Five Things JFK could Teach Obama.  Chris Matthews is an outspoken and articulated political commentator.  He is an avid admirer of President Kennedy.  He was very enthusiastic about and having had high expectation of President Obama during last presidential election in 2008.  

You may or may not agree with Chris Matthews political views or may or may not support President Obama.  But the article does make excellent observations about what are missing in President Obama’s leadership for wanting to be a transformative president.  Such insights are useful for leaders (and those aspired to be a leader) in general.  Equally important for those who care about the future of Taiwan, much of Chris Matthews’ unsolicited advices for President Obama are strikingly useful to President Ma of Taiwan, ROC as well.   Since the full article is not accessible without a Time Magazine subscription, I summarize and discuss it below. 

The five things Chris Matthews wants President Obama do are:

1)You’ve Got to Ask Chris Matthews starts with the frequently quoted phrases of Kennedy’s 1961 Inaugural speech "Ask not what your country can do for you - ask what you can do for your country".  He expands it further and points out that the president cannot do it alone, and must ask and invite his fellow citizens to join him and to follow him with specific actionable programs.  Chris Matthews clearly feels disappointed that President Obama had stopped at asking people after the election and left his enthusiastic supporters watching at sidelines.  His advice for President Obama is simple: start asking.

2)Create a Political Band of Brothers and Sisters Chris Matthews notes that Kennedy had forged a team of confederates including capable young lieutenants who are middle class to the core.  In contrast, he has not seen President Obama forge bounds and only see “a band of political neutrals” around him.  He can’t stop wondering who would speak up for Obama with real passion these days when things get tough.  Chris Matthews also relates a story that says it all: a congressman told Tip O’Neill (who was the Speaker of the House from 1977 to 1987) that he couldn’t stand with him on a tough vote and that “I’ll vote with you when you’re right”.  O’Neill responded “I don’t need you when I’am right”. 

3)Take Responsibility Chris Matthew points out that President Kennedy took the personal accountability for the disastrous Bay of Pigs Invasion.  People in fact responded positively to the admission as reflected in the approval rating polls.  Learned from that mistake, a year later, President Kennedy resisted the push by Joint Chiefs for air strike or full scale invasion and successfully resolved the Cuba missile crisis peacefully.  President Obama needs to take the heat and explains why 2009 stimulus bill has not achieved what he said it would for the economy and unemployment.

4)Believe! Chris Matthews points out that President Obama himself has recently quoted from Kennedy’s 1963 American University speech “… Our problems are man-made; therefore they can be solved by man.”  He reminds President Obama the most powerful emotion of American people – the astonishing optimism and the can-do resilience.  He advises President Obama to tap into that emotion by pointing to the victories such as the turnaround of auto industry and brining Osama bin Laden to justice.

5)Show the Vision Chris Matthews reminds all of us that “we knew what Kennedy wanted to do, where he was going.  He showed us his dreams right there in his programs: the peace Corps, the space program, nuclear-arms control.”  Chris Matthews suggests that “what is missing now is a spirit of adventure, of common purpose, a positive feeling, even romance about the times for meeting the challenges in the world, a stirring national cadence, a sense of mission.”  He asks “what are Obama’s dreams?  Where would he take us?”  and “Tell us, Draw a picture. Throw a cap over a wall.”  The last metaphor is especially important.  It came from President Kennedy who related a story of how little Irish boy would get themselves climb over orchard walls by first throwing their caps over.   Only with that level of commitment and risk taking, can one hope for a complete success.

For those who are familiar with the politics of Taiwan and President Ma Ying Jeo’s leadership, I am sure now you can see the similarity and understand why I thought Chris Matthews’ advices are relevant for President Ma.   How many times have you felt that no one is speaking up for President Ma with real passion?  Where is he taking or wants to take the people of Taiwan?  Why hasn’t he admitted to major mistakes and taken personal responsibilities? Why hasn’t he shown his confidence and tapped into the resiliency of Taiwan people?  Why hasn’t he forged any alliances?  Why is he standing alone and hasn’t asked people be with him and follow him with actionable programs?  My advice to President Ma is he needs to read this Chris Matthew’s article, NOW!