Light, Color and Perception

“If one says ‘red’ – the name of color – and there are fifty people listening, it can be expected that there will be fifty reds in their minds. And one can be sure that all these reds will be very different.” “We never really perceive what color is physically.”

(Josef Albers, American-German artist)

Jonathan, a 65-year-old artist, is involved in a car accident. While driving, he is hit by a truck on the passenger side. He is taken to the emergency room, told he had suffered a concussion, but that it did not appear serious. But then something peculiar happens. While taking an eye exam, he discovers that he is unable to distinguish letters or colors. Letters seem to be Greek and images look like a black and white television screen. “My brown dog is dark gray. Tomato juice is black.” Eventually he is able to see letters as before, but he can never see colors again.

His condition is called cerebral achromatopsia, a type of color-blindness caused by damage to the cerebral cortex. Jonathan’s eyes are fine, but his brain is not. The accident caused irreparable damage to a part of his brain responsible for processing color, a small area of the visual cortex called V4, located in the rear of the skull.

Jonathan’s story illustrates the concept that color vision is humans’ perception of a physical phenomenon that must be interpreted by their brains. Josef Albers’ quote highlights how different this experience is among individuals. To fully understand this complexity, we first need to understand the nature of light and color.

Physics defines the word light in a slightly different manner than our everyday use of it. Physicists refer to light as the entire range of the electromagnetic spectrum. Radio waves are at the low-energy end, while x-rays and gamma rays are at the high-energy side of the spectrum. Between these two extremes there is a narrow range which is referred to as visible light. Visible because it can be detected by our eyes. This is what most of us call light.

All light, including the visible one, is made of subatomic particles called bosons, specifically some called photons. You may remember recently hearing in the news about the discovery of the Higgs boson, more commonly referred to as the “God particle”. Photons are a more common type of boson, a bit less glamorous. We can think of photons as massless small packets of discrete energy or what physicists called quanta of light. Quanta from Latin meaning amount, in this case meaning the smallest possible discrete unit of energy. Photons are the force carriers between electrically charged particles, like protons and electrons.

The difference between a radio wave and what we perceive as Red is just the wavelength or energy level of the photons. The longer the wavelength, the less energy the packet contains; the shorter the wavelength, the higher the energy. The amount or quanta of energy is determined by a simple formula consisting of the wavelength times a constant. We could say that what we perceive as Red is just a higher energy photon than a radio wave. What our eyes perceive as light are all the photons within a range of wavelength or energy levels that correspond to the visible part of the spectrum. What we perceive as different colors really are just photons at different wavelengths or energy levels in that spectrum. Red light is the longest wavelength and lowest energy level, while violet corresponds to the shortest wavelength and highest energy level.

The following charts show the entire light spectrum and where visible light falls in, around the middle section, between infrared and ultraviolet. Also take a look at the factors of scale, frequency and temperature.

By Inductiveload, NASA – self-made, information by NASABased off of File:EM Spectrum3-new.jpg by NASAThe butterfly icon is from the P icon set, File:P biology.svgThe humans are from the Pioneer plaque, File:Human.svgThe buildings are the Petronas towers and the Empire State Buildings, both from File:Skyscrapercompare.svg, CC BY-SA 3.0,

The Sun is a mass generator of photons. It generates them across the entire electromagnetic spectrum from radio waves to gamma rays. It spits them out in all directions into space. Let’s  follow a single photon’s journey, it has a wavelength that most of us perceive as the color green in the range of 560–520 nm. Let’s say that our photon is traveling along with a group of other photons. This group consists of photons in a continuous range of wavelengths in the visible spectrum. This means that some would correspond to what we perceive as the color red others yellow, orange, blue and violet. Our eyes would perceive this mixture as just white light. The group leaves the surface of the Sun and about eight seconds later they start striking the suspended particles of gases in our atmosphere, then the surface of the earth, a mountain, a rock, a tree, a leaf and so on. This is when things start getting interesting.

There are basically three things that can happen to these photons: their energy can be absorbed, reflected or transmitted. What happens depends on the atomic composition of the objects they strike. Every element in the periodic table responds differently to each wavelength or energy levels of photons. The reaction depends on the natural frequency of the electrons within the atoms. Because of this property of matter, every element in the periodic table has a distinct color signature. This property is used in spectroscopy, using light to determine atomic composition, and it is widely used in many areas of science.

In the case of the leaf, its atomic composition absorbs the energy of most of the group of photons, except for our photon.  That photon has a wavelength which corresponds to what we perceive as green. The leaf reflects that single photon which then strikes a cone cell in our retina in the back of our eye and we perceive the leaf to be green. In reality, it will take much more than a single photon for us to be able to perceive light or color, but it is a simplified example of how the process works.

If you have not noticed by now, I have been using the phrase “we perceive” several times when referring to color. This was a conscious effort because a lot of what we call color is based on perception. Our vision can be thought of as the psychological perception to a physiological response of visible light waves. That is a real mouth full, I know.  Simply, psychological perception refers to what happens in our brains, while physiological response is what happens in our eyes. Speaking about the brain’s process, or the psychological perception of light, Dr. Dennis Eckmeier, explains it best:

Perception itself is an inner process that has only little to do with the physical phenomenon. We don’t feel temperature as the movement of molecules, we don’t see light as electromagnetic waves but as colors.”

In other words, our response is not in line with the actual physical phenomena but an abstraction or construct of our minds.

But what about the physiological response, or more specifically, what happens in our eyes?  Eyes are the transducers or the brain’s translator of light, what eventually results in our perception of color and vision. It is estimated that most humans can see around one to two million colors. There are some people, particularly women, who may be able to see up to ten million colors. Let’s not mention other species that can see far more colors, like the zebra finch. Or even others, such as the arctic reindeer, who are able to see other parts of the spectrum, like ultraviolet light. How is that possible? How is their eye structure different from ours? How do our eyes translate light, an electromagnetic wave to something that our brains abstract to color and vision? What are the limitations our eyes impose on vision and color perception? We will continue to  explore this part of the puzzle in an upcoming segment.

The Hidden Side of Success


Gary Monroe Lecture at FIU


“Failure is just one more iteration toward success.”

We hear this type of talk all the time, well at least I do. But the question is why is this so? Why are people so eager to embrace failure in all of its forms? Well because failure is embedded into their system of  thinking about success .

Last week I attended a lecture by photographer Gary Monroe where he discussed  his body of work on Miami Beach and Haiti during the late 70’s through the 80’s. During his talk he explained that he had shot, and actually still shoots, in black and white film. Most of the shots he takes don’t really come out right for what ever reason, he uses up a lot of film to just get in a few good shots. He gave out some percentages of what he thought was his ratio of good to bad shots something like 20% are shots he can use, the others not. Lets think about this, he fails 80% of the time, wow 80%.

Same thing happens in software development. Many times a brute force algorithms is used to solve some problems. Brute force meaning, just try as many possible combinations and see which one gets close to an acceptable answer. This is the way many early calculators would solve math problems, basically guess until you get close. As you can see failure is built into the solution, you must fail many times to succeed. Failure is hidden in the success.

However, the calculator does not show you how many guesses it took to get an approximation to the correct answer, it just shows you the correct answer, and every one is happy. The guessing is done behind the scenes at lighting speed by the processor, almost instantaneously, as far as we are concerned. Just like you don’t see 80% of the bad shots that Gary takes, we only see a fraction, the 20% , the good ones.

Because failure happens behind the scene we don’t get a real appreciation for what it takes to succeed.  We may think that its easier than it actually is, and when we are hit with our first roadblocks or first failure we think something is wrong, that we are not good enough or that our idea is not good enough. Real life is a bit messy and we don’t iterate at lightning speed, our feelings and emotions sometimes get the better of us. We all are afraid to feel the sting of failure, but we must be courageous  enough to move forward despite our fears. But the lesson is real, we must try many times, basically the brute force algorithm, at solving a problem to get it right. Think of Edison’s battery experiments, it involved over 10,000 experiments with different chemicals and materials to develop his alkaline storage battery.  When asked he said; “I found 10,000 ways that the battery did not work”.

So in short, lets keep on trying, moving forward through the adversity, the failures, we will succeed if we do not give up, as failure is the hidden side of success.


Gary Monroe, is professor of fine arts and photography. The author of numerous books, including The Highwaymen. Also featured along with Andy Sweet in the documentary “The last Resort”



Cubist Photography

David Hokney most likely known as a painter but he did photography as well. His photography tries to capture multiple perspectives kind of like a cubist painters.

I  have become very interested in this concept, as I think that truth and reality are both relative and can be experienced from infinite points of view. that being said here is the link  to interview with Hokney where he discusses his thoughts on his photos.




Capturing time

Photos allow one to share a moment in time regardless of  physical locations, to share the human experience.

To share a moment in time, how long of a moment and how does this actually occur? To do this a photo always captures the temporal dimension  in the form of shutter speed, in other words how much time is the light allowed to shine on the film or these days sensor. This time is usually in short spurts from fractions of a second for most pictures to sometimes minutes for those very long exposures.

I always been fascinated about the freezing of this temporal moment on the frame, or in other words how much time you actually captured on a single frame of film or in a digital file. But how about capturing even more time on a single frame say hours or days and compressing it to comfortably fit. This is what artist and photographer Stephen Wilkes is doing with his most recent project “Day to Night”.

See him talk about it in this recent Ted Talk.

Thoughts on Fine Art Photography

It seems that everyone has a thought on what fine art photography should be and the problem is that each one is a bit different.

My own thoughts:

Fine art photographs are an expression  of the artist vision in the photo medium, as a canvas to a painter or a piece of clay or stone to a sculptor.  This expression could be carried out anywhere in the workflow of the medium, from the actual composition and subject, to the processing technique used, as long as it is meant to express the artist vision for that particular piece.

Here are a few of my favorites fine art photographers, even though some of them may not consider themselves as such:

Cover Magazine

Winter Copse
Lost Pier
Shard of Light
Venice .,.

Long As I Can See The Light

My philosophy on photography

The success of an image does not solely depends on its artistic or technical merits but how many thoughts it provokes, how it makes us feel, how it stirs our emotions, how it ignites our imagination and passion, how it may change us is some way.

Photos allow one to see the world through someones  lens, it is a reflection of their mindset, their interpretation of reality. They allow one to travel to far away places and share that experience and be inspired. Photos allow one to share a moment in time regardless of  physical locations, to share the human experience.