Color constancy and why some of the science is wrong

I am definitely not going to disagree with the science of color constancy, which dictates that the perceived color of an object remains constant despite changes in light. I am disturbed, however, by the insistence of some neuroscientists that color constancy and the way the brain simplifies color information cannot, under any circumstances, be disregarded or compromised.  Obviously, in their quest for fundamental rules, they are overlooking the possibility of variables in the science of vision. They are discounting the possibility that some people, especially artists, can learn to evaluate the color of the illuminant or light source and in turn learn to evaluate color more accurately.

Color constancy is a feature of color perception which ensures that the color of an object will remain relatively constant under varying illumination. Color constancy explains why the grass in your front yard looks green under blue sky, remains green under a cloudy sky, and still looks green during a red sunset. A yellow banana will always look yellow, despite any change in the light which illuminates it, and a red apple will always look red. Without the brain’s ability to discount varying light conditions, acquiring color information about objects would be difficult. Without this ability to stabilize visual information, the world would be a very confusing place.

The subjective nature of color constancy accounts for the fact that beginning artists often have a hard time seeing color. Shadows will simply look gray, and the yellow banana will be the same color yellow from one end to the other. Beginning artists are not likely to see variation in any local color or be able to adapt to changing light conditions. The idea of cooler north light vs. using a warmer studio light would be confusing. However, the ability to decipher variations in illuminants and to perceive the ensuing changes in the color of objects and the color of shadows can be learned. Most art teachers are going to know this, and so will many painters. At some point, with persistence and practice, we learn to see differently.

Can we learn to totally discount color constancy? Probably not. But we can and do learn to work with it, and in many cases we can learn to see beyond the visual system’s preference for predictable color.

We need to understand that color information relayed to the brain is dependent on the evaluation and comparison of the range of wavelengths of light reflected by different objects in the visual scene. This process allows the brain to estimate and dismiss the influence of the light source and assign a constant color to an object or surface. Color constancy is one of the many “programs” running in the background of our visual system.

The Fisherman by Joaquin Sorolla

So, how do you work around this preference for consistent color? Compare, compare, and compare. Ideally, one should evaluate the quality of the illuminant first. Is the light warmer or cooler? Compare a lit area to a shadow and decipher the difference in color temperature. Next, identify the value range. Find the lightest light in the area where you are looking, and then compare to the darkest dark. Try and grasp the relationship of the two by making a mental comparison to a value scale. Is the lightest area close to white? Or a step or two away from white? Do the same with the darkest value, comparing it to black. This is the beginning of using a different form of visual processing. View the scene as a whole, and then pick out the most obvious differences in the pieces of information contained in the whole.

Now do the same with the colors you are seeing. Look for the “warmest” color notes, those more closely aligned with red, orange and yellow, and then compare with the “coolest” information, blues, greens, and violets. Look for the most obvious differences and then try to assess the more nuanced information. Remember that this is an ongoing process and not a once-and-done thing. Once you stop looking for differences, and once you stop comparing, you will revert to normal visual processing.

And some of the neuroscientists? Well, it seems as if many don’t think artists can learn to use the brain’s ability to process and compare complex information in a different way. They don’t believe we can learn to see differently. I think this bias is compromising the integrity of their research. Believing seems to be the first step in acquiring new information. Learning to see differently comes from a place of knowing this is possible.

The Rouen Cathedral series was painted in the 1890s by Claude Monet. The paintings in the series each capture the façade of the cathedral at different times of the day and year. The cathedral allowed Monet to highlight the paradox between a seemingly permanent, solid structure and the ever-changing light which constantly plays with our perception of it. 

Four ridiculously simply ways to improve your painting

1. Stop and Look
Yes, I know this one sounds obvious, but after 25 years of teaching workshops, I can tell you the most common mistake artists make is to quit looking. I’ve seen far too many artists veer off into trite and predictable painting after a good, strong start simply because they stopped looking at the subject and the canvas with a critical eye.

This is often the result of what I call “brush-overdrive” which basically means a person will move the brush around on the canvas just because the brush is in the hand. We could also call it “automatic painting” - something similar to automatic writing which is defined as writing without conscious thought. Although we would all probably like some painting spirit hovering overhead telling us what to do next, count that option as not available and deal with the choices at hand. Just because there is a brush in your hand does not mean you actually have to make a mark on the canvas. Moving the brush and actually putting paint down do not always have to go together.

Develop new habits for looking and painting. Try not to make more than 3 or 4 brushstrokes at a time without stopping or pausing to observe. This gives you a place to use some critical thinking and observational skills before returning to the more creative brush mark. Find your own rhythm, but make sure you are not making multiple brush strokes without intent and without stopping to look.

2. Stand comfortably with a good view and remember to step back
Find a comfortable stance in front of the easel that allows you to easily move or alter your stance. (For those artists who sit while painting, try a chair with casters.) Avoid a rigid, fixed stance that prevents you from adjusting your view of the subject and of the canvas.

Even more importantly, stand at a distance that allows you to see all four corners of the canvas. We have a tendency to paint “things” without regard to the spaces around the “things.” Getting in the habit of seeing the entire canvas makes it easier to recognize that each mark and each shape has a relationship to the whole. Staring at pieces of information is an entirely unnatural act. In our everyday lives our eyes are constantly moving so keep that in mind next time you find your nose inches away from your painting.

Stepping back from the painting is not just an exercise program for painters. At one time or another, or maybe more often than we care to admit, we have worked feverishly on a painting only to walk away and realize there is no “there” there. The values and color are nondescript and perhaps the drawing information went awry. Standing in a fixed position and staring at pieces of information is not conducive to incorporating all those pieces into an interesting whole. Moving away from the canvas (or yes, even to the side) on a regular basis allows a different view and is more similar to how we naturally see the world around us.

 Also, if you are working on a large canvas, you will need to step back to be able to see the whole of the canvas – all four corners of it. John Singer Sargent would back all the way across the room to view his life-size paintings and then run forward to make a brushstroke.

3. Squint!
Take off your glasses, close one eye, squint, or look sideways, but alter how you are looking on a regular basis.

Squinting is the best for value comparison. (It is not good for color comparison.) Squinting simplifies the information and allows us to see patterns more easily. Finding an interesting and strong value pattern is often the foundation for the entire painting.

Closing one eye eliminates depth perception and flattens the image.

Looking sideways or peripherally is an important, but unsung, part of our visual perception. Only the very center of our gaze is optimized for higher visual acuity with the ability to see detail. We don’t usually notice this because we are constantly moving our eyes. This does not mean the rest of our visual field is inferior – only different. Peripheral vision is optimized for coarser information and is used for organizing the spatial scene and for viewing larger objects. Margaret Livingstone in “The Biology of Seeing” suggests peripheral vision is better able to detect facial expressions, and that the spatial imprecision of peripheral vision was an important component of many Impressionist paintings, giving these paintings a sense of time and movement.

4. Mind your brushes 
Use the right size and type of brush for the task at hand. The paintbrush doesn’t just define information – it creates it. Whether you need texture, or shape, or definition use the proper brush and don’t just default to the one already in your hand.

Pay attention to how you are holding the brush. While there may be occasion to hold the brush like a pencil, recognize this method is not as conducive to creative and interpretive painting and it is also not likely to create variety and interest in your brushstrokes. Handling the brush like a pencil or pen is most likely to access the neural pathways in your brain that are associated with language and writing. For the sake of simplicity we can call this a left-brain, right-brain problem. The cognitive processes associated with language can easily override visual processing – the parts of your brain that can recognize shapes, compare value and color, find the pattern, and see the whole instead of just the pieces.

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The creativity crisis

American creativity scores are declining. Research by Dr. KH Kim, Associate Professor at the College of William & Mary, documents a decline on creativity tests at all grade levels starting between 1984 and 1990 and decreasing ever since.

Kim’s findings document a decline in all aspects of creativity, but the biggest decline is in the ability to take a particular idea and expand on it in an interesting and novel way. More than 85% of children in 2008 scored lower on this measure than did the average child in 1984. According to Kim, “children have become… less perceptive, less apt to connect seemingly irrelevant things, and less likely to see things from a different angle.”

So what exactly is creativity and why are we having such a problem with it? First of all, creativity is certainly not just the domain of the “arts”. The University of Georgia’s Marc Runco calls this “art bias.” The continuing belief that the arts have a special claim to creativity is unfounded. When given creativity tasks both engineering majors and music majors had the same patterns of response.

Creativity is not just right brain dominance; it is the ability of the brain to discern information from both hemispheres and to use convergent and divergent thinking (such as linear and non-linear thinking). Trying to solve a problem with only the right side of your brain would result in ideas on the tip of your tongue and just beyond reach.

The initial process of problem solving begins with the left brain analyzing obvious facts and familiar solutions. If the answer is not available, both the left and right hemispheres activate together to process the less obvious information. This more distant information is what we normally tune out, and without it we are less likely to find abstractions, unseen patterns, and alternative meanings. Once a connection is made, the left brain then processes the information into a new idea. Without the process of divergent thinking, using both hemispheres of the brain, we are completely dependent on only the most obvious and already recognized thoughts and ideas.

Unfortunately, many people are uncomfortable with the change and uncertainty that accompany creativity. It is easier and more comfortable to deal with what we already know (and think we see). According to Kim, the “decrease in originality scores is an indirect measure of growing social pressures toward conformity and status quo, and increasing intolerance for new ideas.”

“Yes, There IS a Creativity Crisis” by KH Kim Jul 10, 2012
“As Children’s Freedom Has Declined, So Has Creativity” by Peter Gray, Psychology Today Sep 27, 2012
“The Creativity Crisis” Newsweek Jul 19, 2010

"The Lemon" by Euan Uglow

Dome at Volterra

Euan Uglow described to an interviewer the inspiration for his still life Lemon (1973):

"I'll tell you what Lemon is about ... It's the dome at Volterra that Brunelleschi was supposed to have helped with. It's most beautiful, very simple, very lovely. I couldn't paint the dome there, so when I came back I thought I'd try to paint it from a lemon."

"The Snail" by Henri Matisse

Henri Matisse gave up painting in the last years of his life to create paper cut-outs. These were made by cutting or tearing shapes from paper which had been painted with gouache. Matisse said the technique allowed him to draw in color. His daughter said her father made many drawings of snails at the time of the work “The Snail” (1953) and that the idea for this work came from these drawings. The concentric pattern formed by the colored shapes in the center of the work echoes the spiral pattern found in the snail’s shell. 

Matisse said, “All this time I have looked for the same things, which I have perhaps realized by different means . . . There is no separation between my old pictures and my cutouts, except that with greater completeness and abstraction I have attained a form filtered to its essentials and of the object which I used to present in the complexity of space, I have preserved the sign.”

Disney meets Sorolla

A while ago as I was trying to explain the concept of warmer-cooler color to a group of students, I could tell some of them just weren't getting the meaning of color pattern. The next morning, while reading the morning paper in my hotel room, I came across several images from a Disney animated film. They were excellent examples of design with color temperature. A frame would be either primarily warm or primarily cool with accents of the opposite color temperature.

 I clipped the pictures from the paper and took them into class. As I held the images up and explained the use of color it was apparent this example made an impact. Why? Because the images were simplified and the colors were easy to identify. They used basic color notations and were easily seen as primary and secondary colors. And once the identification of color was made, it was just as easy to see the pattern of warmer-cooler colors.

Understanding color temperature is complicated by the fact visual experience and, in turn, most paintings are composed of subtle variations that have little resemblance to a color wheel.  It is difficult to compare a grey or tan to a primary or secondary color. But if we learn to identify the most obvious information first, deciphering the rest of the visual information becomes just a little easier.

William F. Reese gave his students good information when he instructed them to: 1. identify the hue – red, yellow, blue or green; 2. adjust the value which is often to lighten by adding white, then adjust the temperature by using adjacent hues from the color wheel; and 3. adjust the chroma (intensity of the color) by using the complement if necessary.

I can’t say I am as directional nor as organized to follow this method of color mixing, but it certainly helps clarify the process.

The work of Joaquin Sorolla (1863-1923) provides some great examples of color temperature and the pattern of color information. Many of his paintings have a clarity of color and a pattern of warmer-cooler color that is reasonably easy to identify.

Promenade on the Beach by Joaquin Sorolla

Children on the Seashore by Joaquin Sorolla

Child's Siesta by Joaquin Sorolla

Chalk and mud

When an artist refers to an area in a painting as looking chalky or muddy, the problem is usually color temperature.

 “Chalky” refers to white without a specific and appropriate color temperature and “muddy” is probably a darker value without a color temperature. The problem is most likely paint without an identity – something akin to limbo, neither here nor there. This does not mean every bit of paint on a canvas needs to resemble a color wheel of primaries. Just a nudge here and there will identify a color as warmer or cooler.

Highlights and areas of very light values should have variation and interest. A touch of viridian or orange can do wonders for highlights, and larger areas of light value need to have an identity other than “white”. They need to be part of the overall pattern of color temperature but still be descriptive and interesting.

The problem with “mud” usually begins on the palette, but over-brushing an area of a painting will also mix the paint into one non-descriptive mess. The problem is not because the artist mixed more than three colors together on the palette. This “rule” arose in an attempt to find an easy solution to non-descriptive mixtures. Perhaps it works for some, but I am in the camp of sometimes scraping paint on my palette into one big pile and using it (and this is the important part) if it is appropriate and useful. This mixture of multiple colors might need some adjustment for value and color – lighter, darker, warmer or cooler.

Neutral mixtures of paint (tans and greys) are important. They enhance and help identify color. All areas of a painting do not need exclamation points. Just learn to appreciate subtle changes in color and pay attention to the overall pattern of lighter and darker values and warmer and cooler colors.

Do you see blue like I see blue?

For various reasons it is quite likely we don’t see color the same. The names for the colors of the rainbow are arbitrary constructions. The Russian language, for example, has two separate words for the color “blue” found in the rainbow. Most of us have just one word for the same color. Does this make a difference in how we “see” the color?

Recent experiments have shown that if we have a name for a color, we are quite likely to see it in a different way. Naming and seeing are connected and what we see changes according to whether or not the language centers of the brain are activated. (The Secret Language of Color)

The language of color differs depending on where you live. There are evidently still tribes that don't have color names beyond black and white. It is also interesting that the naming of colors across all cultures has a distinct pattern. Black and white are always the first to be named. Red is next. After that, there are variations in the naming of color, but usually yellow or green follow, then blue or violet. Colors such as orange and pink appear later.

The colors of the rainbow have changed over time. As late as the twelfth century, the arc was portrayed with only red and green and a band of white in the center. The rainbow didn't take on additional hues until the Renaissance, and it wasn't until the eighteenth century and Newton that we acquired the colors of the rainbow as we know them today. And then there is the Russian language which has two words for blue, “goluboi” for light blue and “sinii” for dark blue. This distinction is similar to the English language separation between pink and red.

Not having a name for a color does not mean a person can’t see the color. Linguists spent two centuries arguing about whether or not a person who didn't have a name for a color could actually “see” the color. We know now that is not true. We are starting to recognize, however, that the complexity of visual processing is both enhanced and inhibited by the language centers of the brain.

"The Secret Language of Color" by Joann Eckstut and Arielle Eckstut
"Through the Language Glass: Why the World Looks Different in Other Languages" by Guy Deutscher

More interesting stuff - robins actually see the earth's magnetic field!

Something about color

The easiest way to understand color is to review Isaac Newton’s experiments with light in the late 1600s. He was the first to understand the rainbow when he refracted white light (sunlight) with a prism. When the light passed through the prism it scattered the different colors of light according to their wavelength, showing a continuous band of colors – violet, blue, green, yellow, orange and red, (Newton included indigo which would have numerically aligned his color diagram with the seven tones of the musical octave.)

Newton then turned that band of colors into a circle and created the color wheel. Up until then, for over two thousand years, color theory was dominated by Aristotle’s version of linear color which was arranged from white to black, with red in the middle, yellow next to white, and blue next to black. Obviously, Aristotle’s version was more of a value scale than a color diagram.

However, while the color wheel has its advantages in recognizing color relationships, such as complementary, analagous, and secondary colors, it also spawned multiple variations, numerous color theories and a lot of confusion for artists.

So let’s go back to the rainbow and the science of color – the band of colors discovered by Newton when he separated sunlight into wavelengths of light with a prism. Color is a property of light. The wavelength of visible light has a pattern. It is a range of color from violet to red. It is dictated by the wavelengths of the spectrum. The colors do not jump around at random. Just as value has a pattern of light to dark (shadow), color also has a pattern. Red turns into orange, which then turns to yellow, then green, blue, and violet. This is the pattern of visible light. Objects have no color of their own; they only have the ability to reflect certain rays of light.

The other pattern of visible light is what we can observe as color temperature. This is not an absolute value, never just warm or cool, but an “as compared to” value – warmer or cooler. The pattern of visible light, violet to red, ranges from cooler to warmer. Blue is seen as cooler than red, but ultramarine blue has elements of red color and is seen as warmer than cerulean blue. Alizarin red, which leans towards violet, is seen as cooler than cadmium red which leans towards yellow.  Understanding warmer and cooler colors is based on recognizing the importance of comparison and being able to see if a color tends towards red and/or yellow, or if a color leans towards blue and/or green. Trying to establish an absolute value with color temperature is confusing and misleading.

And now we need to understand that the quality of the light (warmer or cooler) modifies everything. As light changes, color changes, and our perception of color can change with the surroundings. Identifying the light source as either warmer or cooler will simplify the visual information and help us to observe, quantify, and mix colors. Cooler light (such as a cloudy day or early morning) means warmer shadows. And, please note, I did not write “warm” shadows.  A shadow is an absence of light and that same light has color information, so a shadow is an absence of that color information. That does not mean one cannot see a variation of color temperature within a cooler shadow. The real world is a combination of direct light, ambient light, local color, reflected color, etc. Identifying color is a process of comparison – warmer, cooler, lighter, darker.

To keep everything in perspective, we need to recognize that the science of light and color is different than the science of pigment and color. The former is additive and the latter subtractive. Add all the colors in light together (as Newton did after he first separated the colors with a prism) and you will have white light. Do the same with pigment and one will end up with black – or if you are an artist, something akin to “muck”. There is no such thing as the “right” color – only the color that looks right.

Also, the human eye can distinguish up to 10 million colors. Since the brain is the processing component for determining visual information, and the brain assesses information based on experience and knowledge, then it is safe to say that we can see colors differently. Ultimately, the whole idea of painting “things” is an illusion, smoke and mirrors, merely one person’s impression and interpretation of visual information. Somewhere other than trite and predictable is a place of creativity and discovery.



“Color is life; for a world without colors appears to us as dead. Colors are primordial ideas, children of the aboriginal colorless light and its counterpart, colorless darkness. As flame begets light, so light engenders colors. Colors are the children of light, and light is their mother. Light, that first phenomenon of the world, reveals to us the spirit and living soul of the world through colors." - The Elements of Color by Johannes Itten

While the history of art is a study of changes in the use of color, the Impressionist painters are notable for their study of sunlight and how it alters the local tones of objects. Monet explored these changes methodically, sometimes requiring a fresh canvas at each hour of the day. The best examples of Monet’s exploration of sunlight and atmospheric color changes are his series of Rouen Cathedral paintings.

Interaction of Color by Josef Albers - a highly regarded book by one of the most influential artist-educators
Color by Betty Edwards - instructive and informative
Color: A Natural History of the Palette by Victoria Finlay - interesting, engaging book, part travelogue, part history 
The Rainbow Goblins by Ul De Rico – a classic story with beautiful illustrations for the child in all of us.

Anderson workshop - a short version

I just returned from teaching a workshop in Fredericksburg, Texas. It was great to see a few old friends and meet some new ones. I was privileged to again work with a great group of artists. One of those artists is also a very talented writer. Ruth Heffron surprised and awed us all with her poem about the workshop. We laughed and nodded in agreement when she read it aloud while I was doing a demonstration. Everyone agreed she nailed it. I, for one, will try and pay a little more attention to not just what I say, but how I say it!

Maker's Mark

by Ruth Heffron

SURPRISE YOURSELF
MAKE LIGHT TOUCHES, LITTLE MARKS.
FLYING TRIANGLES, ANGLES OF REPOSE
ARE YOUR BEST FRIENDS TO MOVE YOU
THROUGH. LOSE YOUR EDGE. MAKE
NEGATIVE SPACE.

HOLY CRAP, WE'LL HAVE NO BASKETBALL
HEADS NOR FRIGGIN' CONTOUR
DRAWINGS! REALLY?

MAKE INSTEAD YOUR "you are here" MAP
GET IN THE BALL PARK AND KEEP
ADJUSTING YOUR
  LINE  SHAPE  VALUE  COLOR



Ruth Heffron Fine Art

Everything you need to know about painting

1. The Art of Seeing - Squint!
2. Design & Composition - Think cause and effect.
3. Everything You Need to Know About Values - Is it lighter or darker?
4. Everything You Need to Know About Color - Is it warmer or cooler?
5. When Your Painting Doesn't Work - Identify the problem and find a solution.
6. When Your Painting Still Doesn't Work - Take a break. Drink coffee. Read No. 5.
7. It Still Doesn't Work - Never beat a dead horse.
8. How To Know If Your Painting Is Finished - You have a run out of time or have nothing else to say.

Artists Paul Mullally and Ned Mueller taking a break from painting.

Why naming the "thing" can be a problem

Look at one or the other of these two well-known optical illusions and notice how quickly you can change the image by saying either duck-rabbit or face-vase.

The duck/rabbit and face/vase illusions are well-known examples of ambiguous information. Seeing is a "best guess" based on the information at hand. In these examples the visual information presents alternative interpretations so we see first one image, and then the other. We don't see the shape apart from the interpretation. The “naming of the thing” simplifies the process of trying to decipher the visual information.

Visual ambiguity is not just confined to optical illusions. Vision is a process, not a picture. We see what is most different and usually group together what is most similar. We see the obvious changes and make assumptions about what we see based on what we know and what we expect to see. ("Vision and Art" by Margaret Livingstone) It is important to understand how seeing can be compromised by knowledge, expectations, and also language.

When we "name the thing" we are more likely to see what we think we know about the object. We are less likely to see its specific and accurate attributes, such as shape variation, color, value and edges. There are varying levels of visual accuracy and artists need to be able to combine the knowing and the seeing. At times it is important to be able to see without the preconceived information of the "knowing." That is why some artists may view reference material upside down. It takes the information out of context and makes it easier to see the relationship of shapes, colors and values.

Realist painters paint “things” – ordinary (and maybe not so ordinary) objects, people and places. Realist painting has certain parameters and an obligation to reflect some aspect of a universally accepted reality. It may be easier to see “things” than it is to see structure, order and how visual information is related. But these are just two different ways of seeing.

Realism can also be about possibility – the possibility of vision and personal expression - the possibilities inherent in using value and color and making marks. Never underestimate how "naming the thing" can compromise the integrity of the visual information.

Do you really want to paint what you already know? Or do you want to know and see something in a different way?

“I don't paint things. I only paint the difference between things.” Henri Matisse