Eye tracking the stairway illusion

When I painted this Dinotopia image I wanted to do my own spin on the famous "infinite stairway" optical illusion invented by Lionel Penrose and M.C. Escher.

If you walk around the stairs clockwise, you proceed infinitely downstairs, and if you walk counterclockwise, you go upstairs forever without gaining in altitude.

"Scholar's Stairway," Oil on board, 12 x18 inches.

The way I painted it, the illusion is fairly subtle, and I wondered if other people even noticed the illusion, and if so, whether their eyes moved systematically around the stairs.

To find out, I asked vision scientist Greg Edwards, president of Eyetools, Inc., to run some eye tracking tests using this image as the subject.

Dr. Edwards had fifteen subjects look at my pictures on a computer screen for fifteen seconds each while a sensor tracked their eye movements in real time. Below is the eye track of one subject's experience. The colored line shows the pathway of the eyes, beginning randomly at the green circle. The numbers in the black squares show where they eye traveled at each second of the fifteen second session. 

One can’t know for sure without a follow-up interview, but evidently this particular observer didn’t notice the optical illusion.

The second image shows the "heatmap," which aggregates data from all fifteen observers. The red and orange blobs are the areas of the image received nearly 100% of people's attention. The rider on the brachiosaur took attention away from the central illusion. The dark blue and black areas received almost no attention. 

What can we conclude from the heatmap image? Viewers definitely looked at the figures, wherever I placed them. Beyond that, we can't say much because we didn't design a very thorough experiment. I would love to work with a larger sample size and to gather followup interview data, and ideally collect simultaneous fMRI data set to see if we could correlate cognitive behavior with eye movement. That way we could understand better what happens when people "get" the illusion. If there's any vision scientist who has the equipment and wants to try an experiment like this, please contact me.

This original painting is in the "Art of James Gurney" exhibition at UARTS museum in Philadelphia through November 16.
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Previous posts about my stairway painting:
Credit to Mr. Penrose
Using a Perspective Grid

The McCollough Effect

Note: I'm going to postpone the next book club until the first week of November 

because I've got a lot of traveling coming up in October. 

Optical illusions that produce colored afterimages are fairly common, but there's afterimage phenomenon that's so long-lasting that I won't show the induction image directly on the blog.

It's called the McCollough Effect, and it's basically a pattern of black, red, and green bars. Staring at them for more than a few minutes can lead to afterimages that strangely last for days. Ten minutes of looking at it can affect your vision for 24 hours.

In this video (Link to YouTube video), Tom Scott introduces the phenomenon. The video is safe to watch because the exposure to the image is too brief to cause induction.

On this MoviePilot website you can read an informal description about how it works. Here's a more scholarly presentation. If you want to try it, you can follow instructions on the MoviePilot page or on this flash video presentation. 

But—warning—please only try it if you're willing to experience the colored afterimages for hours, days, or even weeks.

I haven't tried it because I'm in the middle of a painting right now. If you decide to give it a try, please share your experience in the comments. I wonder if red-green colorblind people would see any effect. I'm told that the effect can be reversed by gazing at the original induction image, rotated 90º counterclockwise for half of the time that you spent looking during the initial induction.
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MoviePilot website to see the image
Flash video presentation on a Boston University site that induces the illusion.
Via Design Taxi "This Image Can ‘Break Your Brain’, Change The Way Your Mind Works

McCollough Effect on Scholarpedia -- For scholarly analysis of the phenomenon.

Note: I'm going to delay the next GJ book club about Harold Speed's book on painting until the first week of November because I've got a lot of traveling coming up in October.

Austin Briggs on Sketch to Finish

American illustrator Austin Briggs (1908-1973) says: "When working out an idea for an illustration, it is essential to keep in mind the shape of the finished painting at all times. Otherwise you are likely to develop a composition that simply won't fit the picture space."

"If you become too fond of an unworkable idea you may find it hard to start over on a new approach. The sketch above was sone quite spontaneously for a [Saturday Evening] Post cover. A momentary pose of the group suggested the compositional pattern—sort of a hammock design with the body suspended, so to speak, between the supporting figures at left and right."

"I sketched the idea with great satisfaction, thinking I had the answer to the picture problem." 

"When it came to working out the rough, however, I soon realized that this idea could not be made to conform to space requirements. It was very difficult for me to get this approach out of my head and find a design that would work. If I had kept the shape of the picture in mind from the start, I would have discarded this idea before I became too attached to it."

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From Austin Briggs' Master Course from the Famous Artists Course, 1952

Austin Briggs on Wikipedia

Thanks, Matt Dicke

Plein-Air Concept Art

Here's a tease frame from one of the videos I'm working on called "Fantasy in the Wild."



One of the segments will show how I create a concept painting of a giant robot from start to finish on location at construction sites and fast food alleys. This is the maquette, made of construction foam.

Tacit Knowledge

Blog reader Paul VonZimmerman told me he has been thinking about the concept of tacit knowledge and how it relates to art instruction. He asks, "What are your thoughts on this as someone who has created a variety of instructional material?"

First, a definition: Tacit knowledge is the kind of knowing that is hard to put into words, such as kneading bread dough. The opposite is explicit knowledge, which can be easily transmitted verbally, such as the names and placement of colors on the color wheel. 

Even an expert practitioner may not be able to consciously explain their tacit knowledge. Therefore it may be difficult for them to pass it on to the student through writing, lecturing, or diagrams.

A lot of people use the example of riding a bicycle. People who master the skill often don't know why they turn the handlebars right or left to balance and turn; they just "get" it. Riding a unicycle is a lot like bicycle riding, but in addition you have to apply pressure on the pedals to balance in the forward/backward dimension.

In the case of art instruction, I agree that there are topics that can be transmitted more easily through writing or explanation. Those topics, such as perspective, principles of lighting, theories of color, and strategies of composition, can be taught naturally in a book or a classroom setting. They lend themselves to being analyzed and explained in words and therefore they're suited to transmitting reading or watching a lecture. I focused more on those topics in my books Color and Light and Imaginative Realism.

Learning to paint involves a lot of practical skills that many artists find hard to explain. These skills include color mixing, paint application and stretching a canvas. These topics apply naturally to workshops or videos where you can watch someone doing the action, hear them explain why they're doing it, and then practice it yourself until it starts to become automatic.

One reason I love producing instructional videos is that I can film the whole process as I create a painting, and then in the voiceover, I can verbalize my thinking at each stage. I have done live demos where I explain what I'm doing in real time, but unless I'm demonstrating the same skill over and over, I feel I sometimes have to compromise either the explanation or the painting.

To answer your question, Paul, I don't really like the idea of dividing knowledge into fixed categories of explicit or tacit. The problem with the theory of tacit knowledge as I understand it is the presumption that some skills can't be verbalized. I believe any skill can be explained, especially if it is broken down into steps. Moreover, it must be verbalized, especially at the beginning, if the teacher is really doing their job.

Sometimes teachers verbalize surreal images that help students learn a skill. I heard an equestrian instructor tell her students to imagine a beam of light coming out of their belly buttons and shooting forward between the horse's ears. I suppose it worked better than saying "Sit up straight!"

I learned to ride a unicycle by reading a book. I didn't have a teacher and I didn't know anyone else who rode one. The book broke down the process into a series of steps that I could master one by one until I "had it."

Copying from classic illustrators is a great way to turn appreciation into practice.
These are my copies of Sundblom, Cornwell, Leyendecker and Rockwell. 

When it came to learning art, I never had a formal painting teacher, nor did I watch any art videos when I was first learning. Until I was in college I didn't know any other artists. I learned everything on my own through reading and practice starting in elementary school, so I'm a great believer in the power of the written word.

Rather than conceiving of the universe of learning as divided into two groups of knowledge, tacit and explicit, I think it's more useful to look at learning—especially "motor" or muscle-based learning—as a process of internalization. New studies of the brain have shown how conscious knowledge is gradually made automatic as the neural pathways shift from the outer cerebral cortex to deeper networks in the brain. The theory of motor learning is a rich subject, but let's save it for another post.

In the comments, I would love to hear from art teachers about how you teach various kinds of art knowledge, and from students about what what kinds of teaching has helped you the most in learning to draw and paint.

LINKS
Tacit knowledge (link to Wikipedia)
GurneyJourney YouTube channel
My Public Facebook page
GurneyJourney on Pinterest
JamesGurney Art on Instagram
@GurneyJourney on Twitter

Market Square and Maquette

"Market Square" and the archway maquette I built for lighting reference are both now on view at "The Art of James Gurney" exhibit at the University of the Arts in Philadelphia through November 16.
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My Public Facebook page
GurneyJourney on Pinterest
JamesGurney Art on Instagram
@GurneyJourney on Twitter
More on maquettes in my book Imaginative Realism: How to Paint What Doesn't Exist

Painting a Potter

At our figure sketch group we want to paint a person doing a real action, rather than holding an artificial pose.

Sarah the Potter, oil on canvas, 9x12 inches, 5 hours

So we ask Sarah to bring her pottery supplies and to do her normal work.

We agree on a base pose that she can return to from time to time. We talk to her during the pose, so she's not holding totally still.

1. I draw with the brush on gesso-primed canvas mounted on a Masonite panel. I begin the quick block-in with casein. Casein is a good underpainting medium.  

Right away I'm looking for the big shapes of tone, in this case her light face and figure against the simple dark background.

2. I begin to overpaint with oil on the face, hair, and background. Eventually, about 95 percent of the surface will be covered with oil paint. The oil paint achieves deeper values than the casein because of its glossiness.

I have three cups: Gamsol for thinner, Liquin, and a slow-drying medium (equal parts stand oil, damar varnish, and turpentine). 

3. I simplify the tones in the arm and shoulder and torso, painting them with very little value variation and using color temperature to turn the form instead. 

Consequently, the front plane of her shoulder has a slightly cooler cast. 

The key light is a warm incandescent. I introduce the window into the composition to motivate the cool edge (or "rim") light.

Her hair melts into the simple tones of the background. On the left, I paint the window mullions and other background details out of focus. 

In contrast to those empty shapes, I revel in the sharp accents and clutter of the worktable.

Studio host Garin Baker paints next to me. He'll be leading a painting workshop with Max Ginsburg and Christopher Pugliese this October in Bryn Mawr, Pennsylvania. Here's the link for more info.

Fun times and great camaraderie! Top row: Amber and John; Sarah, Kev Ferrara; Garin Baker and Jeanette, Not shown, Janet, John Varriano, and Mary Mugele Sealfon.

Previously: Motivated Light

Daily servings of color, light, and Dinotopia on Instagram.

Chernyshevsky's Philosophy of Art

I've been reading about 19th century Russian painting, and several books on the topic have mentioned that the artists were influenced by an 1853 essay called "The Aesthetic Relations of Art to Reality" by Nicolas Chernyshevsky.

By all accounts this essay was a kind of manifesto for the Russian painters and was a particularly significant influence on its leaders, such as Ilya Repin, Ivan Shishkin and Kramskoy. It explains why realism flourished longer there than it did in Western Europe.

Ivan Shishkin, Mast Tree Grove, 1898

For example, compare this painting by Shishkin in Russia in 1898....

Paul Cezanne, The Bathers, 1898-1905

...to this one by Paul Cezanne in France at the same time. What was different about the aesthetic philosophy in Russia?

The central notion of Chernyshevsky's essay is that reality is greater than art. At best, art is an attempt to replicate or reproduce reality, and therefore art is on a plane lower than reality.

This is a very different idea from the aestheticism of J.M.W. Whistler and others who suggested that it is the business of art to improve on nature. Whistler said, "Nature is very rarely right, to such an extent, even that it might almost be said that Nature is usually wrong." 

Around the same time that Chernyshevsky's influential essay was published in Russia, related ideas were published in England and America. John Ruskin's Modern Painters and Asher B. Durand's Letters on Landscape Painting (1855) preached a version of Truth to Nature that had a great influence on the movements Pre-Raphaelitism and the Hudson River School in English speaking countries. The main difference with Chernyshevsky is that he seems to lack the moralizing tone of Durand and Ruskin.

Ilya Repin, Portrait of Aleksei Pisemsky. 1880

All these thinkers advocated that the artist should have a reverence for the concrete facts of reality and to allow as much as possible for the painting to be a clear window to that reality. Repin's portrait of Pisemsky is a good example, where the technique is subordinated to the force of personality, made manifest in concrete facts.

Ruskin, Durand, and Chernyshevsky all advocated that artists—students especially— paint as faithfully from nature as possible, but since absolute leaf-for-leaf imitation of external details is impossible, artists should re-create (Durand used the word "represent") on canvas the truth they have experienced, penetrating to the Platonic essence.

In Shishkin's case this meant painting scenes that seemed "found" or "photographic" to the untrained eye, but were in fact carefully constructed using his deep knowledge of natural effects.

It took him a lifetime to discard the conventional formulas of the picturesque in landscape, and to invent a way to interpret the reality of a forest interior in oil paint.

Many contemporary realists place a great value on the aesthetics of brushwork, paint texture, and composition, but Chernyshevsky would have regarded this preoccupation as a foolish distraction, like focusing on the scratches and skips on a phonograph record instead of listening to the music. Just as a phonograph record aspires to deliver the experience of a live concert, a painting aspires to the fullness and presence of reality. (The concert/phonograph analogy is my own, and of course the phonograph came after his time; Chernyshevsky actually uses the analogy of an original painting versus an engraved reproduction of it).

Here are some excerpts of Chernyshevsky:

• A reproduction must as far as possible preserve the essence of the thing reproduced; therefore, a work of art must contain as little of the abstract as possible.
• Art expresses an idea not through abstract concepts, but through a living, individual fact.
• The essential purpose of art is to reproduce what is of interest to man in real life. 
• Reality stands higher than dreams.

In order to grapple with these ideas, I imagined a conversation between myself and Chernyshevsky. Please note that Cherny's comments are my supposition of how he would answer.

Me: Can a camera or a high resolution motion picture achieve this result? 

Cherny: No. The excitement that the human being experiences in the presence of reality can only be evoked by an artist with an inquiring mind who can imaginatively see into the structure and essential features of the subject, and express what it is about that subject that makes it interesting.

Me: Is the imitation of reality what we're after?

Cherny: No, the mere copying of external features will only lead to boredom, both for the artist and the viewer. There's a big difference between mindless copying and insightful reproduction of nature.

Me: Aren't such insights highly subjective? Science in recent decades has shown that there is no such thing as objective reality. Our perception of the world around us is a construct of our perceptual systems. Therefore, shouldn't we paint the world in a personal style that matches our own subjective view of the world?

Cherny: You make too much of that. Painting in the way you suggest is just an excuse for laziness. Two careful artists with good training will produce studies that match each other very closely. But such studies are just the beginning. It takes a lifetime to create works that address the deep experiences of life. 

Me: What about the Surrealist's goal of painting what is inside the mind, the world of dreams and nightmares?

Cherny: Your dreams ultimately come from reality. Imagination plays a key role, but the aim of the artist is to use the imagination to see into the heart of reality itself, which is the source of everything in its fullest and purest form. Reality is also full of latent mystery that cannot be fully understood by either the poetic avenue of art or the fact-based avenue of science.

Me: If reality is greater than art, of what value is a visit to the art museum?

Cherny: If it's a choice between the two, artists should look to reality for their chief inspiration; otherwise their work will become second-hand and mannered. But it is extremely valuable to study the means by which great artists of the past have expressed the essence of reality. Look for artwork that brings you closest to the feeling that you are in the presence of real life, and then try to understand how those effects are achieved. The challenge when you leave the art museum is to leave behind the conventions of past art movements, and to see reality for yourself without preconceptions.

Me: What categories of art are most worthy—sublime, comic, tragic, or beautiful?

Cherny: They are all important. A sensitive person will respond to the problems presented by life, and will want to create art that speaks to those problems, so that a fellow human can gain wisdom and insight from the art. Those impulses can run the gamut of emotions. Whatever way you respond to nature should be the subject of your art, but it should be conveyed in concrete, material terms.  

My concluding thoughts: I don't think Chernyshevsky's idea is completely tenable intellectually for me. I can't get past the idea that "reality" is a provisional thing, constructed in our own minds, and subject to the whims of our very selective and subjective visual systems. I also resist the notion that abstraction must always be avoided. Of course I love the Russian realists, but I also feel that a pulsing sense of life can emerge from certain highly abstracted forms of art, such as hand-drawn animation or comic art. 

But Cherny's idea that reality stands on a plane above art is for me an extremely useful driving concept that helps focus my mind when I'm out painting from nature. I often achieve my best results when I try to capture what's in front of me without trying to "improve" on it in any way. When I compare the immense complexity, subtlety, and richness of the real world to my own paltry efforts, I'm left with a sense of how far I have fallen short of the truth in front of me.
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"The Aesthetic Relations of Art to Reality" by Nicolas Chernyshevsky.
Nicolas Chernyshevsky on Wikipedia
Recommended book: The Russian Vision: The Art of Ilya Repin by David Jackson

Train Crossing

"Train Crossing," gouache, 5 x 8 inches

I went over by the railroad tracks while our car was in the repair shop yesterday.

A freight train rumbled past, smelling of lumber and oil and new cars. It shrieked its horn a lot because this is a deadly crossing. 

I always shudder when a freight passes because my only uncle was killed in an accident at a train crossing when he was a teenager. My mom didn't like it when I left art school to ride the freight trains across America, and I was unaware of the worry I must have caused her. 

But it was thrilling and wild to travel that way. We would throw our backpacks onto an empty railcar as it left the yard and it would blast us into the night through unknown cities in the pitch blackness and hurricane wind. We never knew what part of the country we would wake up in.

Painting is like that, full of unknowns and deep longings, but it takes place inside a contained universe. 

I used three colors of gouache: Perylene Maroon (which sounds like the name of a pirate), Viridian, and Yellow Ochre, plus White. The underdrawing is just a framework of measurements.

Here's what the painting looked like after an hour or so.   

Because every element in the scene was unloved and probably never painted by an artist before, I felt an even greater accountability to capture it as faithfully as I could.

I like gouache for a subject like this because it lets me paint the most delicate forms, such as the fine electrical wires and the far crossing gates in the distance, which were as small as slivers.

Video Review of 'Color and Light'

Jason Morgan just produced this video review of Color and Light: A Guide for the Realist Painter. (Link to YouTube) The book is available on Amazon.

Thanks, Jason. Check out Jason's website on his excellent wildlife art, photos, and videos.