Research point: Optical effects

Updated on 28 February 2017 (Harvard referencing).

16/18 May 2016. Hard question – what is an optical effect? I had a look on the internet and what came closest to a fundamental definition was “optical phenomenon”. I guess that in the context of this post I will need to address the subject as optical phenomena used to create particular optical effects.
While optical phenomena are good to describe physical and/or chemical realities (for want of other accessible summaries see Wikipedia (2012)), I have to admit that it took me a while to come to terms with “effect”. What effects would I (want to) see on a canvas?

• the illusion of three dimensions on a two-dimensional support
• the illusion of illumination without the actual presence of a source of light
• the illusion of movement in a static image
• creation of vertigo or being drawn into a painting
• optical illusions
• … and no doubt many more which I am not aware of at the moment,

so probably and basically, any interaction between colours and linear elements defined by the sum of all their characteristics (shape, size, relative position, hue, tone, tint/shade, brightness, etc. (WorkWithColour.com, n.d.)) that is not a simple perception of the presence of an element alone.

Optical phenomena need, most of the time, the presence of a minimum of light to fall on the retina. There are, however, effects, which work without light, which are visible with closed eyes or in absolute darkness and which are created by the human mind. Migraine and epilepsy are two conditions, which can evoke visual auras, both unconnected to sensory input from the outside world. Also, daydreaming and mental images might be considered important sources of “visual” information, which can be used in painting.

Even the earliest painters will have observed and put to good use optical effects available to them. A scientific approach, however, with whole artists’ lives dedicated to the exploration of colour and publication of results often as series of painstaking images (see e.g. Josef Albers and his series “Homage to the Square” (Lacher-Bryk, 2016a), started only with an increase in reliable knowledge of colour physics and physiology. Referring to the introductory text of the study guide (Open College of the Arts, 2011, p. 67) I am expected to specifically refer to the use of optical effects by the Impressionists and their immediate successors, in particular the Pointillists. Since I already wrote an extensive blog post on this subject (Lacher-Bryk, 2016b) and found out that the “achievement of optical mixing” is in fact inexistent due to the low resolution used, I decided that I would take the risk and deviate somewhat from the instructions to see what other optical effects I could find, not limiting my search to the effects of colour alone.
I remember a fascinating drawing or woodcut from a pocket calendar I owned as a child, which consisted of a set of seemingly meaningless bands of varying width when looked at in the usual manner, but which revealed its secret when viewed from a very low position, nearly head on. It was an example of extreme foreshortening called anamorphosis (Kent, 2013). I did not find the particular image on the internet, but came across a great number of fine paintings from historical times and the present day. Among these, the skull on Holbein the Younger’s (c. 1497-1543) “Ambassadors” from 1533 (Fig. 1) is a very famous example. Watch an interesting video discussion by Harris and Zucker (2012).

Figure 1. Hans Holbein the Younger: “The Ambassadors”, 1533, oil on canvas. Source: Hans Holbein the Younger (c. 1497-1543) [Public domain] via Wikimedia Commons

Having started looking through the subjects on offer by Khan Academy I also came across an introductory article to contemporary art (Spivey, n.d.). The second image shown there, John Baldessari’s lithgraph “I Will Not Make Any More Boring Art” created in 1971, apart from its great message reminding me of Bart Simpson’s writing on the blackboard, is for me a wonderful way of creating vibration by repeating similar structures, in this case the elements of handwriting. The “k” in “make”, for example seems particularly alive across the whole canvas and beyond, in a Rumpelstilzkin manner fitting the rebellious statement.

Julie Mehretu’s 2003 “Empirical Construction” is a good example for a set of optical effects combined to create the illusion of fast movement. Linear elements placed in parallel perspective produce the illusion of a three dimensional space and also force the viewer’s gaze away from the centre by becoming thicker the further away from the centre. At the same time, curved lines surrounding the objects suggest a turning and tangential movement. Both types of elements create them impression of the witnessing of an act of explosive disintegration of variously coloured geometrical elements, which may have been part of a magnificent edifice just a second ago. When looking at the details of the ca. 3 x 4.5 m canvas, they repeat the effects at smaller scale, so that every bit of the construction seems to be in concerted movement, the sum of which produces an explosive whole. In an interview (Caruth, 2013) Mehretu also explains that the layering of a multitude of elements forces the eye to constantly adjust, so that a further illusion of movement is created, this time not only in  space, but also in time.

Op Art, or “optical art” is defined as an art form specialising in the use of optical illusions (Tate, n.d.(a)). It evolved predominantly from the first avant-garde movement of Neo-Impressionism, (Tate, n.d.(b)) which already included the word “optical” in its definition and “promised to employ optical and psycho-biological theories in pursuit of a grand synthesis of the ideal and the real, the fugitive and the essential, science and temperament.” Paul Signac’s (1863-1935) Neo-Impressionist painting below (Fig. 2) is a good example of the above. It illustrates also the point of non-achievement of optical mixing at normal viewing distance. It works only if the image size is reduced to, say, no more than 5 x 5 cm. Since this option was of course unavailable to contemporary viewers, they would no doubt have had to move very far from a well-lit canvas to see the desired effect.

Figure 2. Paul Signac: “Portrait of Félix Fénélon”, 1890, oil on canvas. Source: Paul Signac (1863-1935) [Public domain] via Wikimedia Commons

The dots and blocks of colour introduced by the Neo-Impressionists to transport a notion of organisation were taken up and developed further by following art movements until they evolved as separate art forms. Op Art painter Bridget Riley (*1931, UK) is famous for her life-long influential investigation of the interaction of form and colour (Riggs, 1998). Her one-of-a-series oil painting “Winter Palace” (1981), as shown on p. 67 of the study guide (Open College of the Arts, 2011) and e.g. by the National Gallery (n.d.) was influenced by the colours seen in Egyptian tombs. In a description provided by Artfund (n.d.) the effect is described as follows: “Just as in her earlier optical pictures, a vibrant surface is created with vertical bands causing the eye constantly to refocus, moving forward and back in space as one colour then another asserts a pull.”, which is a good description of the created effect and an example of the “disorientating optical effects of geometric forms”. In me, when looking at it for more than a few seconds, it will cause an intense feeling of dizziness, probably due to the mix of phenomena at work at the same time. For easier reference I take the neutral grey lines as uniform background on which the coloured lines operate, e.g. and without doubt missing several more:

1. Each line, when seen on its own, appears to lie on one plane with the neutral background.
2. Between each two lines separated by grey there appears the illusion of a narrow darker grey line.
3. Each line appears to rest, at the same time, both on and above the picture plane, depending on the combination of colours seen together, e.g. in both combinations white and pink as well as pink and black the pink appears to lie above the other colour, but only if not separated by grey.
4. A black line pulls the eye beneath the picture plane strongly in combination with pink, appears to lie above the plane next to yellow and appears unchanged between two turquoise lines.
5. The most intense “wave” illusion is formed in the sequence “ochre-turquoise-black-turquoise-ochre-grey-white-pink-turquoise-black-grey-ochre”. To my eye, the sequence containing ochre, turquoise and black appear to lie more or less on the same plane, while the white and pink followed by the turquiose and black stripes appear to lie above it.
6. When shifting my viewpoint to the left or right to include other combination of lines, the effect is diminished.
7. There is a huge difference if I look at the painting with one instead of both eyes. In my opinion the effect is more dramatic with one eye closed, probably because compensatory information from the other eye is missing.

In fact, I could go on forever. The more I look, the more effects I discover and there is not a single painting or drawing without any. To me, even Kasimir Malevich’s famous “Black Square” (Shaw, 2013) produced in 1915, sort of flutters both inside and at its edges in the most uncomfortable manner, as if it were trying to move into the white area surrounding it. In fact, a wonderful remark made by Malevich, reinforces my impression: “It is from zero, in zero, that the true movement of being begins.” (Smith, 2003)
Big Bang. Better stop here.

Resources:

Artfund (n.d.) Winter Palance by Bridget Riley [online]. Artfund, London. Available at: https://www.artfund.org/supporting-museums/art-weve-helped-buy/artwork/6966/winter-palace-bridget-riley [Accessed 28 February 2017]

Caruth, N.J. (2013) Julie Mehretu: To Be Felt as Much as Read [interview] [online]. Art 21. Available at: http://www.art21.org/texts/julie-mehretu/interview-julie-mehretu-to-be-felt-as-much-as-read [Accessed 16 May 2016]

Harris, B. and Zucker, S. (2012) Holbein the Younger, The Ambassadors [online]. Khan Academy. Available at:  https://www.khanacademy.org/humanities/renaissance-reformation/northern/holbein/v/hans-holbein-the-younger-the-ambassadors-1533 [Accessed 16 May 2016]

Kent, P. (2013) Art of Anamorphosis [online]. Philpp Kent, London. Available at: https://www.anamorphosis.com/ [Accessed 27 February 2017]

Lacher-Bryk, A. (2016a) Artist research: Edward Burra, James Rosenquist and Josef Albers [blog] [online]. Andrea’s OCA Painting 1 blog. Available at: https://andreabrykocapainting1.wordpress.com/2016/05/02/artist-research-edward-burra-james-rosenquist-and-josef-albers/ [Accessed 16 May 2016]

Lacher-Bryk, A. (2016b) Research point: Chevreul’s Colour Theory [blog] [online]. Andrea’s OCA Painting 1 blog. Available at: https://andreabrykocapainting1.wordpress.com/2016/04/03/research-point-chevreuls-colour-theory/ [Accessed 16 May 2016]

Mehretu, J. (2003) Empirical Construction, Istanbul [ink and synthetic polymer paint on canvas] [online]. Museum of Modern Art, New York. Available at: https://www.moma.org/collection/works/91778?locale=en [Accessed 16 May 2016]

National Gallery (n.d.) Winter Palace [oil on linen] [online]. Leeds Art Gallery. Available at: https://www.nationalgallery.org.uk/initial-teacher-education/primary/learning/briley.aspx [Accessed 28 February 2017]

Open College of the Arts (2011) Painting 1. The Practice of Painting. The Bridgeman Art Library, London, New York, Paris, p. 67

Riggs, T. (1998) Bridget Riley: Biography [online]. Tate, London. Available at: http://www.tate.org.uk/art/artists/bridget-riley-1845 [Accessed 28 February 2017]

Shaw, P. (2013) Kasimir Malevich’s Black Square [online]. In Llewellyn, N. and Riding, C. (eds.) The Art of the Sublime, Tate Research Publication, January 2013. Available at: https://www.tate.org.uk/art/research-publications/the-sublime/philip-shaw-kasimir-malevichs-black-square-r1141459 [accessed 28 February 2017]

Signac, P. (1890) Portrait of Félix Fénélon [oil on canvas] [online]. Museum of Modern Art, New York. Available at:https://en.wikipedia.org/wiki/Paul_Signac#/media/File:Signac_-_Portrait_de_F%C3%A9lix_F%C3%A9n%C3%A9on.jpg %5BAccessed 16 May 2016]

Smith, R. (2003) Art Review; A Bombshell of Modernism Recaptured [online]. The New York Times, 13 May 2003). Available at: http://www.nytimes.com/2003/05/13/arts/art-review-a-bombshell-of-modernism-recaptured.html [Accessed 28 February 2017]

Spivey, V.B. (n.d.) Contemporary Art, an introduction [online]. Khan Academy. Available at: https://www.khanacademy.org/humanities/art-1010/beginners-guide-20-21/a/contemporary-art-an-introduction [Accessed 16 May 2016]

Tate (n.d.(a)) Op Art [online]. Tate, London. Available at: http://www.tate.org.uk/learn/online-resources/glossary/o/op-art [Accessed 27 February 2017]

Tate (n.d.(b)) Neo-Impressionism [online]. Tate, London. Available at: http://www.tate.org.uk/learn/online-resources/glossary/n/neo-impressionism [Accessed 27 February 2017]

Wikipedia (2012) Optical Phenomena [online]. Wikipedia. Available at: https://en.wikipedia.org/wiki/Optical_phenomena [Accessed 16 May 2016]

WorkWithColor.com (n.d.) Color Properties/Terminology [online]. WorkWithColour.com. Available at: http://www.workwithcolor.com/color-properties-definitions-0101.htm [Accessed 27 February 2017]

1. https://en.wikipedia.org/wiki/Black_Square_%28painting%29

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Research point: Chevreul’s colour theory

Updated on 19 February 2017 (Harvard referencing).

3 April 2016. Michel-Eugène Chevreul (1786-1889) was a multi-talented, ingenious chemist in 19th century France, who, after having been urged to investigate the reason for the apparent turning grey of high quality yarn used in the making of tapestries, devised a groundbreaking classification of colours, a chromatic circle (Fig. 1), to serve as first-ever standard for weavers and dyers. It was and still is being adapted and extended by many contributors (Costa, 2009).

Figure 1. Michel-Eugène Chevreul (1861) Chromatic circle. Source: Michel-Eugène Chevreul [Public domain] via Wikimedia Commons

The original trigger for his research had been one observation where the nature of blacks appeared to change when seen next to blues and violets in tapestries. After doing some research on that major problem Chevreul came to the ingenious conclusion that colours set next to each other mutually influence the perception of their respective nature. Chevreul described this main observation as the Law of Simultaneous Contrast of Colours, stating that “In the case where the eye sees at the same time two contiguous colours, they will appear as dissimilar as possible, both in their optical composition and in their strength of colour” (emphasis added by me). It was first published in an English language translation of his 1839 book, “The Principles of Harmony and Contrast of Colours and their Application to the Arts” (1855) (Roques, 2011, p. 4).
The above statement was interpreted by Chevreul as a tendency of the brain to enhance perception by exaggerating differences in lightness and hue, in particular along the common border (Roques, 2011, pp. 4-5, for the effect on lightness see top row in Fig. 2 below). The same works also for the bottom image in the same illustration. In the row of increasingly dark stripes the different borders to the left and right of each stripe will make them resemble “channelled grooves more than plane surfaces”. This effect is known as “Chevreul’s illusion”.

Figure 2: Redrawn detail from original by M.-E. Chevreul (1839) Illustration of the contrast of lightness. Source: Georges Roques after M.-E. Chevreul (1839) [Public domain] via Roques (2011)

When the law is applied to hue, the following effects are observed: Placing side by side narrow strips of different tones of the same colour or strips of the same tone in different colours influences both the perception of intensity (contrast of tone) and optical composition (contrast of colour) of each colour, hence the name “simultaneous contrast of colours” (Roques, 2011, p. 6).
The basis of the perceived modifications depend upon the concept of complementary colours first observed by Buffon in 1743 (e.g. after staring at a red dot  for some time, it will appear green when moving the eye to a white sheet, Roques, 2011, p. 7) and observations by Hassenfratz regarding coloured shadows created by the simultaneous use of two different light sources (Roques, 2011, p. 7). Chevreul considered, in line with his observation for lightness, that complementary colours are those which are the most opposed. Exaggerating differences in this context means that the brain will add to each of the juxtaposed colours a little of the colour complementary to each. A white pattern on coloured grounds will thus appear tinted with the colour complementary to that of the ground. Adding some of the background colour to the pattern influenced by the complementary colour will neutralize the effect. And, importantly, juxtaposing complementary colours has the effect of enhancing each other, since to each is added some of itself (Roques, 2011, pp. 8-9).While the basic physical mechanisms of colour perception are not disputed and Chevreul’s explanations are supported by findings in neuroscience, there exist several conflicting theories regarding the mutual influence of colours and their effect on the perception of colour in art (Roques, 2011, p. 9), while a main point of criticism is that according to modern standards Chevreul confused additive and subtractive mixing, the former referring to mixing light, the latter to pigments and which are incompatible (Roques, 2011, p. 10). It is also important to remember that the observed effects depend on the size (area) of the coloured samples. In cased the samples are very narrow, the colours will “fuse” to be perceived as an average between the two juxtaposed colours (Roques, 2011, p. 11).

Chevreul’s work, increasingly so as he moved from pure to applied science, was of immense interest for whoever used colour at the time. Since, however, many workers of the time became acquainted with Chevreul’s theories in a second-hand fashion there were some misunderstandings transported regarding their true nature and some artists adopted a style of painting based on misinterpretations (Roques, 2011, pp. 12-13). Interestingly it was mostly artisans, and not painters, who appreciated Chevreul’s findings when solving practical problems. Painters were only interested in the enhancing effect of juxtaposing complementary colours and tended to ignore the unwanted effects in other colour pairs. Among the painters interested in Chevreul’s findings was Eugène Delacroix (1798-1863, France) (Fig. 3). The example below is a good example of applying complementary colours, see especially the flags on the ground (Roques, 2011, p. 16):

Figure 3. Eugène Delacroix: “Entry of the Crusaders into Constantinople”, 1840, oil on canvas. Source: Eugène Delacroix (1798-1863) [Public Domain] via Wikimedia Commons

Despite contrasting opinions it is obvious that many painters deliberately applied their knowledge regarding the use complementary colours, e.g. Impressionist Claude Monet (1840-1926) or Impressionist and Neo-Impressionist Camille Pissarro (1830-1903) in the following painting, where the juxtaposed greens and reds assume a great brilliance. He even went as far as taking in Chevreul’s advice to pay attention to the effect the colour of the frame has on a painting.

Camille Pissarro: “The Red Roofs”, 1877, oil on canvas (source: Wikimedia Commons)

During Neo- and Post-Impressionism painters became increasingly interested in the organisation of colours on the canvas. Among these, Neo-Impressionist and theoretician Paul Signac (1863-1935) and Georges Seurat (1859-1891) were most avid in their application of Chevreul’s colour theory, especially when “optically mixing” by placing small dots of complementary colours next to each other. According to Roque (p. 18) there was another misunderstanding at the base of their idea: rather than enhancing the respective complementary colour, the effect would be one of averaging them out, since they did not take into account Chevreul’s warning of not confusing contrast and mixing, the presence of which depends on the size of the sample of colour. The luminosity remains in their paintings, because the dots are big enough for optical mixing NOT to work (Roque, p. 19).

Georges Seurat: “The Seine and la Grande Jatte – Springtime 1888″, oil on canvas (source: Wikimedia Commons)

Vincent van Gogh (1853-1890) was another painter with a keen interest in colour theory. Since he had a great liking for yellow, many of his paintings have juxtaposed a large proportion of the complementary colour, violet, e.g.:

Vincent van Gogh: The Café Terrace on the Place du Forum, Arles, at Night, 1888, oil on canvas

 

Roque, on p. 21, discusses also van Gogh’s description of the ideas behind the famous painting of his bedroom, on the base of which was an interest in transporting an impression of rest by the selective use of colour. To this end van Gogh used both the contrasts of complementary colours AND the same hues in different states.

Chevreul’s ideas continued to be of interest with the beginning of abstract art. Since the latter artists has a particular interest in the organisation of colour on the canvas, his theory helped them organise their ideas. Foremost among these was Robert Delaunay (1885-1941), who used it to systematically structure his abstract paintings. His intention was to capture colour vibration and transport it to the eye of the viewer by applying a phenomenon which Chevreul called “mixed contrast”: Seeing one colour, followed by the illusion of its complementary, superimposed on the colour of another object introduced at a later point in time.

Robert Delaunay: “Le Premier Disque”, 1912-1913, oil on canvas (source: Wikimedia Commons)

 

Despite an increasing tendency to challenge and replace Chevreul’s ideas with newer findings, they are still in use as a basis of teaching colour theory today (Roque, p. 24).

References:

Costa, A.B. (2009) Michel-Eugène Chevreul. French Chemist [online] Encyclopaedia Britannica. Available at: https://www.britannica.com/biography/Michel-Eugene-Chevreul [Accessed 3 April 2016]

Chevreul, M.-E. (1883) Chromatic Circle [n.a.] [online] Linda Hall Library, Kansas City. Available at: https://commons.wikimedia.org/wiki/File:Cercle_chromatique_Chevreul_3.jpg [Accessed 19 February 2017]

Delacroix, E. (1840) Entry of the Crusaders into Constantinople [oil on canvas] [online]. Louvre, Paris. Available at: https://en.wikipedia.org/wiki/Entry_of_the_Crusaders_in_Constantinople#/media/File:Eug%C3%A8ne_Ferdinand_Victor_Delacroix_012.jpg [Accessed 3 April 2016]

Roques, G. (2011) Chevreul’s Colour Theory and its Consequences for Artists, Colour Group, Great Britain. Available at: http://www.colour.org.uk/Chevreuls%20Law%20F1%20web%20good.pdf [Accessed 3 April 2016]