Research Points: Optical Mixing and Effects



Georges Seurat ( 1859-1891)

Seated Boy with Straw Hat Georges Seurat

Seated Boy with Straw Hat
Georges Seurat


Seurat spent two years dedicated to developing his skill of black and white drawing around 1880-1882. He concentrated on tone and light in these drawings and often omitted lines to delineate areas, instead using marks built up to show dark against light.  This is particularly prevalent in “The Black Bow” or “The Black Knot” (1882), in conte crayon on paper, see link below:

Maybe these were his embryonic thoughts to using such mark marking with colour and tone in his subsequent paintings? In Seurat’s first large-scale painting, “Bathers at Asnieres” (1884) – National Gallery, he did not use Pointillism but similar mark making techniques to the drawings are apparent.  Even here, Seurat has not used broad sweeps of colour but smaller marks.  This painting depicts a bright summer’s day, the colours used are light and fresh, the shadows although cooler, are not cold but convey a subtle shade.  the darkest colours, eg the boots, trousers and hat are a rich deep brown, they still show the bright light of the sun.

Women by the Water 1885-6 Georges Seurat

Women by the Water 1885-6
Georges Seurat

In “Women by the Water” (1885-6) Oil on Wood 15.7x25cm shows Seurat using Pointillism with broken dots and dashes of colour but still following tonality and light. The colours are more intricate because of this,  compared to the “Bathers at Asnieres”, where colour appears simplified.  There are nuances of colour both in the light and dark tones, if not generally. This painting is best viewed at a short distance away,  the eye then “joins the dots” and gives, what looks disjointed close up, a recognisable image.


“A Sunday Afternoon on the Island of La Grande Jette” 1884 – there are many reproductions of this painting and many I have seen seem to be made of many coloured dots (ie Pointillism), in their entirety, however, looking at the Metropolitan Museum of Art website, I notice the multitude of short dash like marks over the majority of the painting. The grassy shadows have dashes of blue/green/orange//yellow which give the ground movement. There is similar treatment in the trees which really evokes the dappled sunlight and gently summer breeze.  It transpires that Seurat added the dots towards the completion of the painting, along with a dotted border. This border follows the tones of the painting where it touches, being darker over the trees, down along the grass shadows and lightens towards the water where the sun hits.  By laying complimentary colours alongside each other, he gives crisp colours a lively movement, for example the blues in the grassy shadow against the orange of the daisies.  He as also used colours close on the spectrum to give a variation in tone and mix colours, there is a lot of red and blue which interpreted as a violet/plum colour in many of the clothes.

Paul Signac (1863-1935)

A contemporary of Georges Seurat, Signac was intrigued by Seurat’s working methods and went on to help in the development of Pointillism.  I have to admit that I am not overly familiar with Signac’s work – possibly because he was eclipsed by Seurat? Seurat’s life was cut very short and maybe the more celebrated because of that – I don’t know.

I have found some paintings of Signac’s that particularly appeal to me:

Capo Di Noli (1896)

A coastal view from a cliff path which sings with colour. Allegedly not the actual colours but the colours the scene evoked in the artist’s mind’s eye.  It’s again as with Seurat, tonally working yet has a clean-cut vibrancy that comes from not mixing colour on the palette but with the eye.  In the detail of the attached link, the complimentary colours are lifting each other above the bland and really give a sense of the hot Mediterranean sun.

Complat le Chateau, Le Pre (1886)

Complat le Chateau, Le Pre 1886 Paul Signac

Complat le Chateau, Le Pre 1886
Paul Signac


This meadow scene reduces my initial thoughts to dust! I was beginning to think that this method was best used to describe strong Mediterranean sunlight – however, although the sun is still strong here, it has a hazier, Northern European feel. the dominance of blues in varying shades and tones gives a unifying effect and although the  shadows are distinct, it still feels close to midday sun.  I almost need to shield my eyes from the glare.



Grand Canal, Venice (1905)

Grand Canal, Venice 1905 Paul Signac

Grand Canal, Venice 1905
Paul Signac


This is a beautiful painting that brings to mind the onset of dusk in Venice – something I have witnessed and is magical, the history, lapping of the water and soft glow as the city begins its night-time illumination of dark canals. This took me right back there. If this isn’t colour evoking mood, I don’t know what it. the last of the sun glancing off the Basilica makes it appear alight.



Both Seurat and Signac had a method, technique, process – call it what you will. They worked from sketches and colour studies and painstakingly experimented with the juxtaposition of colours to give the right look, feel and atmosphere to their paintings. However, this is a labour of love – it had to be, whether it’s the love of the process itself or the finished article, I’m not sure. It took at least one or two years for each final painting and all done in the studio – it is therefore, even more astounding that the finished works are so fresh, vibrant and compelling.


Ops Artists

Victor Vasarely 1906-1997

Op Art is a phrase coined by Time Magazine in 1964 in specific relation to Julian Stanczak’s exhibition

Zebra 1938 Victor Visarely

Zebra 1938
Victor Visarely

of abstract paintings that used optical illusions as their focus called Optical Paintings. Artists had previously been exploring this concept much before the phrase came about. One of these being Victor Vasarely. Vasarely’s famous Zebra 1938 is a motif he revisited in several guises over the years. Prior to the 1960s-70s, he seemed to work mostly in black and white and then created amazingly elaborate and precise abstract paintings using colour as well as shape for his creations.  Attached is a link to his website that has since been created, showing the timeline of Vasarely’s work and journey – he manages to convey a wildness together with a restraint and control.

For me, these are interesting shapes and colours and I found his planning and painting “maps” intriguing but devoid of any feeling, seemingly clinical. I enjoyed the spherical pattern and line bending of the Vega Period more than most as these were as organic as they got. I will park this and re-examine at some point when maybe my understanding of abstract/optical art improves – not in the diary yet thought.

Bridget Riley 1931-

London born Bridget Riley divides her time between Cornwall, London and Vaucluse in France. A name I know of yet not am not particularly familiar with her work.  Again, I hit against my abstract art brick wall. Having perused some of Riley’s works on-line, these are a few that I was taken with:

Cataract 3 1967

An interesting name! The colours and design seemed more unremarkable until I enlarged the image – it completely came alive and made me compare it to a flag waving in the wind – albeit in a uniform way. The colour-ways help with this –  moving from black/blue & white to red/blue/white and back again.

Shadow Play 1990

Looking at this, I was a little lost, then I began to see it changing before me in planes and angles. I again enlarged it on my lap top and being a plasma-type screen, the imprints of circles from my fingers seemed to add even more to it.

Movement in Squares 1961

I have seen this before and is more obviously an optical illusion. I notice that it is made with Tempera on board, which seems an unusual choice – it would be good to understand these choices with such a concept.

Blaze Study 1962

As soon as I stray into realms of zigzags I feel uncomfortable, in fact this Optical Art is a bit of a struggle for me to really look at – particularly on a computer screen.  I think I should try to find examples to see in the flesh and see if they have the same effect.  The reason being, I am an occasional migraine sufferer and just by chance, have had a few attacks this week prior to this research.  This leads me to think that there is more than a visual effect from these works and more of a neurological impact – is this general or just me and fellow migraine-ees?? I’m all for emotional responses to works of art, I think this may just be a step too far for me.  I will seek out some exhibits just in case it is the combination of Op Art and computer screen.


Exercise: Complimentary Colours


Complimentary Colours

Complimentary colours are at opposite sides of the colour spectrum. One way to learn about locating and mixing these colours is to make your own colour wheel.

Colour wheel exploring complimentary colours Attempt 1 Acrylic

Colour wheel exploring complimentary colours
Attempt 1


Colour wheel exploring complimentary colours Attempt 2 Acrylic

Colour wheel exploring complimentary colours
Attempt 2

Next, consider the twelve colours from Chevreul’s colour circle and lay each colour next to its opposite or complimentary on a grey ground.  Try to match the darker tone to the lighter by adding white.


Make mixtures of each pair of complimentary colours. Make a note of the colours mixed and describe the resulting colour. this is another way of creating broken or tertiary colours.


Look closely at the effect that complimentary colours have on each other and try to explain this in your notes.

Comparing and mixing complimentary colours on a neutral grey ground. Acrylic.

Comparing and mixing complimentary colours on a neutral grey ground.

NB Observations are noted next to examples.


Research Point: Colour Theories of Chevreul and How Artists Have Applied Them

13 & 14/04/15

Michel Eugene Chevreul (1786 – 1889)

Find out more about the colour theories of Chevreul and make notes on how particular artists have used Chevreul’s theories to expand the possibilities of painting.

French Chemist of extensive scientific achievements, of which I’ll concentrate on his theories of colour. As Director of the Gobelins Manufactory in Paris – a dye works, he received complaints regarding the colour matching of the dyes produced for tapestries.  Particularly of blacks which appeared different when next to blues for example.  Chevreul discovered that perceived colour, when next to others, changed according to the adjacent colour, he called this the Concept of Simultaneous Contrast.

After much investigating and experimenting and giving extensive lectures in the subject, he wrote the book The Principles of Harmony and Contrast of Colours (published in English in 1854).

Chevreul’s findings influenced many things not least European art namely, Impressionism, Neo-Impressionism and Orphism or Orphic Cubism.

Whilst researching M. Chevreul’s theories, I came across a paper written by Georges Roque 2010, called Chevreul’s Colour Theory and its Consequences for Artists – Published by the Colour Group (Great Britain) 2011.

I have included a link to this paper, as it is, although lengthy, concise and above all interesting and readable.

Some points I found particularly fascinating:

  • The eye deceives the brain (or is it the other way around) when viewing tones adjacent to each other.
    (See anecdote regarding a court case between a wallpaper manufacturer and wealthy client – one disagreeing with the other as to the reproduction of a grey in the design, one saying it is absolutely the correct grey, the other saying it had a reddish tint. Chevreul brought as expert witness deduced both were correct, in isolation, the grey was accurate, yet against the background colour (green), it did indeed have a reddish tint).
  • I tried the experiment mentioned regarding a red dot on white paper, in that when viewed for a period of time, a pale green (blueish green in my case) glow appeared around the red dot, and when one looks away from the red dot, a greenish dot is seen against the white of the paper. Being a tad pedantic, I also tried this with a green dot and lo and behold a pale pink (we can say pale red if you like) glow appeared around the green! Blue – Gave pale orange! Okay, I believe him that this is the origin of complimentary colours. It appears to be a natural phenomena that occurs due to how our eyes work!
  • Colour mixing can be with coloured light or coloured pigment.
    Colour mixing with light is additive and more pure, and when equal intensities of colour are mixed it produces white.
    Colour mixing with pigment is subtractive and less pure, and when equal intensities of colour are mixed it produces black.

How Particular Artists have Used Chevreul’s Theories to Expand the Possibilities of Painting

Again. Georges Roque’s paper is very useful and informative, it is the fundamental reason for his writing it.  Without being too lazy, I have used the artists mentioned and researched them in this regard.

Eugene Delacroix (1798 – 1863)

Almost 10 years ago I had the opportunity to spend the entire day, unaccompanied by a bored spouse, in the Louvre, Paris. My most memorable part of this mammoth painting viewing extravaganza, was the wonderful paintings of Delacroix.  They were strong in colour, brushwork, story and passion and often of shocking subjects, yet they were still easy to view. How did he do this? It seems from Georges Roque’s research, that Delacroix was very interested in Chevreul’s theories and lectures. He made a triangular diagram in a sketchbook illustrating the relationships of complimentary colours which he used to bring harmony to his paintings.  He was also adept at bringing mood and meaning to his images by his use of colour.  One of my favourite paintings from that day was The Death of Sardanapalus, this seems to have been painted prior to Chevreul’s lectures on colour harmony, however, shows his natural affinity with colour and maybe why he became so interested in Chevreul in later years.  Learning the reason why something works so well helps recreate desired results.

Camille Pissarro (1830 -1903)

The only artist spanning both Impressionist and Neo-Impressionist movements. Chevreul’s theories are often related to these styles of painting as they shared a desire to recreate the colour and luminosity of light in nature.  Pissarro, as did other Impressionists, used complimentary colours to give life and light to his paintings, using local colour in shadows to bring a cohesive and harmonious appearance. Keen to expand knowledge and push theories, Pissarro became close to Georges Seurat and Paul Signac and explored the practice of pointillism. Examples of the use of complimentary colours to bring vibrancy and harmony being Old Chelsea Bridge London 1871 (Smith College Museum of Arts), *Toit Rouges, Coin d’un Village, Hiver, Cote de Sainte-Denis, Pontoise 1877 (Musee d’Orsay, Paris), the Garden of Pontoise 1877 and Children on a Farm 1887.

*Translation: Red Roofs, Corner of a Village, Winter, Cote de Sainte-Denis, Pontoise.

Georges Seurat (1859 – 1891)

Credited with the creation of Chromoluminanism or Divisionism: Maximum luminosity, separation of colours, dots or marks that interact visually;
Pointillism: Dots of paint not necessarily with separation of colours.

Interestingly, Seurat also studied Delacroix’s use of colour. He believed that harmony and emotion can be evoked with colour – refer again to Delacroix. Seurat took the science available to him vie Chevreul, Charles Blanc (a French art critic, who took Chevreul’s theories and applied then specifically to art) and Ogden Rood (again looking at colour theory and its application in art, was an American physicist). Referring back to Georges Roque’s paper, he notes that art historian Robert L Herbert discounts the claim of optical mixing and it has had some negative criticism in more recent times, however, even if the eye doesn’t exactly mix the colours, Divisionism and Pointillism does offer a high degree of luminosity in paintings.

Vincent Van Gogh (1853 – 1890)

As the paper of Chevreul by Georges Roque specifically comments on Van Gogh’s colour techniques (using quotes from his letters to brother Theo re Bedroom in Arles 1888), I will not repeat his conclusions, but refer to how this brilliant man with a delicate mind used his colours to again describe mood and emotion. He seemed to feel everything deeply and his adoption of some of the techniques used by Seurat and Paul Signac with dots of colour, helped him put these emotions into his paintings.  It seems to me this was a natural progression for Van Gogh as he was a master of mark making in his bamboo pen and ink drawings that he should find a way to combine this with complimentary colour juxtaposition. He seemed particularly taken with yellow/orange with blue. See:

The Cafe Terrace 1888
Van Gogh’s Chair 1888
The Starry Night 1889
The Sower 1888
and on and on…

Paul Klee (1879 – 1940)

An artist I am not overly familiar with and worth my revisiting at a later date. As noted in my course notes he was an artist and a teacher within the Bauhaus movement. I haven’t yet found much information relating to his colour theories, however, I noted a similar vein of thought to that of Georges Seurat. Both refer to the emotion, expression, rhythm in colour and structure of drawing and painting in a similar way that a musician uses counterpoint in composing harmony in music.

I have finally found a paper written by Roy Osbourne called Colour School (Thoughts on the Teaching of Colour Theory)

This refers to Paul Klee, Johannes Itten (1888 – 1967) and Joseph Albers (1888 – 1976).

In this link, Paul Klee refers to transparent colour mixing with watercolour – as crossed my mind when reading about colour mixing with light – does this refer to transparent colour? Although when mixed together, blue, red and yellow watercolour does mix to white but can some of the theory be applied – it certainly doesn’t mix to black???  No it refers to light and watercolour is pigment however transparent, I can see how confusion was caused – my head is spinning. Am now looking forward to the colour mixing exercises to answer and more than likely pose more questions.

Research via Wikipedia and Hints, Tips & Techniques, Colour Mixing Published by Winsor & Newton ColArt Fine Art & Graphics Ltd 1997. (Specifically The Terminology of Colour Theory)