Plenary lectures


Robert Hirschler
Hungary

color consultant, chair of the AIC Study Group on Color Education, founder of the SENAI/CETIQT Applied Colorimetry Lab in Brazil

Colour theory and neo-impressionist landscapes

Neo-Impressionism, pointillism and divisionism are terms often used interchangeably, but they have completely different meanings. Neo-Impressionism is an art movement which appeared in 1886 and was popular first among French, but soon thereafter also among other, mainly, Belgian, Dutch and Italian painters. Pointillism is the technique of placing small dots of paint close to each other on the canvas, wanting to create (but, as we shall see, not necessarily succeeding in) the optical mixing of different colours. Divisionism is the technique of placing dots, dashes or patches of different (often complementary) colours next to each other, and it may or may not use pointillism as the basic technique.

The theoretical foundation of neo-impressionist painters goes back to the works of Chevreul and Ogden Rood, both well known and, according to contemporary sources, well studied by Seurat, Signac & Co. The scientific novelty in end of 19th century France was the application of complementary colours next to each other, which – at least according to Seurat’s views – should have given a more luminous aspect to these paintings. The somewhat erroneous expectation that the “additive mixing” of tiny dots of primary colours (and here they already knew that in this situation those were red, green and blue) would result in white, or at least in brighter colours than the primaries themselves, caused disappointment.

In this paper we shall discuss the difference between additive mixing of lights (as happens in projecting overlapping lights of different colours or in spatial fusion of RGB dots on a monitor) and partitive (averaging) mixing of the reflectance of tiny paint dots (as in a pointillist painting) or that of differently coloured sections of a spinning disk. We shall see the reason for the fascinating impression created by these neo-impressionist painting being the result of the simultaneous contrast effect of neighbouring colours when watched from close and the optical mixing of the same when watched from a distance. According to recent research the dichotomy is also caused by the characteristic of human vision: the colour resolution of the human eye is much lower than the form resolution, and the unique scintillation of these painting seen at a certain distance is the result of our eyes already mixing colours but still distinguishing forms (those of the dots or dashes). The pointillist/divisionist technique lends itself particularly well to landscape painting as a genre, and in its variegated forms including townscapes and seascapes, sometimes populated, sometimes not, it was by far the most popular among neo-impressionist painters. It is telling that at the first modern exhibition of Neo-Impressionism (Guggenheim Museum, 1968) out of a total of 175 paintings there were only six still lives and fifteen figure paintings shown, the vast majority were landscapes, views of country and city. We shall have a close look at the colour science applied to some of the landscapes of the neo-impressionist masters, with special reference to Matisse’s majestic pastoral landscape Luxe, calme et volupté.


Verena M. Schindler
Switzerland

art and architectural historian, chair of the AIC Study Group on Environmental Color Design, former work at Atelier Cler in Paris

Jean-Philippe Lenclos’ methodology of the Geography of colour:
Back to the origins and its international impact

In the Proceedings of the International Colour Association Conference 2018, nine papers referred to Jean-Philippe Lenclos’ methodology for analyzing and synthesizing colours in the urban environment, a concept that he called the “Geography of Colour”. The authors of these papers are coming not only from European countries, but also from Latin America and Australia. This fact tells us much about the international impact that the “Geography of Colour” has still today: United Kingdom (Mikellides), Portugal (Diz de Almeida and Caramelo Gomes), Poland (Kwiatkowska-Lubańskaa and Tarajko-Kowalska), France (Xavière), Finland (Pyykkö), Turkey (Küçükkılıç Özcan and Ünever), Peru (Arrarte-Grau), Brazil (Brasil and Guerreiro), and Australia (di Cara).

The aim of this paper is to go back to the sources and thoroughly study Jean-Philippe Lenclos’ “Geography of Colour” as a concept that he developed in the 1960s. Important is also how the idea came into being. “While drawing in the tiny streets of Gion Machi and in gardens and temples, Ryoan-ji, Daizen-in, Ginkaku-ji, Koke-dera…, I was seeing space anew. In the silence, I learned the whole extent of matter and the beauty of rhythms. And the precious shadows of Tanizaki helped me, by pure contrast, to mesure the primacy of the light that gave life to every color. Then the idea came to me, as proof, that Japan’s specific colors took part in its cultural identity. This revelation was born of the comparison with my own country of origin, the Pas-de-Calais, in the north of France where Matisse was born–a humid land where the habitat pays tribute to the bright tones of its orange tiles and brick-red façades, constrasting in a Fauvist manner with the intense green of the vegetation.” (Jean-Philippe Lenclos, 1999).

Lenclos applied “The Geography of Colour” to a country, town, or village. He began with the systematic inventory of local colours and architectural traditions in various regions of France. Considering regional colours as belonging to the history, geography, and cultural identity of a place, the concept was extended beyond his native France to other European countries and beyond to other continents. These efforts resulted in a distinguished body of publications including: Colours in France (1982), Colours in Europe (1995), Colours of the World (1999), Doors of the World (2001), Windows of the World (2001), Houses of the World (2007), and Colours of the Mediterranean (2016). Some of the books co-authored with his wife Dominique Lenclos have been translated into English, Japanese, and Korean. Furthermore, this paper analyzes the ways in which his ideas were applied in the nine papers mentioned above.


Ming Ronnier Luo
United Kingdom

professor of Zhejiang University (China), National Taiwan University and Leeds University (UK), AIC Judd awardee 2017

A summary of the parametric studies on colour difference evaluation

Colour difference research has been extensively investigated over the years. CIEDE2000 was proposed in year 2001 and has been tested from various new data. However, these formulae can only be applied under a set of  reference viewing conditions as defined by CIE, i.e. a pair of samples should be object colours, large sample size with edge contact, small to medium magnitudes, and be observed under a D65 simulator, and should be observed under high luminance level, against a mid-grey background. In reality, this set of reference conditions is difficult to achieve. Various studies have been carried out to study the impact of different viewing parameters with intention to develop a parametric colour difference equation to consider different viewing conditions.

This paper will review the research works conducted to study different viewing parameters including mode (aperture vs surface), assessment method (perceptibility vs acceptability), materials (textile, coating), media (surface vs display), contents (patches vs images), physical size, separation, colour difference magnitude, background colour, illuminant.

For each parameter, the visual phenomena will be shown and the colour difference equation will be proposed to model the effect. Finally, conclusion will be drawn on what important parameters had a significant impact on colour difference evaluation and a generic equation will be proposed to consider these parameters.


AIC Color in Art and Design award lecture

Roy Osborne
United Kingdom

artist, author and educator, former chairman and Turner Medal awardee of the Colour Group of Great Britain

Renaissance colour symbolism

Between 1495 and 1595, a unique series of texts were published in Paris and Northern Italy on the subject of colour symbolism. The first was written by the Sicily Herald (Jehan Courtoys) about 1420, and the last by Antonio Calli. They all relate to the choice of colour in dress, and extend and promote ancient and medieval beliefs that colour was a divine manifestation that could possess profound meaning and supernatural power. Roy Osborne’s talk will summarise the content of these publications, the two most influential of which were Gilles Corrozet’s Le Blason des couleurs en armes, livrées et devises (Paris, 1527), translated into Italian in 1565, and Fulvio Pellegrino Morato’s Del significato de’ colori (Venice, 1535).

After the appearance of Andrea Alciato’s ‘Emblem book’ (Augsburg, 1531) and Clément Marot’s ‘anatomical blazons’ (Lyons, 1536), there was a mid-century craze for moralistic poetry, out of which came Morato’s colour sonnet, offering meanings for a series of 14 colours extracted from some 60 ancient and medieval sources, principally Virgil, Horace, Ovid, Pliny the Elder and Petrarch.

Corrozet’s sources are more obscure, and the ‘second tract’ of his book on blazons appears to offer the most extensive record of contemporary European colour symbolism. Together, the two authors were influential particularly on subsequent colour publications by Coronato Occolti (Parma, 1568), Giovanni de’ Rinaldi (Ferrara, 1584) and Giovanni Paolo Lomazzo (Milan, 1584).

Remarkably, after Calli’s Discorso de’ colori (Padua, 1595), no original books wholly on colour symbolism were published for almost 250 years, until Frédéric de Portal’s Des Couleurs symboliques, dans l’antiquité, le moyen âge, et les temps modernes (Paris, 1837). This would seem to suggest that, after about 1600, previous, subjective notions about the magical powers of colour were largely discarded during the Baroque era, most probably owing to the rise of empirical science, and a novel belief that light and colour were physical phenomena to be examined objectively, with optical instruments and mathematical calculations.

Though Goethe revived an interest in colour associations in his Farbenlehre (Tübingen, 1810), it is not until the rise of literary and artistic Symbolist movements in Europe, and such Theosophical publications as Annie Besant’s Thought-Forms (London, 1901), that the practice of attributing specific meanings to colours is again popularly embraced. Thereafter, and throughout the twentieth century, considerations of the indicative meanings of colours were integrated into the visual arts and various aspects of colour psychology and therapy.


AIC Deane B. Judd award lecture

Hirohisa Yaguchi
Japan

professor emeritus of Chiba University, CIE awardee 2009, past-president of CIE-Japan, organizer of AIC 1997 and AIC 2015

Individual color vision

The most widely used CIE color system is based on a single observer, called the CIE 1931 standard colorimetric observer. However, color vision is more or less different in individuals. Such an individual difference sometimes becomes a problem to make a quantitative model. Therefore, a set of visual functions from a single observer is useful to make a color vision model. I have employed myself as a subject and measured various visual functions with psychophysical methods. These are the color matching functions, the spectral luminous efficiency functions by heterochromatic flicker photometry, and the opponent-color response functions by hue cancellation method. From the analysis of the relation among various visual functions obtained from a single observer, it is suggested that the L-cone and the M-cone signals are linearly transformed to the achromatic channel, the r/g opponent color channel is linearly processed by the transformation of cone signals, and the y/b opponent color channel is non-linearly processed by the cone signals of the L-cones and S-cones.

As for individual differences in color vision, color vision deficiencies and aging effects could be considered to be the major factors. In 2006, CIE defined the cone fundamentals as the relative spectral sensitivity of cone receptors as measured in the corneal plane. We have developed a color appearance model for anomalous trichromats using the CIE 2006 cone fundamentals. Even if the colorimetric values of two stimuli with different spectral powers such as an object color and a display color are equal, different colors may be seen. It is considered to be a problem of observer metamerism, which is caused by the fact that the color matching function of a real observer is different from that of a standard colorimetric observer. It was suggested that the problem of observer metamerism could be analyzed with a color appearance model for anomalous trichromats and also aging effects.

Thanks for the long-standing research and activities in CIE and AIC, the cone fundamentals for a standard observer and further the CIE2015 XYZ colorimetric system based on the standard cone fundamentals have been established. In the near future, it would be desirable to establish a colorimetric system for individual color vision.