Colours in Arts

How many colours?

From my passion4science blog: Newton’s theory of colours  we learn that our eyes can differentiate some 10 MILLION different colors (hues).

Newton numbered SEVEN of them for reasons explained in my  passion4science blog.

Complementary colors: warm/ cool

Researchers from Ohio State University, Columbus noted that the perception and naming of color is remarkablyconsistent in the world’s languages. Across cultures, people tend to classify hundreds of different chromatic colors into EIGHT distinct categories: red, green, yellow or orange, blue, purple, brown, pink, and grue (green or blue) . Some languages classify colors into fewer categories, but even these are composites of those eight listed above. These researchers used data from the World Color Survey, a collection of color names supplied by 2,616 people of 110 mostly unwritten languages. The survey’s 320 different colors are organized into eight rows of 40 color chips per row. (Black, white, and grays are each in their own category.)

The researchers found a major distinction between warm and cool categories for many of those cultures that have just two or three common colors. That distinction tends to coincide with English colors that are thought to be warm (yellows, reds, and oranges) and cool (greens and blues). “While there is some diversity in the location of the color boundaries, there is an absolutely rock solid boundary across all the cultures, which English speakers would call warm and cool,” Lindsey states.

From Just how many colors are there? (USA Today (Society for the Advancement of Education)

This “universal” distinction between “warm” and “cool” colors is consistent with the notion of “complementary colors” in color theories. “Warm” and “cool” colors are “complementary colors”! (see above diagrams)

In color theory, two colors are called complementary if, when mixed in the proper proportion, they produce a neutral color (grey, white, or black). They “balance each other”.

Primary colors and secondary colors are paired in this way:




They can also be “categorized” as  “warm” and “cool”. This “warm” /”cool” relationship is well known by artists. Instinctively they know that they “support each other”, i.e. they are complementary (not “opposite” as in some “color theories”). An artist knows that a “warm” color reinforces a “co0l” color (and vice versa), creating a CONTRAST which a Van Gogh was fond of.

Here is an example by Van Gogh using the BLUE YELLOW contrast.

"Cafe Terrace at Night" by Vincent van Gogh. He is well known for using two complementary "secondary" colours; "blue" and "yellow" to maximize their mutual contrast.

Because of the limitations imposed by the range of colors that were available throughout most of the history of art, many artists still use a traditional set of complementary pairs, including:





Here is another example of van Gogh using this time a YELLOWISH GREEN with a BLUEISH MAGENTA (Purple/Violet) contrast.

Irises 1889 by Vincent van Gogh. Here he “mixes” green against purple (dark magenta)

And this shows the RED / GREEN complementarity (contrast):

Optical mixing

When two colours are right next to each other your eye mixes them in a process called, “optical mixing.” Using optical mixing rather than physical mixing can create a brighter picture, especially when using complementary colors.

When we use this technique, we are mixing colors — not by blending them together — but by placing two colors side by side. It’s called the optical mixing of colors. For instance, we may place clusters of red dots and surround them with yellow dots. Up close we will see red and yellow, but from a distance, we will see orange.

By separating paint into small dots of color, artists break their paints into their most basic elements. Up close, a Pointillist painting can look slightly confusing, but as the viewer backs away, the picture comes into focus. This is because the eyes and mind work together to blend the dots of color into a smooth picture, much like people interpret pixels on a computer screen as a single image. In fact, Pointillism is very similar to the CMYK printing process used to produce many printed materials; try magnifying a page in a magazine to see the individual dots of color which your eye has smoothed for you.

mixing of coloured light

Magenta Ain’t A Colour

We see everything in perspective thanks to the shape of our eyes.

Perspective, in art, is any technique employed to represent three-dimensional objects (as in space) on a two-dimensional surface the way our eyes naturally see them.

When you look anywhere, you could notice a progressive diminution of perceived objects: the farther, the smaller they look, they appear to us. This is the basic notion of “perspective”.


It took millenia to understand the science involved.

Très Riches Heures du Duc de Berry

Here is an example of a 15th Century French painting showing no sense/ understanding of perspective (from Les Très Riches Heures du Duc de Berry)

Masaccio, Holy Trinity, c. 1427

The invention of perspective is generally attributed to the Italian architect Brunelleschi, and the ideas continued to be developed and used by Renaissance artists (15th Century in Italy), notably Piero Della Francesca, Andrea Masaccio or Leonardo da Vinci. The first book to include a treatise on Perspective, ‘On Painting’ was published by Leon Battista Alberti in 1436.

Perspective’s two basic principles are:

  1. All parallel lines (i.e. of same direction) point towards one unique pointSince they are parallel, they will never “touch each other” (or “touch at the infinite”). This point is abstract, yet real.
  2. All objects recede in size towards these “point(s)”, ultimately receding to size “zero”, towards “vanishing points”.
As a consequence, any direction in our three-dimensional space points towards its unique “vanishing point”.
The following example shows a chair which has three directions (“vanishing points”)


In the following diagram, we can see three “vanishing points) in red, blue and black, all three corresponding to three distinct directions (or “parallel lines”).


When all these directions are parallel to the same flat surface (e.g. our ground), their respective vanishing points belong to a  same “vanishing line” we call “horizon“. In the above diagram, the horizon goes through “vanishing points” 1, 2 and 3 which is the “vanishing line” of the ground where the observer stands.

Likewise, any flat surface parallel to this ground will point towards the same “vanishing line” (horizon).

Vanishing line

Practical Perspective:

I do not expect you to know how to exactly construct a perspective (I know how to thanks to my university studies in Architecture and to teaching in this field). “Scientific perspective” is not necessary for artists.

In order to use perspective in an artistic project, all you need is to locate the key “vanishing points”.

Let’s have a look at this famous Disney character…

Perspective of the face

As you can see, Donald Duck’s face is drawn here in perspective: his left-hand side recedes, is shorter than his right-hand side. Some of face’s key lines (i.e. eye browses) point towards a “vanishing point”. Once identified, the rest of his face is easy to draw in perspective, you only need to respect the above mentioned two basic  rules of perspective: vanishing point and receding sizes.

This is a way to estimate the perspective of a body (to include it in a cube) BUT unfortunately its author didn’t respect here the “vanishing points” of the cube. Good try though…


Based on my experience as portrait painter:

Profile is inscribedable in a square

  1. the human head is facing us vertically to the ground (proportions change when the subject is looking upwards or downwards) *
  2. the head is inscribed within a rectangle with approximate proportions of 2/3 or 3/5 (roughly those of a letterhead). I found these proportions after using many photographs of people with short hairs (or bald) to better locate the actual limit of their skull (haircuts are misleading)
    Note: when drawing a baby’s face this proportion is closer to a square’s: (roughly) 4/5.
  3. the ears are OUTSIDE of the rectangle (since they are floppy and their size/shape vary)
  4. the eyes are located at (roughly) 1/2  of the rectangle height (i.e. when faces are vertical to the ground)
  5. the length of the nose is (roughly) the same as the distance between the center to the eye  corner : they can therefore be inscribed within a circle whose center is situated between the eyes
  6. when still the mouth position can be found by drawing a circle inside the rectangle (diameter is equal to basis of the rectangle) – of course any expression (grin, sorrow etc)  will affect the size and position of the mouth…
* this explains why children (or adults who have kept this habit) tend to draw faces whose eyes are situated too high (therefore with a too short forehead): their point of view is as seen from underneath!

Picasso doing the same “mistake” as seen from a child perspective… Your choice Pablo!

Mona Lisa (Leonardo da Vinci)

Mona Lisa (Leonardo da Vinci)

Example(s) from my daughter’s:


Hannah’s Dad when she was 9 yo

Hannah Messer self portrait when 14 yo (2011)

Hannah’s Grandma  (2011)

Hannah’s Grandpa (2011)


Hannah (now Kitty) when 17 yo