Friday, 17 April 2009

Whiter than white?

Looking at the title, you could think that I am trying to sell you some washing powder, but this is an article about using white in our paintings (Although, I write a little bit about washing later on).

Let’s go straight to the point: it is most unlikely that you will see pure white in nature. It’s all a matter of contrast and reflected lights on white objects.

White and simultaneous contrasts

The way we perceive based on context was brought home for me when I visited the last year
The Exploratorium in San Francisco. They had an experiment in the section on “seeing” where they were displaying in the dark a succession of lighted squares. When the first one appears, it looks white. Then, the second square pops-up. You see it has a lighter shade and, by comparison, the first one looks grey. It goes on and on… and you cannot believe your eyes that each new square appears lighter than the previous one.

This exhibit focuses on how the environment affects the way we see everything: colour, tone and brightness. The same goes with the light areas of your paintings.

The checker shadow illusion is also a striking way to remind us that our brain is easily tricked into seeing as different tones that are identical, based on the context.

Square A and B seem to be of a different shade

The two vertical bars show you that, in fact, square A and B share the same shade of grey

You can read an
excellent explanation of this illusion by Edward H. Adelson from the Department of Brain and Cognitive Sciences at the Massachusetts Institute of Technology.

What colour is your white?

White surfaces act as a screen where the coloured light and surrounding object can reflect. For this reason, you will have bluish whites or yellowish whites depending on the time of the day and the quality of the light.

Using a palette of light colours rather than pure white out of the tube makes your painting more interesting in subtle ways. The modulation creates movement and interest and stays closer to real life.

In fact, there may be some cultural influences on how we perceive the quality of the tinted white as white. Washing powders contain some agents to make white a little bit blue. Historically, people noticed that it did not matter how well they washed them, white fabrics always had a slight yellow shade. Physicists found that you could neutralise this yellow colour by adding some ultramarine blue to the rinsing water. This habit stayed and we today perceive white fabrics with a slight blue shade as fresher and whiter.

In practice

We talked about how our eyes perceive reality. How does that translate in practical terms?

  • It is a good idea to use a piece of white card to judge the brightness and whiteness of an object you are painting.

  • Remember that pure white is rare in nature and that a good way to make light colours appear lighter is by simultaneous contrast (of tone, colour and brightness).

  • A coloured ground, in particular with a mid-tone or neutral colour, will make it easier than a white ground to set the lighter tones at the correct level.

  • Tinted whites (with blue, pink, yellow, etc.) offer endless possibilities to make your light areas more interesting.

To end this article, I will leave you with what Ambroise Vollard remembered in his book “Recollection of an Art dealer”:

“Later on, I happened to hear Renoir talk about a white on white effect that he was trying to render.
- It is pretty difficult, he said, but nothing is more exciting to paint nor provides a nicer effect.”

Vollard (and probably Renoir) did not explain what this effect consisted of, so we will all have to go to the museums and study carefully any Renoir’s painting we can find in order to try to see and understand this effect.

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