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Plein air painting

Episode 6: How To Paint Light – One Little Known Trick And One Common Trap to Avoid

Reflected Light

The light on this street in Marrakesh was incredible. The shadows seemed to glow as if they had some magic light source. It seemed so intense. But how to paint light? That was my challenge in this painting: how to paint the light. Here are two useful tips I discovered.

Above is some video I took of the experience of creating the painting below. The video is a bit long and unedited, but will give you an idea of the reality of what I was dealing with, as well as showing you some of the progression of my painting. Hopefully it will give you some ideas for how to paint light.

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Cat. No. 1319 Arset el Mellak, Marrakesh – 22cm x 30cm – Oil on Linen

How To Paint Light Tip No. 1 The Washes

how to paint light

This is somewhere in the early process of how I started the painting. I was using transparent oil washes. I started off using pure pigments thinned with odorless mineral spirits in an almost a watercolor-like technique. And only later moved to more opaque pigment by adding titanium white to my colors. At this point I was exploring how to paint light in the shadowed street in the background before attempting any detail. The effect of all these washes was to create a multi-colored imprimatura.

How To Paint Light Tip No. 2: Ignore the Photograph

There was no way to capture the feeling and effect of this light in a photograph. You had to be there to see it. If you look at this photograph you don’t get the proper feeling of light. This is because the shadowed area of the street is quite dark in the photograph.

In reality, when you are actually there, the iris of your eyes adjusts to the shadows to let in more light, and the extremely strong reflected light makes the shadows appear much lighter and saturated in color. Actually the painting captured the feeling quite well. The photograph does not come anywhere close.

So in order to paint light you need to have some plein air experience so that you know how to interpret a photograph.

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Above is a photo of the actual scene I was painting.

The Dynamic Range Camera Problem

In order to learn how to paint light, if you work from photographs you need to understand the dynamic range camera problem.

The problem with photography

When we look at shadows, our eyes adjust to let in more light (our pupils dilate). This means that we can see color in shadows. When we look back at a bright light, our eyes adjust to block some of the light so we can better see the light areas.

However, the camera has a limited dynamic range compared with the human eye. Each time you take a photograph of a scene that has areas that are very dark and areas that are in bright sunlight you can either:

  • get the shadow colors accurate, but the areas in bright sunlight will be ‘washed out’. That is to say they will appear white and have no color in them, when in reality they would have a definite color and hue and a much higher saturation, or
  • get the bright light colors accurate, but at the same time the areas in the shadows will appear black. They will have no color in them, when in reality they would be a gray color with a definite hue.

The solution

There is not much you can do about this problem, which is why plein air paintings are so much livelier and real than studio paintings made from photographs. Some suggestions are:

  • use a high end camera with a high dynamic range
  • use the HDR setting on your camera or smart phone
  • take two photographs, one exposed for the darks and the other exposed for the lights
  • if you take only one photograph, under expose it a bit so that the lights retain their color. You can then use computer software to retrieve the colors in the shadows. You cannot do it the other way around. If you expose for the darks and the whites are ‘washed out’, you cannot retrieve them in software.
  • use the Zone System.

What the eye can see

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What the camera can see relative to the human eye

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Implications for color matching

Now this is where things get complicated.

Painting indoors

When painting indoors in a room that has no direct sunlight, matching colors is relatively easy. The same amount of light falls on the subject as your painting.

This means you can hold patches of paint up to your subject to check they are the same as the color spot on your subject (usually a still life, but it could be a portrait). Since the same amount of light is falling on your subject as is falling on your painting, you will very easily be able to match the colors and achieve a very highly realistic still life painting. This is the trick that methods such as ‘The Carder Method’ (now marketed as something else), and a lot of painting courses on the internet use. Easy stuff!

Painting plein air

This method completely falls apart when painting plein air. The reason is because of this common painting rule:

You will perceive a black object that has light falling on it to be lighter in value than you perceive a white object in the shadow.

(Some artists phrase this rule as: “the darkest dark in the lights is always lighter than the lightest light in the darks”)

In other words black can be lighter than white!

Conversely:

You will perceive a white object that is in the shadow to be darker in value than a black object that has light falling it”.

(Some artists phrase this rule as: “the lightest light in the darks is always darker than the darkest dark in the lights”)

This means that if your painting is either all in the shadow or all in the light, and your subject is half in shadow and half in light, the system of matching swatches of color with your subject cannot work. So that nice simple method of color matching completely falls apart.

In other words white can be darker than black!

This is why a lot of really good still life painters fall to pieces when they paint outdoors. Their color matching technique no longer works outdoors.

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