Shuang Li at Easel, in rural Northwestern China, plein air painting
Shuang Li at Easel, in rural Northwestern China

The following is an excerpt from Shuang Li’s new book, “Watercolor Plein Air Basics: A Guide to Outdoor Watercolor Painting.” Meet Shuang Li in person at the 10th Annual Plein Air Convention & Expo in beautiful Denver, Colorado, May 21-25, 2023!

Capturing the Light en Plein Air

by Shuang Li

Shuang Li, “Waiting at the Club,” 2016, watercolor on paper, plein air painting
Shuang Li, “Waiting at the Club,” 2016, watercolor on paper, plein air, 15”x22”

Understanding How Light Changes: Plein Air Painting for Beginners

Before going outdoors, you need to understand the biggest difference between painting in the studio and painting outdoors is the LIGHT condition. When painting indoors in a studio the light does not affect the results when we paint for longer periods of time, regardless of the subject. When outside, the natural light changes constantly and affects how we see the subject matter and surroundings.

The changing light is affected by the time of the day:

  • early morning
  • midday
  • evening

…And the weather conditions:

  • sunny
  • overcast with different cloud coverage
  • fog
  • rain
  • snow

Adding location variations and seasonal conditions, an artist may face complex situations with multiple variables at any given moment. No wonder many beginners feel it is challenging or intimidating to think about these complications even before setting up an easel to paint.

Here are some explanations to help the developing plein air artist better understand the use of light when painting plein air.

How Light Changes in the Day

If the artist stands at the exact same position to see a subject matter for the duration of a day, he or she will find that in early morning, when the sunlight is coming from a lower angle of the east side, the subject matter will generate a longer shadow in the opposite direction of the light source.

See the example of the house in this illustration below. It is the same in the late afternoon, except the long shadow moves in the opposite direction of the morning. At high noon, when the sun is directly above the subject matter, the light generates the shortest shadow, if any, of the subject matter. When evening comes and the sun nearly drops below the horizon, one may only see a silhouette of the subject matter that merges with the shadow of itself.

Examples of how light changes when you're painting outdoors
This illustration explains how the light source and the time of day affect the lighting on a subject matter in plein air painting. Understanding the way the light “moves” with time helps to choose locations wisely before starting to paint.

Among the four conditions, the high noon position is the least favorable for artists to paint. It makes the subject matter look “overexposed” because of the light source angle directly from the top. It also generates the shortest visible shadow directly under an object, making the various shapes harder to connect. This creates a painting that may have many scattered or isolated small shapes. Longer shadows connect more shapes and lend unity to a plein air watercolor painting.

Shuang Li, "Lagoon in February," 2021, watercolor on paper, plein air, 11”x15”
Shuang Li, “Lagoon in February,” 2021, watercolor on paper, plein air, 11”x15”

Helpful Links:

Become a better outdoor painter today when you get the FREE e-Book for artists, “240 Plein Air Painting Tips.” [click here]

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