Natural light through the day and the year

The sun is the oldest and most powerful light source an image maker uses, and it is free, but it is not under our control. Its direction, height, color, quality and intensity change continuously through the day, through the seasons and with weather, latitude and surroundings. Landscape and documentary photographers plan their work around these changes; cinematographers schedule exterior scenes for particular times of day and use large tools to modify sunlight; and every image maker benefits from reading natural light accurately. This lesson covers the sun's path and elevation, how light changes from sunrise to sunset, golden hour and blue hour, overcast and weather, light in shade and from the sky, seasonal and latitude effects, window light indoors, and the tools used to plan and modify natural light.

The sun's path

Each day the sun rises roughly in the east, climbs to its highest point at solar noon (when it is due south in the Northern Hemisphere, which may differ from clock noon by an hour or more because of time zones and daylight saving time), and sets roughly in the west. Its maximum height depends on latitude and season. At solar noon, the sun's elevation above the horizon is approximately:

where δ, the solar declination, varies from about +23.4° at the June solstice through 0° at the equinoxes to −23.4° at the December solstice. In summer, the sun rises north of east and sets north of west, staying high for a long day; in winter it rises south of east, stays low and sets south of west after a short day.

Light through the day

As the sun moves, its light changes in several ways at once:

• Direction and height: low sun gives side and backlight with long shadows and strong modeling; high sun gives top light, short shadows and deep eye sockets.
• Color: at low elevations sunlight passes through much more atmosphere, which scatters blue (Lesson 2), so it becomes warmer, from about 5,500 K near midday to 3,000 K or lower near the horizon, while the shade lit by blue sky stays cool. Mixed warm sun and cool shade gives strong color contrast.
• Intensity: direct sunlight is weaker at low elevations, reducing contrast between sunlit and shaded areas.
• Quality: the sun remains a hard source all day on clear days, but near the horizon haze can soften it.

Midday light on clear days is often considered harsh for portraits and landscapes because of top light and high contrast, though it suits some subjects, such as graphic architecture, tropical water and strong-color images. Many photographers prefer the hours after sunrise and before sunset, when low, warm, directional light reveals texture and shape.

Golden hour and blue hour

Golden hour is the period shortly after sunrise and before sunset when the sun is low, roughly below about 6° to 10° elevation, giving warm, directional light with long shadows. Blue hour is the period of twilight when the sun is just below the horizon (roughly between 4° and 8° below), and the sky provides soft, cool light; the sky glows deep blue, and city lights and lit windows balance well with the sky, making it popular for cityscapes and architecture. Despite the names, their length varies greatly with latitude and season: near the equator the sun rises and sets steeply and both periods last only minutes; at high latitudes in summer the sun moves at a shallow angle and golden light can last for hours, while around the summer solstice in far northern regions twilight may continue through the night.

Overcast and weather

Clouds transform sunlight. A thin layer of high cloud slightly softens and cools the sun. A complete overcast turns the whole sky into one enormous soft source, with low contrast, soft shadows and even, cool light, around 6,500 K to 7,500 K, ideal for portraits, product shots outdoors and woodland scenes, though often flat for landscapes. Broken clouds create changing patches of sun and shade, dramatic for landscapes but challenging for continuity in filmmaking, where consecutive shots of a scene must match. Fog and mist scatter light, lowering contrast, simplifying backgrounds and creating atmosphere; rain darkens and saturates surfaces and adds reflections; snow acts as a giant reflector, filling shadows from below and fooling meters (Lesson 11).

Shade and skylight

Subjects in open shade, such as the shadow of a building with open sky above, are lit by skylight, which is soft and cool (often 7,000 K to 10,000 K or more under a clear blue sky). Open shade is a classic portrait location on sunny days: even, flattering light without squinting. The color of light in shade is influenced by surroundings: shade under trees picks up green; shade beside a red brick wall picks up warmth. Camera white balance must be set for shade, or the images will look blue (Lesson 7).

Seasons and latitude

Latitude and season change the length of the day, the height of the sun, and how long the useful low-angle periods last. In summer at higher latitudes, long days give extended golden hours but harsh high sun at midday; in winter, short days give low sun all day, long shadows and frequent warm light, with less time to shoot. Snow, ice and frozen landscapes add reflections and cold blue shadows. Image makers also consider seasonal factors such as foliage color, leaf cover (which changes the light in forests), haze from humidity or smoke, and the position of sunrise and sunset relative to the location.

In the United States, the range is large: around the June solstice, Seattle (about 47.6° N) has about 16 hours of daylight and long twilight, while Miami (25.8° N) has about 13.7 hours; in northern Alaska, the sun does not set for weeks in summer and does not rise for weeks in winter.

Window light

Indoors, windows are natural softboxes. A window facing away from the direct sun (north-facing in the Northern Hemisphere) gives soft, consistent skylight through the day, which is why painters and photographers have long valued north light studios. Windows with direct sun give hard, warm patches that move through the day. Window light falls off quickly with distance into the room (it behaves like a large source, falling off less steeply than the inverse square law at close range but noticeably over a few meters), so subjects near a window are much brighter than the room behind them, creating natural modeling and dark backgrounds. Sheer curtains diffuse direct sun; white walls and reflectors fill shadows; black fabric adds negative fill. Mixing window daylight with warm interior lamps creates color contrast that can be embraced or corrected with gels (Lesson 7).

Planning and modifying natural light

Image makers plan natural light with tools such as sun-position apps and websites, which show the sun's direction and elevation for any place and time, augmented-reality views of the sun's path over a location, weather forecasts including cloud cover, and scouting visits at the planned time of day. Film productions build schedules around the sun, shooting wide shots of exterior scenes when the light is best and using tools to maintain consistency for close-ups:

• Large silks and scrims overhead to soften and reduce direct sun on actors.
• Reflectors and bounce boards to fill shadows.
• Negative fill to add contrast under overcast skies.
• Neutral density filters on cameras to control exposure in bright sun.
• Lights such as HMIs and large LED fixtures to supplement or replace sunlight, for example to extend golden hour or to fake continuous sun when clouds pass.

Recording natural light conditions

For photographers and cinematographers, keeping notes on natural light at locations, the time, weather, sun position, readings and how the light looked, builds a personal reference that improves planning. On productions, scouting photographs taken at the planned shooting time are invaluable for the director, gaffer and production designer. Some crews use time-lapse cameras left at a location for a day to show exactly how light moves across it, which is especially useful for interiors where direct sun moves across walls and floors.

Natural light also has strong emotional associations that audiences recognize instantly: the low gold of evening suggests endings, nostalgia or romance; the cool blue of early morning suggests freshness or loneliness; harsh midday light suggests heat and exposure; and overcast light suggests calm, melancholy or ordinariness. Choosing the time of day for a scene is therefore a storytelling decision, and cinematographers sometimes recreate a particular natural light with artificial sources when the schedule does not allow shooting at the right time.

Finally, natural light and artificial light are often combined. Even when shooting mainly in daylight, a small reflector or LED can lift a face, and many apparently natural-light images in advertising and film rely on subtle additional light that viewers never notice.