Does latitude itself change daylight color, or is it mainly sun angle and atmosphere?

Asked 5/20/2013

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If I photograph under otherwise similar conditions in different parts of the world, does latitude by itself change the color of sunlight enough to affect white balance? For example, would daylight at the equator, tropics, and higher latitudes look different if the sun is at a similar height in the sky? How much of any difference is really caused by latitude versus time of day, season, altitude, and atmospheric conditions? And when traveling, is there anything special I should do in camera to compensate?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

13y ago

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The color of sunlight reaching the surface changes based on the thickness and quality (in terms of things like particulate matter and water vapor suspended in it) of the air it passes through. Whether the sun is at an angle 30º above the horizon because it is noon in winter at a high latitude or because it is 4 p.m. in the tropics doesn't make much difference if both locations are at the same altitude. When the sun is at a low angle in the sky, such as when setting or rising, the rays must travel through much more atmosphere than when at higher angles in the sky. The condition of the air those rays are passing through can have a dramatic effect on the quality of light that reaches the surface.

The seasons affect the light for a particular location because the amount of moisture and particulates in the air will vary from season to season in many locations. If a place is outside the tropics then the maximum angle of the sun in the sky is lower in the winter than in the summer. This difference increases dramatically as you approach the arctic circles.

In places that have snow covering the ground in the cooler months, the light reflected from the snow will look much different than the same light reflected off of lush green meadows which will look different than the same light reflected off of urban concrete, a sandy beach, or a dusty desert - even when the sun is at the same angle in the sky.

Which of the above factors is most influential varies with the situation as well. In the middle of the Sahara desert, the atmospheric conditions do not vary that much, so the angle of the sun is normally the largest variable - at least until a dust storm develops. In the Pacific Northwest of the United States, cloud cover is highly variable and can potentially be a greater influence than the angle of the sun. There's not much difference between overcast at noon and overcast two hours before sunset. Above the timber line on an exposed Rocky Mountain peak the light will be much different than descending just a few hundred feet into a lush forest of green.

You can always correct for the differences in the temperature and amount of light using colorimetric tools and varying the exposure value. But why would you want to make every place you go look exactly the same?

Does Earth's latitude affect the color of light?

Only indirectly, as the latitude determines the sun's angle in the sky for a given time on a given day, and also influences weather related environmental factors such as atmospheric contents and ground cover.

Originally by user15871. Source · Licensed CC BY-SA 4.0

user15871

13y ago

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AI Answer

Generated from our catalog & community — verify before relying on it.

Latitude is not the main cause by itself. What matters most is the sun’s angle in the sky and the atmosphere the light passes through. When the sun is low, its light travels through more air, which usually makes it warmer and less intense. If two places have the sun at a similar elevation and similar altitude, the light can be very similar regardless of latitude.

In practice, atmospheric conditions often matter a lot: dust, haze, water vapor, clouds, and seasonal air quality can change the color of the light dramatically. So differences between locations are usually no greater than the differences caused by time of day or season.

Yes, it can be corrected. The normal approach is to set white balance appropriately, or use a gray card for a more accurate custom white balance.

When traveling, you usually do not need a special latitude-based camera setup. Just evaluate the actual light where you are and adjust white balance as needed. If you want consistency, shoot RAW and/or use a gray card.

UniqueBot

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13y ago

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