Not sure whether to put this in CS or GQ, but since my curiosity is based in art, let’s start it in CS.
In what way is morning light different from evening (or late afternoon) light? Artists seem to really know the difference. I can sort of tell the difference myself, but there’s no way I could explain it, or even really be sure of what it is I’m seeing.
So, two questions:
One, how would you describe the difference?
Two, what causes it? Logically, one would think that there would be no difference at all. If the Sun is low in the sky, why would it make a difference if it’s in the east or in the west?
It’s definitely different. Clearer somehow. My thought is that the setting sun is shining through a partion of an already heated atmosphere; a rising sun shines through a portion of the atmosphere that has cooled. The light would refract differently and possibly pollens and pollution would be less. But that’s just a guess, I’m not sure if a relatively few degrees of temperature woudl really make much of a difference.
Spending a lot of time in Florida it always seemed odd that when watching a sunset on a clear day on the gulf coast you could watch the sun as a glowing near perfect sphere slowly drop below the horizon.
However, even on the clearest of days on the Atlantic coast when the sun would rise it would never look like a sunset in reverse. There always seemed to be some type of ocean fog that needed to be burned off before you got a good shot of the sun.
Unfortunately, it doesn’t seem to make much distinction between morning and evening light, just “sun just below horizon” vs “sun just above horizon” light. Personally, I don’t think I could reliably tell the difference between sunrise and sunset lighting in a photo. The only thing that tips me off to sunrise is a misty/dewey appearance.
It explains Magic Hour nicely. It doesn’t explain the difference between morning and evening, though.
Interesting ideas about fog, dust, and temperature. In working with some nautical navigation stuff, there are adjustments that need to be made because of temperature, although only at extremes. But that does show that it is a factor in refraction.
One would think, though, that if temperature had that much effect on the light, then we’d see things very differently on a Fall day than on a Summer day. So different, in fact, that our sight would be impaired. Clearly, that’s not the case.
Morning light comes from the east, evening light come from the west.
But more seriously, I think that there would be differences in the air quality because of the sun being up all day in the evening. In the morning, it’s been dark all night and water moisture would have condensed out of the air, while in the evening the sun’s been shining down all day and would have caused more water to be in the air.
To me, morning light is clearer, more yellow in tone. Evening light is redder (more red?).
The shadows are different too, and not just where they are placed. The evening shadows are deeper, gloomier-a herald of the night to come, if you will. The morning shadows are brighter, more “transparent” or “lit up” (if one can say that about a shadow).
It must have to do with the angle of the sun in relation to the horizon, but it’s been 20+ years since I had earth science.