All light is not created equal. I say created, because there are many types of light that are manufactured (like light bulbs) in addition to the light we get from our local sun. Even the light we receive from the sun does not appear to us the same all the time.
This issue comes up regularly in my own work when I do product photography, especially when it is critical to replicate precise colors for logos and branding. However, sometimes its not so much color accuracy that is important to this type of photography, but rather the color of the light – namely warm versus cool.
This is something you should experiment with for landscape and portrait photography as well. Depending on the time of day you shoot, you can achieve different moods with your photographs. Photograph the same subject in the morning, and then again later in the afternoon and compare the results. As I have learned, one type of light might lend itself better to the subject you are photographing.
Next Wednesday in Light & Color Theory Part II, we will more closely examine the wide gamut of color sensitivity your camera must interpret. This is called White Balance. Finally two weeks from now in Part III, we will explore ways to achieve accurate white balance and ways of using white balance creatively.