Saanvi and Keiji are standing in a garden at 12:00 noon. Saanvi is standing directly beneath a short flagpole with a flag at the top, looking up at it. Keiji is standing a few steps to the side, far enough away that the sun is behind the flag when he looks at it. Saanvi tells Keiji that she cannot see the flag's color because the sunlight is shining directly in her eyes. Keiji, looking at the same flag from his position, says he can see the flag's color clearly. Why can Keiji see the flag's color without the same difficulty as Saanvi?
Keiji can see the flag's color clearly because he is standing such that the flagpole and flag are between him and the sun. From his perspective, the flag is backlit by the sun, which creates a contrast that outlines the flag, making its color visible against the bright sky. However, Saanvi is looking up at the flag with the sun directly behind it from her viewpoint, which means she is looking into the sunlight, causing glare and making it hard for her to discern the color of the flag as her eyes are overwhelmed by the brightness of the sun itself.