[Leica] An unusual visual phenomenon

[lrzeitlin at gmail.com (Lawrence Zeitlin)]

Yesterday afternoon, when shoveling our recent 15" snowfall off the
driveway, I paused at the mailbox to get the day's mail. I set the letters
down on the snowbank to close the box when I noticed that all the white
envelopes appeared a pale shade of blue. When I took them in the house they
appeared normally white. While I have no definitive explanation for the
"blue" envelopes, I have written before that the eye, mediated by the brain,
does not see reality but sees what it expects to see. We alter the visual
scene until it conforms to our expectations. Colors are viewed in their
"proper" hues despite ambient illumination, shapes are altered, sizes
changed to offset their diminishment by perspective, and so on. Reality is
in our mind, not in the objective scene.

All I can suggest is that after a couple of hours of shoveling I expected
the snow to be white despite the fact that it was yellow tinged because of
the late afternoon sun. By shifting the color balance of the scene to meet
my expectations, perhaps the truly white envelopes were shifted into the
blue. Does anyone have an explanation?

Larry Z