Submitted by H.S. Kwok, OSA Fellow
Can anyone explain the following optical phenomenon?
I went to a garden in Guangdong over the weekend. They claim to have a window that can convert the outdoor garden scene from summer to autumn to winter depending on the position of the windows, which are made of blue tinted glass.
I’d like to share the three pictures that I took. The first one is the original summer scene, green trees and all.
The second was taken with one blue tinted glass window pane.
The scene does look wintery with the leaves appearing rusty in color and the white tops looking sort of like snow.
However, the most interesting is the third picture, taken with two overlapping blue tinted glass window panes. (The windows are of the sliding door type.)
The leaves turn red! The scene now looks like autumn. I cannot explain how the red color can come out with two blue filters. The leaves in the picture taken with two blue filters are redder than those in the picture taken with one blue filter. Strange. I saw it with my own eyes and took the pictures with a Canon DSC. Can someone please explain this?
H.S. Kwok, OSA Fellow
2007-11 November, Miscellaneous Optics