Cool Desktop: Spectrum of a Tree

My wife has been using this image as a desktop back­ground for about a year now, but recently I took a good look at it.

Ini­tially I thought this was simply a photo of a tree in sil­hou­ette, sliced, col­our­ized and laid out as you see it.

But on closer inspec­tion, it seems that these are shots of the tree, at vari­ous times and sea­sons, with dif­fer­ent col­oured sky in the back­ground. The web­site does­n’t really have detail on how the image was created.

The pho­to­graph­er also cre­ated Spec­trum of the Sky — but I like the Tree better.