# What is the most effective way to setup a Notebook with transparent background but solid contents?

I know there is a Notebook option WindowOpacity can be used to adjust the opacity of a whole notebook. But what I want is keeping the text and graphics and so on being Opacity[1] while the other parts of the window being Opacity[0.3], which may look like (the pic is roughly produced by photoshop):

I guess this effect might be achieved by capture the screen prior and set it as the background of a Cell/Cells. But even if that is applicable, it must be very inefficiency.

My questions are: how to achieve this transparent effect in Mathematica (maybe with some help from external applications)? and how to do it effectively?

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Very cool. Didn't know you can change the opacity. – Mike Bantegui Jan 19 '12 at 5:20
The documentation for Background says "The setting for Background can be any color or opacity specification" so I thought you could locally set Opacity at the cell level to override the WindowOpacity and get the sort of effect you want but I get an error message when I use Opacity with Background. – Mike Honeychurch Jan 19 '12 at 6:26
Fixed the background error but local Opacity settings at the cell level are being overridden by the WindowOpacity. Interesting problem. – Mike Honeychurch Jan 19 '12 at 6:37
@MikeHoneychurch Yes the window level option will override others. I'm working on a GUI application and trying to make it cooler.. – Silvia Jan 19 '12 at 9:47

SetOptions[InputNotebook[], Background -> Opacity[.75, Red],