Wallpaper for my laptop

My wallpaper... carbon fiber. You need to tile it to make sense. It's good for low-light power user stuff (lots of windows, want a subtle wallpaper).

Also... tiling is incredible efficient and low memory usage. Good for laptops as big wallpapers do actually affect battery life, as do wallpapers that are mostly light colours.

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but, seriously, what VB said ^^, you want a dark background to save energy.
that's why notebook's where made for porn, not for surfing on "bright" google.

Not sure the 'light colours' use more power thing is relevant to LCD displays (it's certainly true for CRTs), I might be wrong but let me give you my thinking.

Unlike the phosphors in a CRT, an LCD display switches colours by applying a charge to the liquid crystal filled pixels - agreed? - but it does not change luminance, luminance is supplied by the backlight and even when held in a 'black state' (racist) the backlight is still switched on.

A completely black screen still has the backlight switched fully on, black on an LCD is not a lack of light (like it would be when you switch out the phosphors on a CRT) - it's just the liquid crystal held in a different state - and when held in the black state it is simply blocking the backlight.

Moreover, it takes more voltage to hold a pixel at black than at white - - - - from Wikipedia:

If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black.

So, a large(r) voltage gives you black.

I think it is a common idea (and reasonable - but wrong - one) that an LCD device emitting less light uses less power, but with an LCD display - which itself emits no light (the separate backlight does that job) this is not the case.

Without boring you with too much detail, it is easy to set up (at manufacture) an LCD display (with a backlight) so that it appears bright with no voltage applied and dark with a voltage applied. And that's what they do. The argument does not end there, there are a few other considerations, but it's enough to say having your screen black does not save energy on an LCD.