Why computer screens are not black ?

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plakhapate

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For saving power Google has started www.blackle.com where black screen is the background instead of white screen.

Hence if everybody does this we will save lot of power globally.

This will help in solving Global Warming .

Also black screen will not damage our eyes.

This information should be spread to all with immediate effect.

P.J.LAKHAPATE
plakhapate@rediffmail.com
 
Excellent idea...thanks!

White print on a black background is easier on the eyes.

Sciforums should follow suit.
 
This only works if you have a big CRT-style monitor. If you have a flat-panel LCD type monitor, it doesn't save any power.
 
Any screen that emits light is doing so by way of energy conversion. Black not actually being an emitted light but the absence of any light emission obviously doesn't cost energy. So it matters not if you use CRTs, LCD's or even projectors you'd still save energy.

In fact if you wanted to go further you could suggest what portion of the spectrum is the cheapest on energy for creating into light. I wouldn't entirely be sure without testing, probably something like red.
 
Well, computer screens are black. At least mine are...

Does that answer your question?
 
Stryder said:
Any screen that emits light is doing so by way of energy conversion. Black not actually being an emitted light but the absence of any light emission obviously doesn't cost energy. So it matters not if you use CRTs, LCD's or even projectors you'd still save energy.
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False. The light in the back of LCD monitors is always on and emitting white light - there is only one light source for the entire monitor. The monitor displays different colors on different areas of the monitor by rotating tiny liquid crystal pixels that sit in front of the light to block different regions of the color spectrum, so that only the desired colors pass through. When an LCD monitor is displaying back, it does so by setting the crystals to block *all* regions of the spectrum - but the power-consuming white light is still on all the time, unless your monitor goes into some sort of power saving sleep/standby mode. In fact, it actually uses slightly more power for an LCD monitor to display black than white, since each LCD pixel takes a tiny amount of energy to keep it in "blocking all the light" mode. The same is true for LCD projectors. Only CRT monitors save power by displaying black instead of white.
 
Who cares, the fact is it looks a hell of a lot cooler.

Plazma, make everything go black, please (autocratically - this doesn't need a debate or a silly vote :rolleyes:).
 
First, that website is NOT affiliated by Google in any way, other than using it's Custom Search feature.
It was probably started as a spin-off from Google's Earth Day setup; which featured a black background instead of white. However, in answer to why they don't keep the black all the time, Google stated that modern (LCD) monitors consume the same amount of power displaying black as they do white; as Nasor pointed out.

Even that site's source (for its claim that black saves power) states that the difference between max and min consumptions for black and white was a mere 103-108%. And of course, the source is 6 years out of date.
It also states that the back-light is the primary source of power-consumption, and hence, brightness would have a much larger effect (though that variable was not tested.)

Further more, and this is in accordance again with what Nasor posted, the following (quick Google search) page tested the two search pages
http://techlogg.com/index.php?option=com_content&task=view&id=360&Itemid=9
that of the LCD monitors we tested of size 22-inches or less, all showed an increase in power consumption using Blackle... ... the power consumption difference between Google and Blackle on all 23 LCD monitors was as small as you could get – an increase of 100mW (0.1Watts).
Click to expand...
emphasis mine.
And the they also tested backlight consumtion, which according to them is 2/3 of the LCD consumption.

All that said, the black is easier on the eyes.
-Andrew
 
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Nasor said:
False. The light in the back of LCD monitors is always on and emitting white light - there is only one light source for the entire monitor. The monitor displays different colors on different areas of the monitor by rotating tiny liquid crystal pixels that sit in front of the light to block different regions of the color spectrum, so that only the desired colors pass through. When an LCD monitor is displaying back, it does so by setting the crystals to block *all* regions of the spectrum - but the power-consuming white light is still on all the time, unless your monitor goes into some sort of power saving sleep/standby mode. In fact, it actually uses slightly more power for an LCD monitor to display black than white, since each LCD pixel takes a tiny amount of energy to keep it in "blocking all the light" mode. The same is true for LCD projectors. Only CRT monitors save power by displaying black instead of white.
Click to expand...


When my computer is in "Power Save Mode" the screen is less bright to conserve energy.

So I agree there is still energy being used on a black or less bright screen, but
not as much.
 
Regardless of the energy question...black screens are just easier on the eyes.

Another vote here for black-lighting Sciforums!
 
Carcano said:
Regardless of the energy question...black screens are just easier on the eyes.

Another vote here for black-lighting Sciforums!
Click to expand...

I made a thread suggesting a dark background for Sciforums which went, more or less, unnoticed.

A dark (preferably black) screen is much easier on the eyes (especially at night).
 
Hip Hop Skeptic said:
When my computer is in "Power Save Mode" the screen is less bright to conserve energy.

So I agree there is still energy being used on a black or less bright screen, but
not as much.
Click to expand...
The point is that if half your screen is displaying black and the other half white, you don't save any power over having the entire screen display white. You can save power by lowering the overall brightness of your screen, but it still won't matter what the screen is actually displaying.
 
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