But aren't CRTs on the way out? We could in this case just wait for the problem to go away, right?

It saves power on LCDs too, just not quite as much because they don't use that much in the first place..

But since the total number of computers in the world keeps going up, even with LCDs we'll keep using more and more power for displays.

This thing, I guess, is more conceptual than anything, but I like how it reminds us that small choices can have big impacts.

Actually, it doesn't save any energy on an LCD. There, the backlight is on all the time, for every pixel, and the LCD panel itself just changes color and opacity to determine the emitted image. This only makes a difference for display technologies where the amount of light originally generated is determine on a per-pixel basis, namely CRTs, OLEDs, and Plasma displays.

I'm all about saving energy and I enjoy new ways of doing so, but sometimes you have to draw the line. As a graphic designer, I can tell you that all black backgrounds are not a wise choice b/c reversed type (white) is harder to read on them. So, where you might be saving a little energy, you're straining your eyes more. And think psychologically about the implications of staring at a black screen. Let's save energy but not jeopardize our health. There's many other ways to save energy. ... i just changed all my light bulbs to CF's yesterday.. woowoo

Why don't you try http://www.ninja.com

It uses the google engine but with a black front end.

J

We created a custom search engine based on this. http://google-black.blogspot.com

So why isn't treehugger.com black?

--
editor note: Because we didn't think of that when we created the design.

But as has been pointed out, black isn't very good for usability. But the palette linked from the post (near the end) is definitely something we'll consider the next time we redesign. It might not happen, it's not the only factor, but if we can do it, it certainly would be cool.

Wow..that's incredible to think that one simple change like that could do that much.

Thanks Dymaxion, I didn't know that!

+1 informative :-)

is there an option to forward articles?

That's a pretty cool idea. If that only works on CRTs, is there anything you can do to tweak LCDs? Anyone know the default color for them?

This issue manifests differently on LCD monitors, as I understand it, since the backlight on an LCD is perpetually on, at whatever brightness you have your monitor set to, independent of the colour being displayed. The backlight performs the function of illuminating the pixels, rather than each pixel being independantly luminous, as with CRTs where you have 3 cathode guns (one each for Red, Green, and Blue) per pixel. In a CRT, the more light coming from each gun, the more wattage consumed. In an LCD, all of the luminance comes from a single fluorescent backlight, and the watt-consumption, therefore, should be nominally consistent, regardless of what's on the screen.

As for making all websites black I agree with BrownB, and think that it might be a false economy - all of the energy saved will just need to be channelled right back into the manufacture of eyeglasses and muscle relaxants for all of the poor suckers whose eyes get screwed up from eye strain. I'm serious - it's one of the most universally accepted tenets of the good design of text-biased information for screen or print for a large audience that you not use light-on-dark as your primary format.

Some of us voluntarily decite to ditch that convention when executing personal design work, especiallly when it's destined for a constrained audience, but in the case of a page like google (or treehugger, for that matter, which is incredibly text and information-dense), it's just not plausible, or even a very good idea.

An alternative? Control the light levels in your working environment, and reduce your screen brightness a bit.

A few comments here. It is true that it makes no difference energy wise what is displayed on an LCD screen, and that, generally, CRTs are "going away". However, the new types of display such as plasma and OLED are the wave of the future. So what we will see is a trend towards lcds and then a trend back to 'white light is costly' devices.

I don't agree that staring at a black screen increases eye stress, although I don't truly know; there have been few studies on this. I do know that I stared at a black DOS screen with green or amber lettering for half of my career, and no one seemed to complain then. Could be that Black on white is nothing more than a freak byproduct of the printing process - that just happened to be what the materials were?

mark

Well, one thing people could do is reduce the brightness of their screens, whether CRTs or LCDs. This does reduce energy consumption and can do so considerably. I don't know the numbers. But I know from personal experience that it saves energy. My house is powered by sun and wind, and I have two sets of wires in my house - a 12VDC wiring set (like in a car) and a 240V AC set. I sometimes use my laptop and a small CRT tv plugged to the 12 V DC wiring but sometimes use a small inverter to connect them to the wiring. The inverter beeps when too much energy is being drawn through it. The tv and laptop cause it to beep when the display is at high brightness and doesn't when at medium brightness. It is such a simple thing to do. Just adjust the brightness of the display - it takes 2 seconds.

Plenty of designers successfully use black with white type. It isn't like massive columns of text will be set in white-on-black, it's just Google results. Really, I think raising this to a "health" and psychology issue is a bit much. The evidence is all debatable and could easily be attributed to bad settings on CRTs anyway.

Also, highway signs are dark green with white for a reason: it is the easiest color combination to read. And they don't even use a serif typeface, which would theoretically enhance readability.

If you're on OS X you can just invert your screen colors on the fly using CTRL+ALT+APPLE+8. If you're in a low-light situation, viewing white text on a black background is way easier on the eyes in my opinion.

This is an interesting article:

http://www.ischool.utexas.edu/~adillon/Journals/Paper%20vs%20screens.htm

from the section called "image polarity":

"A display in which dark characters appear on a light background (e.g., black on white) is referred to as positive image polarity or negative contrast. This will be referred to here as positive presentation. A display on which light characters appear on a dark background (e.g., white on black) is referred to as negative image polarity or positive contrast. This will be referred to here as negative presentation. The traditional computer display involves negative presentation, typically white on black though light green on dark green is also common.

Since 1980 there has been a succession of publications concerned with the relative merits of negative and positive presentation. Several studies suggest that, tradition notwithstanding, positive presentation may be preferable to negative. For example Radl (1980) reported increased performance on a data input task for dark characters and Bauer and Cavonius (1980) reported a superiority of dark characters on various measures of typing performance and operator preference.

With regards to reading from screens Cushman (1986) reported that reading speed and comprehension on screens was unaffected by polarity, though there was a non-significant tendency for faster reading of positive presentation. Gould et al (1986) specifically investigated the polarity issue. Fifteen subjects read 5 different 1000 word articles, 2 negatively presented, 2 positively presented and one on paper (standard positive presentation). Further experimental control was introduced by fixing the display contrast for one article of each polarity at a contrast ratio of 10:1 and allowing the subject to adjust the other article to their own liking. This avoided the possibility that contrast ratios may have been set which favoured one display polarity. Results showed no significant effect for polarity or contrast settings, though 12 of the 15 subjects did read faster from positively presented screens, leading the investigators to conclude that display polarity probably accounted for some of the observed differences in reading from screens and paper. "