A Black or a White Background, That’s the Question

Introduction

I’ve been working daily on computers for two and a half decades now, so there are a number of things I’m really careful about when it comes to caring myself. One of the most important is eye comfort. There has been a lot of debating whether green/orange on black is better than black/blue on white as far as screen readability is concerned. I’m not going to tell you which is best for you. I firmly believe that although both may really have advantages and drawbacks, there are so many factors that you have to put things in the balance and judge what works best for yourself. However, I’ll tell you what works best for me, and why, along with a couple of other tips.

To make things clear from the start, despite spending some 25 years with often 10+ hours a day in front of computer screens, my eyes are still seeing perfectly without any help (no glasses, no contact lenses). Maybe I’m just lucky. Maybe I have good genes. But most of all, I do care my eyes, and I always pay attention to the signals they are sending me.

Black backgrounds don’t save energy!

First of all, let’s debunk an old myth: black backgrounds don’t save energy on LCD monitors. Most people imagine that these monitors contain millions of little lamps that light the screen.

Actually, LCD stands for Liquid Crystal Display, “Liquid Crystal” is actually the same technology than these good old black and white watches used back in the 70s and 80s, except that the black pixels are much smaller than back then, and there is a white light turned on behind them so that the screen will emit light.

TFT screens or AMOLED screens (on some cell phones such as most Samsung ones for instance) do have lots of LEDs which are tiny electronic lamps, but they are rare on computer screens.

So with that in mind, given that turning a pixel off on a LCD monitor actually costs energy to polarize the crystal, black screens don’t save energy, it’s just the opposite. That’s because unlike what people think, there aren’t millions of little LEDs in the monitor to power.

So the “black-energy-saving” stuff is just marketing nonsense. Now, if you have an old cathodic display from the 90’s, it will save you some energy (some say up to 30%). And on tablets and cellphones with AMOLED screens, yes it does save battery to have a black background.

That said, my eyes’ health is much more important to me than saving 1% energy, sorry for the ecologists! So let’s ditch the “green” argument.

Contrast and Brightness

If you really want to save energy, you have to play with the brightness of your screen. The brighter it is, the more it will spend (because what brightness does is just controlling the back light of the screen, making it more or less powerful).

Besides, I’ve always noticed that my eyes were getting more tired when the brightness was up and the contrast was down. You may not know it, but you can calibrate your screen to change its brightness and its contrast. This makes a big difference in terms of eye fatigue at the end of the day. My advice: push the brightness as low as possible (if there’s a 0 on the scale, try that!), and then push the contrast to a level that seems comfortable. For instance, I have two screens here, both are on brightness 0, as for the contrast they are at 91 and 51 (out of 100), and they look pretty much the same with these settings.

Temperature

What the hell has Temperature to do with a screen? Is it going to overheat? Temperature is simply a way of describing the type of light you’re seeing. Without getting technical, the more you see it red/orange, the “hotter” it is. The more blue it gets, the “colder” it becomes.

One thing to know is that our eyes don’t like the blue color. Actually, it damages them. So the less blue comes to your eye, the better, especially from LED-lit screens (such as some tablet or phone screens), which are particularly violent.

Oh, and if you don’t believe changing the settings can affect your eyes… just by changing some presets (I’m not even speaking about changing the brightness/contrast here), here’s what I get on my screen (captured with a microscope directly on the same region of the screen, which is supposed to be white):

pixels

Do you believe this cannot affect your eyesight?

My advice on most screens, try to get a warm color. It will give less blue to your eye, and the colors will look warmer and more relaxing.

It should be black on white – that’s what paper looks like!

Some are saying that black on a white background is the most “natural” one because it’s what paper looks like.

Well, sorry, but people really started reading on paper one or two centuries ago (not speaking about the extreme minority of literate people who’ve been using paper for millennia, the vast majority never had regular daily access to paper), so I doubt that our genome really had the time to adapt to that. No, “Mammoth” was not written on white sheets of paper in prehistorical times.

Second, what you see on paper is reflected light, whereas the light coming from a screen is directly emitted by the screen, that’s a critical difference. So for electronic readers that don’t emit light like paper (the Kindle, for instance), yes, black on white is similar to paper, but it isn’t on a computer screen.

I work on a screen several hours a day. I have some breaks, but at the end of the day the accumulation of hours is there. And I can clearly say that, at the end of the day, I feel much more tired when I’ve spent the day in front of… a white screen. That’s a simple fact, from my own experience. Again, I spend a lot of time in front of the screen – it’s my job, and my passion!

But hey, that’s only my own experience. Maybe yours could be different. For instance, if you have mild astigmatism, like a lot of people, black on white is probably better for you (unless you’re willing to zoom a little on a black background), because a dark background forces the iris to open more and makes the astigmatism stronger (that’s a story about errors in lenses – the more the light is focused in the center of the lens, the better the image ; but when the light hits the outer parts of the lens, you get more chromatic aberrations).

So again, there is no absolute. “Listen” to your eyes!

Take the highest resolution for your screen

My philosophy (given by my father) is that the more you make your eyes (and your brain, for that matter!) work out, the better you will see. So I use the smallest fonts I can read comfortably (without needing to open them more than needed), and always use the highest resolution of the monitors in order to get the finest details.

Here’s the result: what I’m comfortable with on the left, what most people are comfortable with on the right. No judgment. Just what feels comfortable.

textblackvswhite

Light prevents sleeping

One last warning to all white screen lovers, stay away from your screen in the evening. Studies show that looking at a white screen decreases the production of melatonin, so being in front of a white screen is probably going to affect your sleep.

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