Dark Mode

Those monitors were all dark mode. That is, the screen was all dark (like my website) and the text (no graphics back then) were created by an electron gun behind the glass front. Basically, an old-school TV set but adapted for computer use. The text was usually green because green is a primary color, it's easy to see, the green phosphors were cheap and high quality, and could be created with a single electron gun.

Color monitors would soon hit the scene. They generally used white text on a dark background. Not unlike what you are seeing right now.

So, why is everything "light mode" now? What happened to dark mode?

WYSIWYG (wut??)

Unless you're above a certain age and a geek, you could be forgiven for not knowing what that jumble of letters mean.

WYSIWYG (pronounced "wizz-e-wig", the i's are short) = What You See Is What You Get

OK... So what?

WYSIWYG was a popular term to describe a feature of a Graphical User Interface (GUI) that mimicked what you'd see on paper. It was most popular when using word processors. It means that your text effects (like italic, bold, underline, etc.) were displayed that way on the monitor.

Other paper-like mimicking features included pagination, margins, sidebars, headers and footers, insets, graphics, and pictures, right there on the monitor, formatted just like it would be when printed. Significantly, having a GUI also enabled inclusion of clickable icons for launching your programs and accessing files.

It meant that you could produce and create a document on the screen and see exactly how it'll look when printed, but without printing. That saved paper and ink/toner (far fewer draft printouts) and made on-screen composition easier and faster. This may seem obvious today and maybe you've never even seen it the "old way", but back in the 80's (that's 40+ years ago y'all!), it was revolutionary and groundbreaking.

But to make that whole effect work, to fully mimic paper, software designers chose to use black text on a white background, just like it would appear on paper.

And that's how light mode was born. But we didn't call it "light mode" because what came before wasn't called dark mode. If anything, it was called text mode and graphical mode, although those were not universal terms.

And for the years, nay decades, that followed, light mode was just the way it was done.

That was Then and This is Now

Today, we use our computers and devices for way more than word processing. Heck, a lot of us probably aren't "word processing" at all. Yet nearly every website and app we use follows that same decades-old black-on-white theme.

But is that really the best way? I say it's not.

Illuminated white screens are blasting our eyes with light. It's not that it's harmful (being outside exposes you to far more light) but it's unnecessary and can be uncomfortable. It's like staring into a lamp aimed right at you. Excess light produces glare which can make it harder to focus on the black text. Dimming the screen helps but reduces contrast which, again, makes it harder to read (but for a different reason).

Using our devices at night is even worse. You certainly already know that reading a bright phone or tablet in a darkened room isn't very comfortable, causing you to squint your eyes. You've probably tried making the screen dimmer and found that making it too dim washes out the text making it harder to read (low contrast) and dulls the colors. Finding the right balance for night reading in light mode is difficult.

When we hear admonishments to not use screens at or near bedtime, it's mostly because excessive light, especially blue wavelengths, can wreck the circadian rhythm. Dark mode can help that to some degree. Granted, the stimulation from whatever you're doing also affects the circadian rhythm. But this is another example of how light mode can produce deleterious effects.

Peer Unto the Heavens

Go outside on a cloudless night and look up. Assuming you aren't in the fat middle of urbanity, you're going to see a lot of stars. Bright ones, medium ones, and barely visible ones. But you do see them.

Now imagine instead that it's full on daylight and the stars somehow all turned black. How many do you think you'd see, what with all the sunlight overpowering your eyes?

Back Inside Again

Let us imagine a screen full of black text, and maybe some pictures or graphics, on a white background, the way most webpages are displayed.

The average number of pixels used to render text on a screen is about 5% to 15% depending on typeface, size, weight, line spacing, etc. And that doesn't count the space outside the margins -- the sides of your browser screen that are always white with nothing on them. If you count that extra-marginal space, the percentage of text-rendering pixels falls even farther.

But for this example lets assume edge-to-edge text and a 10% midpoint for text pixel density. That means that 90% of the pixels on the screen are emitting (usually white) light so that, by contrast, black text (using 10% of the pixels) can be visible.

That bright light hitting your eyes can cause blooming which can interfere with comfortably detecting the dark pixels. To be fair, blooming can happen in dark mode, too. But because the overall brightness level is reduced in dark mode, the light load hitting your eyes is far less.

Text carries the intelligence of what you are trying to read. The non-text (usually white) light only exists as a contrast to allow the unlit pixels that form the text to be visible. The pixels of white light that aren't immediately adjacent to unlit/dark text-rendering pixels isn't contributing anything. It's just more light in your face.

But what if the actual text is what's lit up instead of everything else? Like what you are seeing right now, where the only light hitting your eyes is exactly that which is needed to perceive the text and nothing more. The space between a letter's typographical elements, between each letter, between the lines, and outside-the-margin sides of the browser are all dark. In dark mode, using our example, only 10% of the pixels are emitting light. That's far fewer, an order of magnitude less. It also significantly increases contrast, an important factor in making things readable.

And even setting aside all the facts I've stated above, sitting at a screen all day blasting you with bright light is fatiguing. The eyes can get really tired of that. There's a reason that old TV trope of police detectives questioning a suspect involves shining a desk lamp in their face.

Other Benefits

It's not just comfort in reading. Most modern phones are moving toward OLED (Organic Light Emitting Diode) screens. This means that each pixel emits its own light rather than having a backlight. To the extent that fewer pixels are emitting light (such as dark mode) that's less battery power being used. You could get an extra hour or two or three of battery life per charge. That makes sense. The screen is the single biggest power draw.

Dark Mode is finally getting some love. iPhone, most Android models, Windows, and Mac all offer dark mode to various degrees. But device dark mode doesn't automatically confer to the websites we visit or apps we use. Websites, like mine, have to specifically include dark mode for you to see it. The vast majority do not. Phone apps are a little better at honoring dark mode but not much. The developer must include that capability.

But there are browser add-ons that can render most websites in dark mode. They aren't perfect but they do work pretty well. And they usually include settings for tweaking dark mode rendering errors for each website to get optimum results.

One such add-on is called "Dark Reader", available for Firefox, Chrome, Edge, and other browsers. Dark Reader is free (though they accept donations) and it doesn't have ads. I love Dark Reader, use it extensively, and donated to their project. I experience dark mode almost exclusively now and my eyes are happier for it.

Do you want to see a real time dark/light mode comparison? Well, of course, you do.

Visit the website www.dpreview.com, a digital photography website rich with images that lets you switch between dark and light mode with a single click. After landing on the DPReview home page, look toward the top-right corner for "reading mode".

Click between light and dark and see for yourself, in real time. Which mode is easier to read? Which mode is more comfortable on your eyes? Which mode would you rather not stare at for many hours a day? Which mode just looks better especially when looking at all the nice pictures on something like DP Review?

Not everyone likes dark mode. Maybe because they haven't adequately seen it in action or given it enough of a chance. Or maybe they have a relatively uncommon eye condition that dark mode aggravates. Or maybe they just don't like the dramatic visual change.

I'll end with this: Light mode is a historical artifact intended to ease the way for former typists into the computer age, not a thoughtfully chosen standard. The real differentiators today -- readability, eye strain, subjective comfort, device context -- don’t break in light mode’s favor. Other than that conceit to paper's familiarity, light mode had -- and has -- nothing to recommend it. There's nothing inherently superior to light mode and, indeed, plenty wrong with it. It's stuck around due to institutional friction to an early standard. Not too unlike our U.S. customary system of measurement when metric is clearly, objectively superior in every way.

Give dark mode a proper run and see if you like it. I'm betting you will and I can help you with that.