Pixels. The word can mean different things. If you’re a marketer, it means a little bit of code in your page to help you track things. You might vaguely remember there was a 2015 film of that name. It bombed hard, although I liked it.

In most cases, though, talking about pixels means talking about the little dots of light that make up the words you’re reading right now. Pixels, in case you’re unaware, is a word meaning “picture elements,” and each pixel is a single bit of color made of red, green and blue light in varying proportions which, when combined by the millions, give you a photo-realistic image.

Inventor of the pixel

The photo at left is Russell Kirsch, who invented the idea of the pixel in 1957. The photo at right is the first digital image, and the first to use pixels. It’s worth noting that Mr. Kirsch died this year, with little fanfare. His photo lives on, and so presumably does its subject, Mr. Kirsch’s son. It was named one of Life’s 100 most influential photos, because it was the first to be seen on a computer screen.

The story of pixels is the story of how we use computers

Computers were around before images. I mean, obviously. And, images didn’t dominate the world of computers until the early 1980s. But, once people started interacting with their devices using mice, photos, and eventually touch and voice, the world of computers was opened up to everyone.

That’s what makes the pixel so important. It’s almost like the atom of the computer. It’s the smallest bit of information you can have that’s actually useful.

How many pixels do you need?

For decades, it was thought that not only could you really not get more than about 96 pixels to the inch, you wouldn’t need to. That changed oh, not long ago, when the first hi-DPI panels were put into smartphones. We called them “retina” displays, but what we really meant was something of at least 200 pixels to the inch. That’s so small that the pixels themselves are largely impossible to tell apart without a magnifying glass. It’s closer to the level of detail that we actually use to perceive the world, which depending on a lot of factors ranges from about 180 to 360 pixels to the inch.

You see, there’s a native resolution to your eyes as well; the color receptors in them come in finite rows and columns just like a TV’s display. So while you can brag about the quality of a 450ppi (pixels per inch) display, its value is largely lost on the average human.

Hi-DPI panels

Hi-DPI panels make the world more realistic whether we’re talking about smartphone displays or 4K monitors, and they tend to help us forget that we’re not looking at reality. We’re just looking at one computer’s perception of it. Increasingly though, that’s all we care about. Previous generations remember their past in black-and-white, sepia-tone, or in the blue-starved, blurry images from faded Kodacolor prints.  Tomorrow’s adults will remember their childhoods in the saturated, bright jewel tones achievable from hi-DPI display panels.

Recently, the latest iPhones doubled their pixel density. It’s not as big a jump as it sounds, because of the way that grids work. If the number of pixels had doubled horizontally and doubled vertically, that would be four times the pixels, not two. But does it matter? As I said it’s practically impossible to see pixels on most modern phones.

Getting philosophical

Which really makes you think about how display technology does more than represent reality, it becomes reality. Of course none of us grew up in black-and-white; none of us had childhoods that reflected the muddiness of Polaroid pictures either. But somehow the past as we see it becomes intertwined with the photos we use to view it, and if your childhood pictures are brown or pale green from age, or if your high-school yearbook shows black-and-white images of you and your lifelong buddies, your memories form around that and it gets every harder to realize that the world of forty, fifty, or more years ago looked just as it does today, putting aside styles in clothing and furniture. We look at the past differently than we do the present. I don’t know if that will be true in 20 years. Pixels don’t age like physical photographs, after all.

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.