Pixel

In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest part of an image you can see on a screen or in a picture. Pixels are like tiny building blocks that come together to make up photos, videos, and everything we see on computers and phones. They are arranged in a grid, and each one can show a different color or shade.

Each pixel can change its brightness or color. In color images, a pixel usually shows a mix of red, green, and blue, or sometimes cyan, magenta, yellow, and black. By combining these colors in different amounts, we can create almost any color you can imagine.

The idea of a pixel has been around for a long time, even before modern computers. The term "pixel" has been used in patents since 1911. On older computers, pixels were big and easy to see, which led to a special kind of art called pixel art. Today, screens have many tiny pixels, measured in megapixels, which means they can show very detailed and lifelike images.

Etymology

The word pixel comes from two parts: pix (a short way to say "pictures") and el (which means "element"). So, a pixel is like a tiny picture element. The idea of a picture element goes back a long way — even to the early days of television!

The word pixel was first used in writing in 1965 by a scientist named Frederic C. Billingsley. He worked with pictures sent back from space probes exploring the Moon and Mars. Before that, people had used other words to describe these tiny parts of pictures.

There’s also a fun filmmaking trick called pixilation, where actors pose for each frame of a stop-motion animation. This isn’t related to pixels in digital images, though!

Technical

A pixel is the smallest part of a digital picture. It can be found in many places, like printed pages, electronic signals, digital cameras, and display screens. Pixels are often called by other names such as pel, sample, byte, bit, dot, or spot, depending on where they are used.

The more pixels an image has, the closer it looks to the original picture. The number of pixels is called the resolution. For example, a camera might have three million pixels, called a three-megapixel camera. Displays can show images made of pixels arranged in rows and columns, like a 640 by 480 display, which has 307,200 pixels in total.

Pixels are usually arranged in a grid pattern. This makes it easy to process images on computers. However, some devices use different patterns. For example, LCD screens often have pixels split into red, green, and blue parts at slightly different places to improve how text looks. Most digital cameras use a special pattern called a Bayer filter, where each pixel’s color depends on its position in the grid.

The number of colors a pixel can show depends on how many bits are used for each pixel. With just 1 bit, a pixel can be either on or off. With more bits, more colors are possible. For example, 8 bits per pixel can show 256 colors, while 24 bits per pixel can show over 16 million colors.

Many screens and cameras cannot show all colors at the exact same spot. Instead, they use small areas for each color, called subpixels. For example, LCD screens often split each pixel into three subpixels for red, green, and blue. This helps create smoother and more detailed images.

Megapixel

A megapixel (MP) means one million pixels. We use this term to talk about how many pixels are in a photo, how many parts a camera sensor has, or how many parts a screen can show.

For example, a camera that can make a picture that is 2048 pixels wide and 1536 pixels tall (which makes 3,145,728 pixels total) is often called a "3.2 megapixel" or "3.4 megapixel" camera. This depends on whether we count just the working parts or all the parts of the sensor.

The number of pixels is sometimes called the "resolution" of a photo. We can find this number by multiplying how wide the sensor is in pixels by how tall it is in pixels.

Digital cameras use special chips to take pictures. These chips have many tiny parts that each catch light of one color — red, green, or blue. The camera then mixes information from these parts to make the full color picture. These tiny parts are called "pixels," even though each one only catches one color. So, a camera that makes an N-megapixel picture really only catches one-third of the color information itself — the rest is figured out by the camera. This can sometimes make some colors look less sharp.

DxO Labs created something called the Perceptual MegaPixel (P-MPix) to measure how sharp a camera’s pictures are when used with a certain lens. This tries to be more helpful for photographers than just the megapixel number the maker advertises. As of mid-2013, the Sigma 35 mm f/1.4 DG HSM lens on a Nikon D800 had the highest P-MPix score. In August 2019, Xiaomi made the Redmi Note 8 Pro, the world’s first smartphone with a 64 MP camera. Then, in December 2019, Samsung released the A71, which also had a 64 MP camera. Later in 2019, Xiaomi announced a phone camera with an even bigger 108 MP sensor.