bobology newsletter: What is a Pixel?

Pixels are tiny dots. No, we're not talking the candy kind. Pixels are those tiny dots that create what you see on computer displays (LCDs or flat screens) and tube monitors (CRT or desktop computers and digital TVs). Pixel means PICture ELement.

You can't see pixels because they're very small, which is good because you want to see the whole image and not those dots that make up the image (or pixilated images). Pixilated images are possible to see with your computer monitor screen set to a low resolution, such as 620x460, which means the product of width times height, for a total of 285,200 pixels, which may seem like a lot, but computer screens need more resolution to be clear and sharp. 

Image Resolution

In a general sense, the more pixels used to represent an image equals a sharper image. The image resolution is measured by PPI, or pixels per inch. Resolution is also expressed in pairs of numbers such as 640 x 480 (width x length). A MacBook Pro 15-inch monitor, for example, has the PPI of 110 PPI and a 1440x900 resolution.

A basic digital camera has a resolution capacity of between 2 million pixels (MP) to 5 MP and the more pixels the better. A 4MP camera makes really sharp prints that are 4”x6” and pretty nice larger prints at 5”x7”.

Pixel colors

Every single tiny pixel contains three color channels of red, green, and blue. Each color in this scheme is represented by an 8-bit number, or a byte, with the color of each pixel defined by three color bytes. These three colors combine in over 16 million color combinations to form the many different hues and shades you see on your screen and camera.

For example, if an image contains the color depth of 8-bits, it will seem grainy or spotted. A 32-bit color image looks much more smooth and realistic.

Pixels Are Everywhere

It helps to know how pixels work because everything is digital these days, from your TV to your computer screen to your camera – even to the images you see displayed on your cell phone. You don't have to be a technological wizard to understand the basics so that you can get the best resolution for what you need and like.