Resolution is a measurement of the number of pixels (picture elements or individual color dots) that can be included in a display or camera sensor. In fact, resolution describes the sharpness or clarity of an image or picture. It is expressed in the number of pixels that can be displayed horizontally and vertically.
Represented resolutions: monitor, printer, and audio
In most monitors and digital images, resolution is expressed as PPI, which refers to the number of pixels that can be displayed on a one-inch screen or monitor. A high PPI means more pixels per inch, resulting in higher resolution and sharper images. If an image has a low PPI, it will result in a blurry, blocky, or pixelated image that is difficult to view and interpret.
For printers, resolution is usually expressed in dots per inch (DPI), which refers to the number of dots produced in the printer's output. The smaller and finer the dots, the higher the DPI and the clearer the printout.
Consumer-grade laser printers or inkjet printers have a much lower DPI than professional-grade printers. That's why the former isn't suitable for printing on certain media that require high-quality output, such as photos.
The term "resolution" is also used for digital audio. It refers to the number of bits or bit depth in an audio sample or digital recording. Like PPI and DPI, higher bit depth is directly related to output quality.
Resolution type
There are two types of resolution:
Image resolution: Image resolution refers to the density of pixels in the image, expressed by PPI. This should not be confused with image size, which is expressed as a measure of the number of rows and columns of pixels the image contains, such as 640x480.
Screen Resolution: Display resolution or screen resolution means how many pixels there are in a monitor or the entire screen. The maximum resolution of a given display is determined by its physical ability to focus light. For example, a 15-inch 640x480 monitor will display approximately 50 dots per inch. Smaller displays will have higher PPI.
Generally speaking, screen resolution is the number of pixels that can be displayed horizontally and vertically on the screen. So a screen with a resolution of 1920x1080 (1080p or Full HD) can display 1,920 pixels horizontally and 1,080 pixels vertically.
In addition to the maximum resolution, the monitor can support a variety of lower resolutions. For example, a 1280x1023 monitor can also support 1024x768, 800x600, and 640x480 resolutions.
While applying maximum resolution to a larger monitor may result in a sharper display, it won't necessarily result in the same quality when used on a smaller screen. Icons and text may appear too small on screens configured with a higher resolution than they should accommodate. On the other hand, if the screen resolution is too low, it usually results in poor image quality.
Screen size and resolution
The terms screen resolution and screen size are sometimes used interchangeably. However, they are not the same. Screen resolution refers to the number and density of pixels, while screen size refers to the physical size of the screen. The latter is usually measured diagonally in inches, from one corner of the screen to the other.
Two displays with the same resolution can have different physical dimensions, which is why pixel density, expressed in PPI, is an important factor. The sharpness of the image is affected by screen size and not having enough pixels.
Likewise, two monitors with the same screen size can have different resolutions. A screen with a higher pixel count and a higher PPI will have a better resolution than a screen of the same size with a lower pixel count.
Image quality will also suffer if two screens have the same resolution but different sizes. At the same resolution, a smaller monitor will have a higher PPI and display a clearer, more detailed image than a larger monitor.