Pixel and Resolution in Computer Graphics


Each screen point is referred to as Pixel or Pel. A pixel may be defined as the smallest size object or colour spot that can be displayed on a monitor. An image displayed on the monitor is made up of thousands of these small pixels.

The closely spaced pixels divide the image area into a compact and uniform two-dimensional grid of pixel lines and columns. Each pixel has a particular colour and brightness value. Though the size of a pixel depends mostly on the size of the electron beam within the CRT, they are too fine and close to each other to be perceptible by the human eye.

Resolution in Computer Graphics:

The number of horizontal and vertical pixels on a display screen is called Resolution.

Types of Resolution:

In Computer Graphics, there are two types of resolution exists:
1. Image Resolution
2. Screen Resolution

Image Resolution: It refers to the pixel spacing the distance from one pixel to the next pixel. In other words, the resolution of an image is the total number of pixels along with the entire height and width of the image.

Example: A full-screen image with a resolution of 800×600 dpi means that there are 800 columns of dot pixels per inch and each column comprises 600 dot pixels per inch.
A total of 800×600 = 48000 dot pixels in sq. inches image area.

Screen Resolution: Screen resolution is the number of pixels on a screen, both horizontally and vertically. So, a screen that has a resolution of 3840 x 2160 (It is also known as 4k UHD), it can display 2160 pixels vertically, and 3840 pixels horizontally.

Aspect Ratio:

The Aspect Ratio is the ratio of the number of X pixels to the number of Y pixels. The standard aspect ratio for PCs is 4:3. Some common resolutions, the respective number of pixels and the standard aspect ratio are given below:

ResolutionNumber of PixelsAspect Ratio