Understanding resolution
Digital photographs are made up of tiny dots called pixel. It is the smallest unit of a computer graphics. Generally a single pixel contents a single color code.
Image resolution
Image resolution is defined as the number of pixels displayed per unit of the printed area of an image. Generally, image resolution is measured in pixels per inch or PPI.
In computer graphics pixels are square in shape but, video pixels are rectangular shaped. That’s mean videos has different spatial sampling in the horizontal and vertical direction. A square pixel has a sample aspect ratio of 1:1
When printed, high resolution images produce more detail and smooth color transitions than low resolution images.
To determine the optimum image resolution, think about how you plan to use the image. If you preparing an image for online display, keep the resolution either 72 or 96 DPI (standard monitor resolution)
Device resolution
Device resolution is the number of pixels present per inch (dpi) this resolution is depend on the size of monitor and the settings. Most of the new monitors have a resolution of about 96 dpi or 72 dpi.
Print resolution
The printer resolution refers to the number of ink dots printed per inch (dpi). Most laser printers have a resolution of 600 dpi.
Screen frequency or line screen is the number of printer dots per inch used to print grey-scale images or color separations. It measured in line per inch or lpi
