Pixel density

Pixel density is the number of pixels per unit length or area in an image or display. It describes spatial sampling or display detail, commonly measured in pixels per inch.

Pixel: A pixel is a discrete picture element in a digital image or display. Pixel density counts these picture elements across a specified distance or area.
Pixel pitch: Pixel pitch is the physical distance between corresponding points on neighboring pixels. It measures spacing directly, the inverse of linear pixel density.
High-density display: A high-density display packs many pixels into a small physical area. It uses increased pixel density to make screen content appear finer.
Megapixel: A megapixel is one million pixels, commonly used to state a camera sensor’s or image’s total pixel count. Total pixel count does not specify the physical area those pixels cover.
Visual acuity: Visual acuity is the ability to distinguish fine spatial detail, often measured with a standardized eye chart. It helps explain when individual display pixels become indistinguishable.
Pixels per inch: Pixels per inch is a unit expressing the number of pixels along one inch. It is the most common linear measure of display pixel density.
Dots per inch: Dots per inch measures the number of printed ink or toner dots per inch. Print discussions often use it interchangeably with pixels per inch, despite measuring different things.
Responsive web design: Responsive web design adapts a website’s layout and assets to different devices and screen sizes. Web graphics often use density-aware assets to remain sharp across screens.
Screen size: Screen size is the physical diagonal measurement of a display’s visible area. The same pixel dimensions yield different densities on screens of different sizes.
Aliasing: Aliasing is distortion caused when sampled data cannot faithfully represent high-frequency detail. Insufficient pixel density can make fine patterns appear jagged or misleading.

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