What Is Pixel Density and How Does It Relate to Photography?

Pixel density is a measure of the number of pixels contained in measured area. Often measured in PPI ‘Pixels per Inch’ or DPI ‘Dots per Inch’ pixel density in photography is a measurement of an image or sensor’s resolution and is dependant on the size of the pixels being measured. Pixel density is especially useful when printing an image. If we were to rely on the true image resolution, for example 640 x 480 pixels, but printed two images of different sizes, the true resolution of 640 x 480 would remain the same but the pixel density of the larger image would decrease.