Low resolution on my computer/tv screen?

What is the difference between a TV and computer screen's resolution?

• Answer:

  Television screens are typically viewed from a distance, so they are built larger than your average computer screen. From a few meters away, the pixels that make up the image can be much larger than on a computer screen, and you still achieve a clear, sharp image with something like 1920 x 1080 (Full HD) pixels. Step closer to a large TV, however, and you'll start to see the individual square picture elements. Computer screens are used for viewing small detail, like text, from a close distance. To make things look sharp, the screen needs smaller pixels, packed together more densely. A contemporary 27" iMac is considerably smaller than current +40" TVs, but the pixel count goes well beyond Full HD at 2560 x 1440. The display resolution of various pixel based devices is expressed as PPI (pixels per inch). The higher the number, the sharper the image. But as viewing distance is a factor, it's not a straight forward quality measure. Wikipedia has a great page listing the PPI of various devices, at http://en.wikipedia.org/wiki/List_of_displays_by_pixel_density Here are some examples: - iPhone 4 has 640x960 pixels on 3.5" screen, resulting in an impressive 326 PPI. It is typically viewed from less than 50cm away. - An 11" MacBook Air has 1366 x 768 pixels on a 11.6" screen, resulting in 135 PPI. Text rendering isn't as clean as on the iPhone, but the viewing distance helps remedy it a bit. - A 42" Full HD television with 1920 x 1080 pixels gets away with only 52 PPI. Best viewed from the couch a few meters away :)