Some television standards show images at 50/60 fps. Action games are meant to be played at 70-80 fps. But, if our eyes maintain the image only for like 1/6th of a second.. why is that we can detect flutter even at 24 fps in some cases [sometimes flutter is visible even at 30 fps or something]. also, what is the resolution power of our eye. This question is related to the maximum dpi we need achieve. There has to be some limit of the eye, for example a measurement in length. If two particles of smaller sizes are kept side to side, the eye cannot detect the difference between the two particles. Like, if the limit is 'x' dpi, then if i keep two pixels at a resolution of more than 'x' dpi, the eye cannot determine the difference.