98 TECH ADVISOR • MAY 2020
FEATURE
Pixel density
Pixel density, or the number of pixels packed into one
square inch of screen (measured in pixels per inch or
ppi), is the most important factor to consider. A 15.6in
laptop screen with a 1,920x1,080 resolution has a pixel
density of 141.21ppi, while a 32in HDTV screen with the
same resolution has a significantly lower pixel density of
68.84ppi. The lower the pixel density, the less clear and
detailed the image becomes.
But the importance of pixel density decreases with
viewing distance. The further you sit from a screen, the
lower the pixel density need to be for you to have a
comfortable viewing experience. You won’t have any
problems looking at a 15.6in/141.21ppi screen from
two feet away, but you will find it much harder to view
a 32in/68.84ppi screen from the same distance. This is
why a ‘Retina’ screen on the iPhone has a pixel density
of 326ppi, but a ‘Retina’ screen on the MacBook Pro
has a pixel density of just 226ppi.
A normal user sits between two and three feet away
from a desktop monitor. To comfortably view a monitor
atthisdistance,youshouldaimfor80ppiorhigher.
Thismeans that for 1,920x1,080 (1080p) resolution,
your screen should be no larger than 27.5 inches
diagonally,andfor4Ksets,you’llwanttomaxoutat
55 inches,likethe TCL DP628 4K UHD TV (£479 from
fave.co/3by4w2J). We reviewed it, and it’s solid.
Important: ‘4K’ is not a market standard. A 4K HDTV
can mean 4x 720p (3,840x2,160 resolution) or 4x 1080p
(4,096x2,160 resolution). Most models use 3,840x2,160,
but you should check the exact specs of your model to
determine pixel density.
