What does the HD, or High Definition in an HD projector actually mean?  Well, 480 pixels PSI is the normal visual quality.  The lowest image resolution that can be called HD is 720 pixels PSI.

If the HD projector you are considering purchasing has a lower PSI than 720 pixels PSI then it is not really an HD projector and the image quality may well be disappointing.

In the terminology for HD quality there are also two other letters than you should pay attention to, the scanning type.  These can be i – interlaced, or p – progressive.  The progressive scanning type is generally considered to be of superior quality, therefore it is customary to think of 720p HD projectors being equivalent to a 1080i HD projector.

Although these terms appear technical, they are in fact just ways of describing certain features of the HD projector and should not be too concerning.