Join Date: Feb 2000
Location: Ontario, Canada
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Hot spotting & colour shift are usually mentioned in the same breath -- so I'll describe both.
Hot spotting: Avia has a test pattern for this. It basically means that the center of your screen is brighter than the edges. If you were to use a mirror as a screen you'd have the worst "hot spot" possible. Higher gain screens have more hot-spotting than lower gain screens. Most casual observers won't notice this effect even on the Draper M2500 screens which are about 2.3 gain. The degree of hot-spotting depends on how bright your projector is.
Colour shift: (forgive the spelling, I'm Canadian) This is an emphasis on blue on one side of the screen and red on the other. Corresponding directly to the 3 CRT tubes. If you are using a single lens projector you won't have this issue. The higher gain screens also show more colour shift in general. Even on my 1.3 gain screen I notice some colour shift. Careful calibration / setup can hide most of it -- but again, part of it is the nature of the technology.