# Master Projection Geometry
Installing a projector by eye can ruin the experience. Too close and the image is tiny; too far and you lose brightness. The key is the Throw Ratio, a number that precisely defines the relationship between distance and image size. TR × W Distance Formula
< 0.4 Ultra Short Throw
> 2.0 Long Throw
What is the Throw Ratio?
The ratio between the projection distance and the image width. A TR of 1.5 means you need 1.5m of distance per metre of screen width.
- TR < 1: Short Throw, ideal for small rooms
- TR 1–2: Standard for living rooms and meeting rooms
- TR > 2: Long Throw, for large auditoriums
Format and Aspect Ratio
The format determines image proportions. Using the wrong format creates black bars that waste screen area and reduce perceived brightness.
- 16:9 (1.78:1): HD/4K standard for cinema and series
- 21:9 (2.35:1): cinemascope format for home cinema
- 4:3 (1.33:1): for presentations and office projectors
# Professional Installation Tips
Lens Shift vs Keystone: If your projector has Lens Shift, always use it instead of digital Keystone. Keystone crops pixels and reduces effective resolution. A correct physical mounting eliminates the need for any correction.Ambient Light and Screen Gain
In rooms with ambient light, consider a high-gain screen (>1.0) to compensate for contrast loss. In dark rooms, a neutral (1.0) or negative-gain screen delivers better viewing angles and more uniform colours.
Installation Checklist
Note your projector's Throw Ratio before choosing the mounting location.
Check the maximum image size allowed by the available space.
Mount the projector centred vertically relative to the screen.
Avoid digital Keystone: use Lens Shift or adjust the physical position.
Ensure no direct light sources are pointing at the screen.