1. Introduction

People often need to communicate effectively with an audience. They may do this because they want to:

- Show the latest status of a project or event
- Provide new information
- Seek to make a point
- Lay out a plan

And many other reasons.

Perhaps the simplest method is to stand up and speak directly to the audience. This is fine for very short announcements, but it is far less effective when trying to show more detailed or complex material.

This is why presentation technology was developed. It allowed more complex or detailed information to be conveyed in an interesting, digestible, and effective manner.

Until the advent of laptops, by far the most common technology was the overhead projector and the use of acetate slides. Then computers, laptops and presentation software came along that gradually replaced this technology.

This mini-web explains the original OHP technology and compares it to the more popular computer / projector method