A teleprompter is a valuable and versatile tool for any filmmaker or videographer using scripted content. Teleprompter technology is available for smartphones, for speakers’ podiums, and for more traditional DSLR cameras. Learn the science behind teleprompter beam splitter glass to understand how this technology makes your script easier to read.

What Is a Beam Splitter?

In layperson’s terms, a beam splitter is a specialized mirror with a coating that allows it to reflect and transmit light simultaneously. The glass splits the beam, or light source, when placed at the correct angle. This technology is also used in two-way mirrors that show a reflection on one side and allow people to see through the glass on the other side.

Beam Splitters in Teleprompter Technology

Beam splitters and two-way mirrors are made in a variety of transparency (T) and reflection (R) levels, depending on their intended use. For example, privacy glass for homes often has a coating with 70 percent reflection and 11 percent transparency (70R/11T).

Beam splitter glass for traditional teleprompters is often rated at or around 70R/30T. The strong reflection allows your on-screen talent to read the words clearly, and the relatively low transparency prevents ghost images and muddled text.

Beam Splitter Setup

If you’ve recently invested in a teleprompter for your DSLR camera, familiarize yourself with its components and practice placing the glass at the correct angle. A common setup for a teleprompter features a light source behind the prompter, with the prompter itself laid flat. Place the beam splitter glass at a 45-degree angle over the prompter.

The light source will shine through the glass and reflect the words onto the prompter. Because the glass is placed at an angle, your on-screen speaker will be able to read the text easily as they face the camera.

Good To Know:

The text on your teleprompter will be reversed in the mirrored glass of the beam splitter. Change the settings in the prompter to reverse the text so it will read properly in the mirror.

Acclimate yourself to your new teleprompter by learning about its beam splitter glass and the science behind why it works. Think of your beam splitter like a two-way mirror, and perfect its angle to improve your teleprompter’s visibility.