This video glossary covers the terminology and defines the meaning of common video terms related to cameras, codecs, lighting, film set lingo, post-production workflows, and everything else you ever wanted to know about film and video production.
You might be familiar with High Definition Media Interface connectors, otherwise known as HDMI cables, from your home TV and computer electronics. If not, HDMI refers to a type of connection plug that acts as a standard for connecting TVs to computers and vice versa. HDMI is good for carrying both high definition audio and video between two sources.
High key lighting refers to a style of lighting where you put the source of your lighting behind and high above your subject to give them both a backlit glow and a softening look. This creates the effect of softening any harsh features, like removing blemishes or shadows that might appear on a face in a different type of light formation.
HMI lights are powerful lights that produce a large amount of light. HMI stands for Hydrargyrum Medium-arc Iodide, which means they use pressurized mercury vapor inside an arc lamp, which both runs more efficiently and more cool than tungsten light sources.
HMIs are used most often to emulate daylight, both because of their color temperature and light output. For example, if you are trying to shoot a scene night for day (meaning filming a daytime scene at night) you would likely use a large HMI as a source to bounce light off of to create the illusion of daylight.
HMIs are powered through ballasts, an electronic (or simply magnetic) device that regulates the arc.