videocompany.ch :: glossary

The 4:3 aspect ratio given for old monitors has been largely replaced by the 16:9 widescreen TV format. SD images in 4:3 need to be adjusted for playback on 16:9 projectors or screens, which also applies vice versa. Otherwise the images will be distorted during playback.

Passive speakers require an additional amplifier, active ones have an amplifier built in.

(American National Standard Institute) is the term for the light output of projectors. But more ANSI lumens don’t automatically mean you get a better picture. For most applications in museums and galleries, 3000–5000 ANSI lumens are typically sufficient.

If the room is completely blacked out, fewer may be enough.

A projection is possible as a front projection (the beam is projected in the line of sight of the viewer) or as a rear projection (the beam is projected onto the screen from behind). With a rear projection, the beam is “hidden” and not visible, hence there are no shadows on the image when the viewer is close to the picture. The drawback is that you may have a “hot spot” – the projection lamp can be seen as an over-lit point in the image.

Compact Flash Card/Secure Digital Memory Card

Memory cards for media players instead of DVDs or tapes for images in SD and HD resolution.

DVDs are suitable for playback of SD images but not for high-definition images. That’s what BluRay discs are for.

Usually a compressed version of the work to be displayed, e.g., on DVD, BluRay, CF or SD card.

Flat screens are typically in 16:9 aspect ratio; CRT monitors are usually in 4:3. Playback of HD in full resolution is not possible on a CRT monitor.

Standard Definition – a collective term for the “old” video and TV standards, before the introduction of HD television. SD video has lower resolution than HD video.

High Definition – term for the recording and playback of high resolution images in numerous variations.

DLP projectors have a deep, rich black, but are generally darker than LCD projectors. The image from a DLP beam appears about 20% darker than an LCD beam at the same lumen level.

Linear Tape Open, LTO for short, is a specification for tapes and the corresponding tape drives. All the works we compress (exhibition copies) are backed up on our LTO system. This way, individual works can be reordered without having to be compressed again.

In general, when a work is sold, a master tape (archive master), an exhibition copy and a certificate are presented to the buyer. From the master tape, the buyer can later record the work onto contemporary playback formats. The master tape contains the video in uncompressed form and is extremely durable and long-lasting.

Since most projectors usually come with a zoom lens, a range is stated for the projection ratio. So with a projection distance of 6 meters, a zoom lens with the projection settings 1.8:1–2.3:1 leads to an image with a minimum width of 2.61 meters and a maximum width of 3.33 meters.

As a very simple rule of thumb: the desired image width times two is the distance from the beam to the projection screen.