Professional Lighting & Production - Summer 2019 | Page 30

Video walls support
Jack White on
the 2018 Boarding
House Reach Tour
30 PL&P
BOOST
YOUR VIDEO VOCABULARY
An Updated Video Primer for Lighting Pros
By Andrew King
We
brought you our first
video primer five
years ago, and in the
context of a fluid and fast-evolving
technological discipline like video for
live events, that’s basically an eternity.
Then, like now, video was becom-
ing increasingly integral to designs
for concerts, theatrical productions,
and a myriad of other applications,
making close and seamless collabo-
ration between visual disciplines vital
to success.
What’s more, the trend of tech-
nology enabling productions to do
more with increasingly shrinking re-
sources has often resulted in lighting
professionals being tasked with the
design, management, and operation
of video systems of varying degrees of
complexity.
In light of these ongoing trends,
we present our updated glossary of
video terms and concepts to facilitate
your interactions and collaborations
with these technologies and techni-
cians, all with the goal of delivering
better shows for everyone in front of,
on, and behind the stage.
FUNDAMENTALS
Here are some basic video terms relevant
to virtually any live production, regardless
of whether you’re using projection, video
panels, or smaller displays.
ANSI
The American National Standards Institute over-
sees the use of many guidelines and measure-
ments related to video.
Aspect Ratio
Denotes the shape and dimensions of your
image. Generally speaking, there are two tradi-
tional and widely used ratios: 4:3 (standard TV)
and 16:9 (widescreen TV).
Brightness
Overall light output from an image. While a
brightness control can make an image brighter,
it is best used to better define the black level of
the image.
Contrast Ratio
The ratio of the luminance of the brightest
colour (white) and darkest colour (black) that a
system is capable of producing. The larger the
contrast ratio, the greater the ability of a video
device to show subtle colour details and tolerate
ambient room light. There are two generally-
accepted standards in the industry to measure
contrast ratio:
• Full On/Off Contrast measures the ratio
of the light output of an all-white image
(full on) and the light output of an all-black
image (full off ).
• ANSI Contrast is measured with a pattern
of 16 alternating black and white rectan-
gles. The average light output from the
white rectangles is divided by the average
light output of the black rectangles to
determine the ANSI contrast ratio.
Tip: When comparing the contrast ratio of
different video devices, be sure that you’re
comparing the same type of contrast. Full On/
Off contrast will always be a larger figure than
ANSI contrast for the same device.
Dolly
A piece of equipment that allows for a camera
to roll or slide smoothly when it’s recording.
Format
Refers to the type of video you are shooting
as expressed by vertical pixels and frame rate,
usually in terms pertaining to resolution such as:
1080/60i or 720/24p. It may also be more gen-
erally referred to as standard definition (SD) or
high definition (HD) as determined by the lines
of vertical resolution. See also: Resolution.