The Load-In and Focus Packet
237
Blackout Cues
Some light boards don’t automatically display a
cue list on the monitor. If a cue contains no chan-
nel intensity information, it may take moments to
determine if the cue is a blackout, or if errant pro-
gramming has taken place and channel intensity
information lost.
One work-around for this dilemma is to desig-
nate a block of unassigned channels as ghost black-
out channels to identify an “empty cue.” In the
Hokey hookup, channels 139 and 140, contain-
ing no dimmer assignments, have been designated
as ghost blackout channels. They are activated to a
unique level only in cues that are black on stage. In
the Hokey memories, if channels 139 and 140 are
displayed at an intensity of 11% (a unique level),
then that memory is a blackout cue. Any channel
intensities other than time stamp channels are sus-
pect, and should be checked.
Shelley’s
Note s
Shelley’s Notes:
Key Memory Numbers
This is every lighting designer’s nightmare scenario: the
cues for a production are contained on several disks
and a disk containing memories for some portion of the
show have been loaded into the computer light board’s
RAM; the disk has been removed, and then the board
operator disappears. The lighting designer is left staring
at the computer monitor. Which act is loaded into the
board? Is this the right version of the act? Which disk
was loaded into the board?
Every lighting designer has been there. Pre-
programming disks with key memory numbers,
how ever, provides a structure that identifies which
memories are currently loaded into the lighting con-
sole. The memories “carry” a unique identity by
numeric sequences in their ghost channels.
David K. H. Elliott introduced me to the concept
of disk management and key memory numbers when
he was the resident lighting designer at American
Ballet Theatre. At that time, ABT produced an active
repertory of 20 repertory (or one-act) and five full-
length ballets that would change on a yearly basis.
Although the company traveled with its own lighting
package and a computer console controlling 72 dim-
mers, the local house light board was used as well to
control FOH instruments and striplights.
At that time, disk storage was limited to floppy
disk. Not only was it impossible for all of the mem-
ories to fit onto a single computer disk, the size of
the repertory was so large that disks were changed
at each intermission. Using David’s method, how-
ever, it was still possible to view the monitor of either
lighting console to confirm that the proper memories
were loaded for the correct ballet. This was accom-
plished using ghost channels and David’s system.
Each repertory ballet, or act of a full-length bal-
let, typically had no more than 100 cues. Based on
that assumption, the cues had been allocated into
blocks of 100’s. Each ballet started with a different
series of 100’s, so a disk contained nine sets of cues
for nine different repertory ballets. The 100 series of
cues were for the ballet titled Murder, the 200 series
of cues were for the ballet called Requiem, and so on.
There were a total of eight show disks in the ABT
repertory ballet library, which, multiplied by the nine
ballets on each disk, resulted in a total of 72 ballets.
That being the case, although every ballet had its
own block of cues on its own disk, by looking at the
computer screen alone, it would still be impossible to
tell which disk had been loaded. Granted, the screen
might display light cues starting in the 100s, but unless
the board operator was present to confirm which disk
had been loaded, it might be Murder, or it might be the
100 series of cues from another disk.
To eliminate that confusion, David had created a
labeling system that assigned a unique four-digit num-
ber to each repertory ballet or full-length act. This four-
digit key memory number was split between the first
and the final three digits. The first digit was the ghost
label channel identifying the number of the disk, and
the next three digits identified the block of 100s cues
on that disk. The key memory number for Murder was
7100, meaning that on Repertory Disk 7, all of the cues
in the 100’s belonged to Murder.
At that point, the highest channel number used in
the ABT hookup was 72. Since the screen displayed
100 channels, channel 100 was assigned as the ghost
channel labeling the disk number. The floppy disk con-
taining Murder along with nine other rep ballets was
labeled Disk 7. When that disk was loaded into the
light board, no matter which ballet was chosen, chan-
nel 100 had a recorded intensity of 07%. Therefore,
if the computer monitor showed that memory 101
was the next cue and that channel 100 was at 07%,
the combination of the numbers identified the mem-
ory and the disk that had been loaded into RAM. The
board had to be loaded for Murder.
System Size
When most computer light boards are turned on so
that no information is contained in their memory, the
system size is reset to default values. The system size
refers to the number of dimmers that the board will
recognize and the number of channels that appear on
the monitor screen. On modern moderate consoles,
the number of dimmers is often a single universe of

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