A Practical Guide to Stage Lighting, 2nd Edition

The Load-In and Focus Packet

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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 100’s, 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 100’s 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