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P
PATCHING
- To cross-connect lighting circuits around the stage area to a chosen dimmer. Connecting lanterns to dimmers.
- Using a cross-connect panel which enables any stage lighting channels to the control desk to control any dimmer or group of dimmers. Some large lighting boards have the facility for soft patching - a totally electronic way of patching. Some Rock Desks have a pin patch which allows groups of dimmers to be allocated to a particular control channel. Also applies to routing of sound signals.
PATTERN NUMBER
Many older Strand lanterns are identified by their Patt. number (eg Patt.23 is a 500W profile). The numbers bear no direct relation to their size or type (although lanterns of a similar design may have similar Pattern numbers.)
PC
Originally short for plano-convex - the basic lans shape of many lanterns / projectors. Now short for Prism- or Pebble-convex: a type of lens with a pebbled flat surface which gives a slightly harder edge than a Fresnel, but not as hard as a Profile. PC refers to a lantern with a PC lens.
PEAK DEMAND
A utility customer's maximum load. For purposes of calculating utility cost, peak demand is generally based on the maximum monthly demand, where demand is measured as an average over a time interval, usually 15 or 30 minutes.
PEPPER's GHOST
Trick used to make a ghost appear on stage next to an actor. A sheet of glass is hung across the front of the stage so that the image of an actor standing in the orchestra pit appears to float on stage. First shown at the Royal Polytechnic Institution in London by J.H.Pepper on Christmas Eve, 1862. Following many subsequent events, Charles Dickens used it during readings of The Haunted Man. Several plays were written specially to use the effect around 1863, but the long-term future of the effect was limited by the fact that the ghost couldn't speak. Peppers Ghost is now used to great effect in smaller scale applications like the Haunted Mansion in Disney theme parks.
PERCENT
Dimmer levels are expressed as a percentage of the supply voltage. (100% = 230 - 240 Volts.)
PERCHES
Lighting positions (often on platforms) at each side of the stage, immediately behind the proscenium. Some theaters use the term for vertical boom positions in front of the proscenium in the house.
PHASES
Electricity is generated and supplied to large installations as three separate supplies, known as phases.
In the UK, the three supplies are color-coded to ease identification. Each of the Red, Yellow and Blue phases are supplied down one cable to the building, but effectively give three separate supplies. Because there is a potential difference (voltage) of 415 volts between any two phases and earth/ground, care must be taken that pieces of equipment powered by different phases are not capable of being touched at the same time in case of a fault.
PHOENIX
A family of medium to large computerized lighting consoles manufactured by ADB. The desks use ISIS software running on an external PC-based processing unit which allows advanced networking possibilities.
PHOSPHORESCENCE
The property of some materials that can store light energy and glow in the dark.
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