Technical realisation


A colour synthesizer patch

Colour keyboard

One of the light elements

The instrument

In order to realise the colour part of Prometheus according to these artistic principles a totally new light instrument had to be developed. It consists of four essential elements:
- the installation of lighting equipment and projection screens,
- the filtering needed to produce the colours,
- the colour synthesizer that feeds information to the lighting equipment,
- the colour keyboard that puts this information under player control.
The development of this light instrument was done in stages. A brief description of the various elements follows in the order of their elaboration.

Colour filtering
The colours are produced by means of lamp triplets supplied with high-quality dichroic filters in the primary colours red, green and blue. The quality of dichroic colours is by far superior to those produced by plastic filters. Since any colour can be made by means of correctly scaled mixes of the primary colours, one is not limited to the basic colours of the Skryabin scale. This way there is a possibility to modulate and shade to create more variety in the coloured image. Moreover, the amount of lamps necessary to give a certain intensity of light at any spot is decreased radically as one would otherwise need at least 12 lamps per point. The resulting colours can also be easily corrected to fit the situation in the hall. 

Colour synthesizer
As mentioned above, common light control techniques were found to be unsuitable to this particular project. Instead, a colour synthesizer was developed in the modular technique used for electronic music synthesizers in the sixties. To explore all possibilities of making colours move, transform and breathe, a spirit of freedom was indispensable. 
It soon proved impractical to use a recorded performance to develop the colour part. Therefore, a development model was conceived. This model uses a MIDI sequencer file to simulate the orchestra as well as the luce player, with sound modules rendering the music and the colour synthesizer controlling the light sources, both receiving MIDI signals from the computer. The work developed around a 1:10 scale model using 12V halogen lights and brought about a thoroughly worked-out concept for the performance in a large hall. In fact, the model is a true replica of the situation in a concert hall, with five foreground screens and background projection; only, the matrix of colour points is 5X4 as opposed to 10X8 in the full scale set-up.

Colour keyboard
A common MIDI keyboard has been used during the development. However, a special light keyboard has been built to meet the requirements of this particular set-up, constructed around a high-quality keyboard with hammer mechanics and completed with a certain number of analogue controllers as well as pedals. Although an initial control computer is needed for making the necessary on-the-spot changes to fit the hall, during the actual performance everything is controlled from the keyboard, feeding MIDI information to the synthesizer. This set-up, once programmed, constitutes a stand-alone system that needs no other equipment to control the show.
The process of composing the colour part was vital to the artistic result. The part to be played on the colour keyboard was developed using the original luce part as a starting point. The two voices, however, being noted within one octave (the range of Rimington's instrument) had to be transposed to different octaves. The sequencer file was the medium in which the composition took place, first providing the necessary information for the desired visual effect, then taking into account the practicality of the part. Actually, all 8 octaves of a full-scale keyboard are used for different purposes, and changes had to be made to ensure that the part was playable.
The resulting file was then converted into the light score. In this way, the practical score reflects the information accumulated during the compositional process by means of notes and symbols legible for any trained orchestra musician, preferably a pianist or an organist. The player doesn't have to keep the notes that control the colours, but has his hands free to play notes in other octaves controlling shapes, gestures and other events, or to activate one of the analogue controllers. The latter are two wheels and two ranges of aftertouch pressure (one for each hand) used for more expressive functions as colour bend or vibrato depth.
One player is sufficient to perform the part although he will have to rehearse for some time to acquire the mastering of the special technique. These rehearsals, however, can be done with the scale model.

Light technician Jan Holsbergen adjusting the lamps

In the back of the hall, behind the orchestra, five giant columns rise up to the ceiling. In fact, these are projection screens of translucent PVC, approximately 2 by 10 meters each. Each screen is divided into 8 vertical and 2 horizontal segments, which gives a matrix of 10X8=80 light points. With three lamps for each point this results in a total of 240 lamps. This amount of light sources ensures that the lamps be kept relatively small, which is important in connection with response time. As commercial spots were found unsuitable, however, special spots had to be developed. Aluminium housings containing a 650W PAR-lamp and a dichroic filter were constructed and mounted in groups of 12 on aluminium frames that house dimmers controlled serially from the colour synthesizer. These frames hang in 5 rows of 4 behind the front screens and are fitted with frost filters to smoothen the transitions between matrix points.
Behind, a second level of projection is provided by means of a horizon screen. Normal 500W halogen lamps are used to illuminate this screen, again equipped with dicroic filters. Six of these on each frame, or a total of 120, are shining backwards. 
In addition, a row of spotlights for the choir is installed with blue filters.
Thanks to the modular construction, the equipment is relatively easy to transport and to mount. It is developed in view of mobility permitting performances anywhere in the world. 

Requirements for a performance
After the premiere the project is offered for performance throughout the world. The stand-alone character of the installation makes it suitable for any hall that can offer enough space and mounting facilities. The Luce Foundation offers a package for one or several consecutive performances that includes
- the colour keyboard performer,
- the production team,
- the special lighting equipment and the projection screens,
- the light score,
- the colour keyboard and colour synthesizer,
- the rental of all other equipment and a crew.

Music stand lighting and electric power have to be provided by the hall. Details on the power requirements and minimum mounting facilities can be given upon request.
The final tests for a given performance have to be done in the hall itself when everything has been installed. They include adjustment of the colours to the hall (every hall has its own "light temperature"), running a number of test patterns to check the quality of the lighting setup, and making settings for maximum allowable power. To this purpose, one extra rehearsal with orchestra and choir will be required in addition to the dress rehearsal.
One day is needed for rigging and four hours for derigging.

Visual presentation of the project can be given either with the scale model in our workshop in Amsterdam or by means of a videotape/CD-ROM presentation.

Stichting LUCE
Waldecklaan 19
NL-1405 CP Bussum, Netherlands
tel/fax +31-35-69 35 381