THE WORLD OF REFLECTED LIGHT, PART 2: THE CONCEPT OF DEDOLIGHT LIGHTING INSTRUMENTS

THE WORLD OF REFLECTED LIGHT, PART 2: THE CONCEPT OF DEDOLIGHT LIGHTING INSTRUMENTS

Watch 13 part series at: https://tinyurl.com/3u8vpb7h

The biggest instrument we provide at the moment is the parabolic PARALLEL BEAMLIGHT PB70.

Such parallel beam lights are not new, they have existed in different versions in the professional lighting and entertainment industry, and for special effects.

Search lights have been used to locate flying bombers before the days of radar. For effect, especially at nighttime, they have been used for many years.

Also in our profession there are lights that were used for movie lighting. One company involved was called Xenotech. Fantastic parallel beam lights were built by LP Associates, the company of Leonard
Pinfus, with whom we were related for many years.

Ideally, for our purposes we want a parallel or 'near-parallel' light beam that is clean and as homogenous as possible.

This is usually achieved with the help of a parabolic reflector. The parabolic reflector on its own is not suitable to provide such a clean, near-parallel beam, it needs a little bit of help. Therefore, our PB70 was carefully developed to include several shading rings at a carefully defined depth and placement.

Also, the light source should ideally be a point light source. Therefore, metal halide (HMI) light sources are very good, also some Xenon lights were able to provide a small point light source.

Xenon though, has some characteristics that are not ideal for movie lighting, skin tones and many other character evaluations. Xenon lights may be very useful to create moonlight effects at night in the forests.

We spent some efforts in developing a metal halide light source. The commonly used name HMI is a brand-name of Osram. Our lamp is not from Osram.
Our lamp features a very good homogenous color spectrum that continues its excellent characteristics throughout the entire lifetime.

In its original shape it was not the perfect light source, so we modified it somewhat in order to contribute to the homogenous light distribution and the smoothest near-parallel beam of our fixture.

There are several aspects to this light that are noteworthy.

A — The Virtual Light Source

Working with such a nearly-parallel light beam the light does not derive anymore from the light fixture (from within the housing of the light). It is to be seen in a virtual light source that derives from way behind the actual light fixture.

How do you define the virtual light source?

You elongate the outer rays of the beam backwards until they cross, and that's where the virtual light source is to be found. With the PB70 this is between 6 and 20 meters (20 to 60 feet) behind the instrument.

This feature on its own helps in many ways for the lighting in most of the productions where it is applied, because it enhances the distance from the working light source to the object. Thus, it diminishes the ill-effect of the square law, in other words, when our talent (the actor) moves, the change of intensity is not as noticeable as when the actual light source is closer by.

Thus, artificially, in this way extending the travel of the light before it arrives at the talent creates a lesser proportion for the movement of the actor in relation to the total length of travel that the light has to overcome. Therefore, the change of intensity is noticed much less.

You know of course that the inverse square law is defined at: double the distance = one quarter of the light.

There are different ways in which we can explain how to overcome these deficiencies, but dedolight Lightstream with the PB70 light is a very effective tool in this matter.

B — Power Economy

The PB70 consumes merely a maximum of 1200 Watt. But at the same time the output can be measured as 50% higher than an Arri 9 kW metal halide light in its narrowest spot position.

Thus, it becomes a very effective tool, and it can be used on regular household outputs with great efficiency. This is a major step in ecological aspects, Green Tech in the media industry.

C— Comparisons

This PB70 light fixture has been compared to almost everything available in the movie profession. For the James Gray film 'Ad Astra' with the DOP Hoyte van Hoytema extensive test were done, comparing all such other light sources in the attempt to look
for a lighting tool that would create the illusion of natural light coming from a very far distance.

Listen to the gaffer who was involved in the evaluation of all different potentially usable
lighting instruments. Adam Chambers.
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27th
Apr 2021

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