Dimmers allow changing  the intensity of the luminous flux of sources of light.

Dimmers are connected to the three-phase current source (380V) that is regulated and led directly to the individual lights from individual channels.

We discern between stationary (built-in) and mobile (portable) dimmers according to their location in the theater.

Type designation of dimmer units typically contains two numbers (format: number / number), where the first one indicates the power input of one circuit and the second one the number of circuits. (Example: 2/12 = twelve independent circuits with the individual performance of 2kW per circuit) The number of circuits indicates how many instruments can be independently controlled. Power of a circuit indicates what maximum performance we can connect to the circuit (one fixture or several – performance adds up).

The most commonly used power values ​​ of dimmers and possibilities of wiring of lights:

Lighting control desk, console, board    

It is used to control the dimmers. Lighting consoles are basically divided according to the output signal into analogue (0-10 V) and digital (protocol DMX).

An analog lighting console – entering the output values of the circuit is served by the  ​​auxiliary voltage (range 0-10) that is directly adjustable by a tension potentiometer on the console. Each circuit, controlled by analog lighting console, must have its own conductor between the console and dimmer. Such a kind of a solution is now obsolete and not used.

A  digital lighting console is basically a computer that communicates with the dimmer units via the DMX 512 protocol, which is a serial digital protocol that can transmit up to 512 parameters at once.  The protocol DMX 512 is a worldwide standard, which can also control other device with DMX.

Barn doors for a PC or Fresnel.

Four tin sheets allow confining a beam or reduce stray light. They are most commonly used in types as PC, Fresnel, but exist for the PAR and floods as well.

In profiles, there are blades, with which the light beam can be cut into a certain shape (according to the number of blades). The term is also used for the shutter in front of the lens of the projector.

Two standardized and one home made Gobo with a goboholder in the middle.

– Gobo (go before the optic):

A steel or glass template that releases light in a certain shape or pattern (bitmaps, texts, geometric shapes, trees, etc.). A steel gobo is carved, glass gobos are printed, and can be colored. Gobos are used in instruments with adjustable optics (profiles) that allow focusing the shape. Some fixtures offer rotary gobos – the shape can rotate at the desired speed.

An Iris is a mechanism that allows reducing the light beam by its mechanical closing, reducing light output (as opposed to “zoom”, where the beam is reduced by movement of two lenses in relation to each other). An Iris diaphragm with blackout enables  closing  a light beam completely (used in followspots). In other words, an Iris diaphragm enables changing the angular range of the light beam.

An Iris without a blackout: even when the diaphragm is fully closed, the light still penetrates in a narrow beam.

The principle of diaphragm.

Iris diaphragm.

Special heat-resistant foil fixed in front of the lens allows adjusting the light beam with a wide range of colors or modifying its color temperature. Filters with enhanced heat resistance are called HT (high temperature). Specific filters of the  “frost” type are used to achieve the desired dispersion of the light beam.

Lee Filters is an established manufacturer of color filters and corrections for theater, film and photographic lighting. The complete range of filters is always clearly marked by a three-digit number (introduced with letter “L”) and the name of the color or correction (e.g. L141 Lee fluorescent 5,700 K – correction filter of a tungsten source for cold fluorescent temperature of 5700 K / daylight, L245 Half plus green – no correction filter, so it doesn’t state the chromatic temperature, it is used to add a green component). More at  www.leefilters.com.  There are other manufacturers (Rosco, GammColor) with their own product series and titles.  However, a three-digit number is used among all of them.

Examples:

Lee 202 – ¼ CT Blue: a numerical designation of a filter by manufacturer Lee filters, CT Blue – “color temperature blue”, this is a correction of a tungsten source to the daylight temperature, in this case by the value of ¼ CT Blue (Lee 200 – full CT Blue, Lee 201 – ½ CT Blue)

Lee 242 – 4300 K fluorescent: a numerical designation of the filter by manufacturer Lee filters, here with tungsten correction of the source for fluorescent temperature of 4300 K.

Scroller is a type of a color changer. It is a mechanical device for rewinding filters that is fixed in front of the optics of a conventional fixture, being controlled by a DMX command, it can change the color of the beam.

A scroller on a PC.

A classic three-legged stand is used for placing the instruments into a position where there is no suspension point available. It can be complemented by a “T bar”, and thus carry more fixtures. The telescopic extension of the tripod is variable according to the type  but typically from 1.5 to 6 m.

Allows to securely fix the direction of the instruments, placed on the floor.

A ballet tower is a telescopic cubic structure with  standard height of about 2 m and with a possibility of further extension, which can carry several instruments, one above the other, which allows the use of different angles of the light beam, and is thus more practical than the traditional tripod.

A Show foil is composed of a special material with certain specific light transmittance and reflective qualities, permitting lighting through or projection both from rear and front.