Source four

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Source Four ERS

Electronic Theatre Controls (ETC) Source Four is an ellipsoidal reflector spotlight, a type of spotlight used in stage lighting. The ETC Source Four revolutionized stage lighting in 1992 ^[1] with the introduction of revolutionary lamp and reflector technology, tool-free lamp adjustment, and a rotating, interchangeable shutter barrel. The Source Four ERS is the most widely used Ellipsoidal Reflector Spotlight among professional theaters in the United States^[2].

1 Glass Reflector
2 Tool-free lamp adjustment
3 HPL Lamp
4 Barrel
5 Enhanced Definition Lens Tube
6 Other Source Four products
7 References

[edit] Glass Reflector

The Source Four is the first ERS to use a faceted borosilicate reflector behind the lamp^[3]^[4] . Nearly all stage lights have some form of reflector positioned behind the lamp to reflect otherwise wasted light out the front of the instrument. The Source Four's unusual reflector is dichroic, meaning that it reflects light of only certain wavelengths. The Source Four's reflector reflects back 95% of the visible light striking it, while allowing over 90%of the infrared radiation (heat) to pass out the back of the instrument ^[1]^[5] . This produces a much cooler light which is less destructive to gobos or colour gels at the front of the fixture.^[6]

[edit] Tool-free lamp adjustment

Lamp adjustment is used to achieve an even field of light, and to remove hot-spots which can destroy color filters. On the Source Four, adjustment can be done without tools, and is more accurate than previous fixtures, which makes it easier than the previously common four screw assembly that can be challenging for many professionals. Lamp adjustment is often known as "bench focus" and is periodically done with all house units to avoid units that are poorly bench focused during focus.

[edit] HPL Lamp

The HPL lamp uses a compact filament, which produces the most light where it is efficient in an ellipsoidal reflector^[7]. At 575 watts, the HPL lamp in a Source Four produces light equivalent to a 1000 watt spotlight using previous technology. This lower amount of energy consumption saves money on electricity and creates less heat.

[edit] Barrel

A Source Four with a 10 degree lens on the front (left)

The Source Four is the first fixture to feature a rotating shutter barrel^[8], which make framing objects or controlling spill much easier than previous fixtures, where the shutters had only a limited range of motion and could not be rotated. The shutters are also made from stainless steel, which does not warp easily under the heat of the lamp.

ETC also offers a variety of interchangeable barrels with various beam spreads. Barrels include: 90, 70, 50, 36, 26, 19, 14, 10, and 5 degree barrels, Enhanced Definition Lens Tube (EDLT), and Zoom barrels. Different barrels are better for different venues with different catwalk and electric systems^[9].

[edit] Enhanced Definition Lens Tube

In 2005, ETC introduced the Enhanced Definition Lens Tube (EDLT). The EDLT is designed to produce crisp images from gobos and graphics. The lenses use lenses in the tube are coated with an anti-reflective material and are machined to more exact standards than the standard Source Four lens. The ELDT also increases lumen output. It is available in 19, 26, 36 and 50 degree barrels.

[edit] Other Source Four products

In 1995, ETC introduced the Source Four PAR which is meant to replicate the performance of PAR cans while lessening the disadvantages involved with traditional PAR cans.

In 1999, ETC introduced the Source Four PARNel as an alternative to fresnel lanterns.

In 2002, ETC introduced the Source Four MultiPAR as an alternative to striplights.