Arri M18

The Arri M18 is an HMI, which stands for Hydrargyrum Medium- Arc Iodide. This fixture is a par style and has a wide beam spread. The M series has an updated reflector that increases output and creates an even beam removing the need for lenses. HMI bulbs range from 5000-7000 degrees kelvin. M18 is highest wattage HMI able to be plugged into a household circuit.

M18 Lamphead

Uses

• Hard light - Shadow quality with the par style is not great for hard shadows
• Soft light - Wide beam spread helps fill diffusion in a shorter distance.
• Day interiors - Outside of windows pushing light in or used inside usually as a soft source.
• Day exterior - Very limiting because of low output.
• Night exteriors - Common use is to mimic moonlight or mercury vapor.
• Depending on camera white balance, it could have many more uses.

QC Process

QC Process for All Lights

Accessories

• 13.5” scrim size and comes with two full doubles and a full single because it is a par fixture.
• It can also be used with a 1200w globe
• OctaBank

Troubleshooting

HMIs are inherently problematic and the m18 has some common issues.

• Check all switches. A common problem is the switch is off at the head.
• The molded head feeder is often a point of failure, more so than other head feeders. You can test for a bad head feeder by plugging the light directly into the ballast and trying to strike it.
• The safety switch located on the head will sometimes stick. You can test this by pushing on the UV glass on the front face on the light or opening and closing it.
• The dimmer on the M18 will not work unless the light is fully up to speed. To check if it's up to speed you can check the ballast and look at the indicator light that says 1200w or 1800w. If it's solid yellow it is up to speed, blinking means not there yet.

Substitutions

There are not many substitutions for this light, but the following lights could be used in place of one if they are willing to take a slightly different fixture.

• S60 Skypanel - Softer, but similar intensity and they get dimming, bi color, and RGB.
• Aputure 600D - Not as bright, but similar style unit.
• 1600w Joker - This is k5600s answer to Arris 1800w Par. Very similar brightness even though it is different wattages.
• Tungsten 5k - If they are on stage and want HMIs, they can swap with equal sized tungsten units.