Last Updated 2 hours ago
Overview
The Type 8181 takes one 2 kW lamp behind an 18-inch reflector. At 20 ft it gives 110 fc in spot across a 14.9 ft field, or 50 fc in flood across 27.2 ft. The focus ring can be worked by hand or with a pole.
Key specifications
| Specification | Type 8181 |
|---|---|
| Maximum head load | 2,000 W, 16.7 A at 120 V |
| Reflector | 18-inch Molebrite Alzak aluminium scoop |
| Focus | Hand or pole via rear 1½-inch ring |
| Socket | Mogul screw, E39 |
| Size with standard diffuser clips | 20¼ × 20⅜ × 20⅛ in. |
| Head weight with clips | 12¾ lb |
| Head weight with square holder | 15¼ lb |
Replacement lamps
| Lamp | Power | Voltage | Rated colour | Finish | Rated life |
|---|---|---|---|---|---|
| BWG | 2,000 W | 120 V | 3,200 K | Frosted | 500 h |
| BWF | 2,000 W | 120 V | 3,200 K | Clear | 500 h |
The BWG is frosted and the BWF is clear. Both are 120 V, E39 mogul-screw lamps. Mole measured the published beam with the BWG.
Strengths and limitations
- The focus ring changes the field width at the same throw. At 15 ft the centre reading runs from 90 to 200 fc.
- The reflector has a gradual edge. For a clean cutoff on scenery, set a flag where it can catch the spill.
Practical uses
For a standing set with a wide master and a tighter insert, trim the spread from the grid without moving the head to another pipe. Spot raises the centre level as it narrows the field, so record the focus position along with the dimmer cue.
Output and photometrics
The figures are centre-beam foot-candles. Field diameter is the width at approximately half the centre intensity. Mole tested the BWG at 120 V. The table shows both ends of the focus range.
| Distance | Flood (fc) | Spot (fc) | Flood field | Spot field |
|---|---|---|---|---|
| 10 ft | 200 | 450 | 13.5 ft | 7.5 ft |
| 15 ft | 90 | 200 | 20.4 ft | 11.2 ft |
| 20 ft | 50 | 110 | 27.2 ft | 14.9 ft |
| 25 ft | 30 | 70 | 34 ft | 18.7 ft |
| 30 ft | 20 | 50 | 40.8 ft | 22.4 ft |
| 35 ft | 15 | 35 | 47.6 ft | 26.1 ft |
| 40 ft | 10 | 30 | 54.4 ft | 29.9 ft |
Photometric & exposure calculator
Estimate centre-beam illumination and the corresponding camera aperture from this fixture’s published measurements.
Estimated output
Select a configuration to calculate.
Manufacturer readings are for the stated optic, colour setting and full output, measured at the beam centre. Values between measured distances are interpolated. Point-source values outside those distances are approximate inverse-square estimates; large sources cannot be reliably extrapolated and are limited to their measured range. Exposure uses frame rate, shutter angle, ISO and the selected incident-meter calibration. Only the optics and diffusion explicitly listed in the measurement are included; additional modifiers, bounce, beam edges, ambient light, ND filters and camera exposure-index differences are not accounted for. Confirm critical exposures on set with a meter. Photometric source
Power and controls
The head is rated for 120/240 V AC or DC. The 2,000 W catalogued test lamp draws about 16.7 A at 120 V. Mole supplied the standard head with 36-inch leads and no switch. The optional 25 ft cable had an inline switch. Confirm the plug and lamp voltage on the unit being booked.
Optics and mounting
The standard Type 81885 diffuser clip ring takes material at the front. Mole also lists a Type 8185 square holder and a Type 81849 Molequik frame. The Type 8183 junior pin fits mounts with a 1⅛-inch receiver, and the yoke accepts ½-inch mounting hardware.
Comparable fixture
The companion fixed-focus head has the same reflector diameter and its own field and output table. Mole-Richardson 18-Inch Fixed-Focus Scoop (Type 8182).
Field coverage and further reading
An ANJAC Studios West equipment list records six Type 8181 scoops. B&H also lists the 15 ft spot setting at 200 fc across 11.2 ft, matching the manufacturer chart. ANJAC Studios West equipment list.
Rental and used-fixture checks
Check the focus ring under the actual hanging angle. Verify that the yoke pin and the fitted cable suit the booked mount and dimmer, and that the package includes the correct size diffuser ring.
Documentation
- Original Mole-Richardson specification and photometric sheet
- Mole-Richardson equipment catalogue
- Download the original scoop sheet
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