Sunday, April 1, 2007

MetroLux II Instructions, Installation

MetroLux II®


MetroLux II® was designed to overcome the problems of light output fluctuations associated with coldlight printing lamps. We watch the light while you print, correcting for fluctuations. It works fine with all light sources that do not exceed the 720 watt power requirement. Certain precautions must be followed when installing the probe:

* While installing the probe, be sure the light source you're working on is electrically disconnected from all power sources.

* Always strain relief the probe such that a tug from the outside cannot damage the tube or other parts of the printing lamp.

* Tie probe wire out of the way. As the enlarger moves up and down, be sure that the probe wire is not pulled or damaged.

* Avoid exposing probe or wire to heat. If it's too hot to touch, it's too hot for the probe (probe temperature range is -15° to 140°F). With some quartz and tungsten lamps, the probe wire will need to be mounted on the outside of the housing, away from heat. In this case, the probe can view the light through a small hole drilled near the source.

* The probe's-eye-view is very sensitive to changes in position. The probe should have a clear view of the printing lamp and not be allowed to move.

Sound pretty complicated? It's very simple. We've installed many probes in all kinds of lamps without problems. If you have problems, drop us a line.

For Coldlights.

Below is an installation technique we have used for the Aristo D-2 coldlight, the most common coldlight. If you have another type, these instructions should provide enough general information for fitting your coldlight with a sensor. Read the instructions through once before starting. Simple tools and a little smarts can perform the operation.


pencil, masking tape, screwdriver, electric drill with 1/8" and 3/8" bits.

1. Disconnect the power chords and remove the coldlight head from your enlarger.

2. Mark the relative orientation of the cap and bottom of the coldlight with a pencil.

3. Remove two small screws on sides of coldlight. Lift the cap off the coldlight.

4. Mark the location on the cap where the hole will be drilled. It must be located on the top such that the probe wire will clear the transformer beneath the cap.

5. Drill the hole with 1/8" bit and then widen the same hole with the 3/8" bit.

6. Clean the hole of any burrs and remove shavings from inside the lamp housing from inside the lamp housing.

7. Feed the probe wire through the hole in the cap. Now pass the probe end through the opening on the fluorescent tube mount board towards the tube itself.

8. Look closely at the probe and note which side "sees". It is the side with the shiny square eye. With eye away from fluorescent tube, strap wire to the tube near the center of the cold light grid with nylon cable ties at both 1/4" and 1" distance from probe. From here the sensor can see the 'average intensity' of the light. Pull snug and clip away the excess ties.

9. Realign cap on lamp; spin in the screws.

10. With the lamp reassembled, take up slack in probe wire by gently pulling excess wire out of cap. Take the strain relief (the strain relief is the odd-shaped, black thing in the plastic bag that the probe came in) and with the wire laid into the larger piece, force the other side in so that it clamps ('pinches') the probe wire. Use a pair of pliers to squeeze and snap this strain relief through hole

Probe strain relief, and close-up of assembly, in coldlight lamp house.

MetroLux II®


As a means of fastening the light sensor to some tungsten and quartz lamp houses, we have used the hole pattern shown below. With these holes, the probe is positioned over the 1/4" hole, with the wire trailing between the other four (4) holes. Nylon ties through the other holes fasten the light sensor wire to the housing. A drop of epoxy on the back of the light sensor holds it firmly in position.

Before drilling holes in the lamp house, we like to perform an experiment: With the light source removed from the enlarger, set up MetroLux II® and the lamp on a work surface. Unwind the light sensor and plug it into MetroLux II®. Set MetroLux II® to the Cal mode. Hit FOCUS to turn on lamp. Take the light sensor's eye and point it at your lamp. Watch the number displayed on MetroLux II® change as the sensor sees more light.

We look for three things in choosing a sensor location--a comfortable place to put the light sensor, a place where the light is fairly uniform, and a place where the number displayed is greater than 10. You'll find that all numbers between 10 and 900 work fine.

After finding the appropriate mounting location, end experiment by holding SETUP.

Other installation examples to mount your sensor:

Variable Contrast Coldlights:

MetroLux II® is designed for compensating for ouptut variations on single grade lamp sources. With a few considerations, it can also be used on variable contrast tubes with great success. Best results will occur when the sensor is attached to the Green tube looking at the Blue tube. This evens out the readings from the Green tube, which is 2-3 times brighter than the Blue tube. You can monitor the effects of your placement by switching between Green light only and Blue light only during the Calibration procedure. Best printing results occur when Green readings are similar to Blue readings.

It is also suggested that you choose a middle contrast setting to calibrate. This way the output variations on contrast changes will not be as large a swing from your calibrated value.

Many printers using the MetroLux II® on their VC coldlights are calibrating their LUX 2 channel for the highest contrast setting.

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Pocket Spot

Pocket Spot
Metering in the Office, 10 2/3 EVs

Pocket Spot

Pocket Spot
Metering in the Office, 4 1/3 EVs

Pocket Spot Spec Sheet

Pocket Spot Digital Light Meter Specs

Display: 2-digit Red LED with 1/3, 2/3 LED indicators

Dial: White, laser-engraved on Meter's anodized color background. Intermost dial is ISO with f/# on the outside. f/1.0 to f/128. Outer dial is shutter speeds from 8 minutes to 1/4000 sec on the inside and EV on the outside. EVs from -1 to 20. Body is marked with Zones from Zero to X (10). [Romans didn't have a zero, but what are you going to do? ]

ISO: 3 to 12800 ISO, marked in 1/3 stops

EV range: -1 2/3 to 23 at 100 ISO

Spectral Sensitivity: Compensated for "typical" B&W film, i.e. HP5+ or Tri-X

Angle of View: approximately 1 degree, smaller at very high EVs and 3 degrees at lower EVs

Viewing: Bore-sight through the hole the length of the chassis. Meter is held about 12" or 300mm from the eye (length of strap)

Linearity: about 1% from low to high.

Calibration: Not required. No adjustments inside.

Finish: Black anodized over a solid block of machined aluminum. Texture is random tumble over stones before anodize. Other colors in consideration at extra cost are RED and BLUE.

Battery: 6V PX28 or equivalent, Supplied

Dimensions: 2.25" x 2" x 3/4" (L x W x T) 57 x 50 x 19 mm
Dial on top is 1/8" thick, 3 mm

Weight: 4 1/8 oz (117 grams) with strap and battery, both included.

specifications subject to change

More pictures on page two near bottom.