Friday, May 4, 2007

MetroLux One Instructions, beginning

MetroLux model one instructions.


Copyright © 2007 by Metered Light LLC. All rights reserved. Metered Light LLC makes no representations or warranties with respect to the contents hereof and specifically disclaims any implied warranties of merchantability or fitness for any particular purpose. Further, Metered Light LLC reserves the right to revise this publication and to make changes from time to time in the content hereof without obligation of Metered Light LLC to notify any person of such revision or changes.

Operation of MetroLux in the Lux mode requires the installation of a light sensor in your printing lamp. Metered Light LLC is not responsible for such installation nor shall MetroLux or their dealers be held liable for ill effects caused by poor or faulty installations.
MetroLux, A Darkroom Lamp Controller and Metered Light are trademarks of Metered Light LLC. All printed wiring boards, silkscreens, software, and firmware are copyrighted and are property of Metered Light .

Revision 2.3
June 2007


Thank you for purchasing a MetroLux Lamp Controller. We believe it is the finest device of its kind. It's a timer, a metronome, a 'lamp controller', and you'll find it to be much more. Installation instructions start below.

The name MetroLux literally means 'metered light'. Because it is a light-based "timer", MetroLux measures light output (Lux) as you print. As you know, all conventional darkroom timers use conventional seconds to control exposure. But what happens when the air-conditioner turns on and the line voltage to your printing lamp drops? Printing with MetroLux in the Lux mode, the scientist next door can brown out the entire city, and your prints will STILL come out just as you planned.

MetroLux is a particular godsend for fine printers with coldlight enlargers. They know a fluorescent-based lamp source can fluctuate from exposure to exposure. A coldlight, warm from constant use, can print up to 1000% heavier than a cold coldlight. MetroLux exposures in the Lux mode vary less than 1/2 %.
Before you can use MetroLux as a lamp controller, you will need to install a photo detector 'probe' into your printing lamp. This allows MetroLux to monitor your lamp's output and thereby control it.

Warning: This MetroLux is equipped to handle lamps up to 720 Watts. DO NOT EXCEED THIS POWER LEVEL. Damage to your MetroLux may result. (MetroLux Lamp Controllers are available for higher wattage lamps. Contact Metered Light.)

Getting Acquainted
To acquaint you with the functions of your lamp controller, plug your enlarger lamp into the AC outlet on the back of MetroLux. Connect the probe into the probe jack, also on the back panel. Turn on MetroLux by pushing the On/Off Switch. See drawing of back panel below.

With MetroLux turned on, we are ready to demonstrate how the probe operates.
Depress the 'Unit" key until the CAL LED is lit. Press the 'Memory' key twice until LED #3 is lit. Turn on your enlarger lamp by pressing the 'Focus' key.
The numeric display will probably read 00. Take the sensor end of the photo probe and move it towards your lamp source (in the negative stage is fine). The closer the sensor gets to the light, the larger the number displayed. The sensor is reading the light intensity.

How The Keys Work

The use of MetroLux will soon become second nature, but first let's examine the use of each key.

On/Off Switch

Located on the back panel, this switch powers MetroLux.


This key selects Lux, Cal, or Sec. The LEDs on the left of the display indicate which mode has been selected. A single push of the key toggles between Lux and Sec (seconds). Holding the key down takes you into the calibration mode.

LUX Primary mode. The printing lamp is monitored; the exposure is controlled.
CAL This is the calibration mode. (See below.)
SEC Secondary mode. Exposures are based on time. Probe is not required.


This key provides access to the 4 memories of the stack. The LEDs on the right of the display indicate which memory is active.
When in the Lux or Sec modes, the first three of these memories are for exposure 'times'. The fourth is a percentage factor, explained below.

As you push the Memory key, you will see the Memories roll by: #1...#2...#3...#4...and back to #1 again.

When in the Cal mode, the memories serve a different function explained below.


These two keys set the numeric display to the desired number. A brief push of either key will change the display one tenth of one count. Holding the key down will cause the display to count at a moderate rate. To count faster, hold both keys down. The first key down determines the Up or Down. The other key acts as a accelerator and provides an accelerated rate of counting.


This key turns on your enlarging lamp. The lamp will stay on until the key is pushed again.


This key turns on the lamp and starts the counter simultaneously. This is your printing mode. It can be used in Lux or Sec modes.

You can terminate the exposure at any time by pushing this key.


If you purchased a footswitch, it plugs into the back panel. Depressing the footswitch is the same as depressing the 'Start' key on the front panel.

Beep, Volume Control

When the printing lamp is on, a beep is heard. The beep comes every Lux or second depending on the 'Units' selected. The volume of the beep may be controlled by the adjustment of a screw accessed through the hole on the front panel. As the screw is turned the volume will change as will the pitch. Please note, this adjustment screw rotates 3/4 turn only. The beep can also be turned off entirely. See Custom Code Numbers. Optional louder beeper are available for noisy darkrooms. Also, for those with a hearing deficiency in the higher tones, a lower pitched beeper is available---the "deeper beeper". (Sorry, the deeper beeper is no longer available.)

Thursday, May 3, 2007

MetroLux One Instructions, middle


NOTE: Before you calibrate, a probe must be installed in your light source. See installation instructions.
To operate MetroLux with your enlarger, you must introduce the two in a ceremony we call Calibration. Every enlarger has a 'standard' light output. What we need to do is determine the standard light output from your enlarger and inform the MetroLux. Please follow the next steps closely.
EXAMPLE: Hold down the 'Units' key for one second until the Cal LED is lit. The #1 LED (calibration #1) on the right side should also be lit. If not, roll the memory by pushing the 'Memory' key. With each push the display goes from #1...#2...#3... #4...and back to #1 again.

Turn on printing lamp by pressing 'Focus'. (Coldlight people, allow lamp to warm up...five or ten minutes).
Push 'Start'. You are now calibrated. Be sure that LED #1 is lit. Leave the Cal mode by pushing 'Units'. You may never have to calibrate again. More details about calibration are given in Advanced MetroLux below.
One last note about the calibration number. The optimum number is between 10 and 127. If the calibration number falls outside this range, accuracy suffers and MetroLux may make mistakes.
Write your calibration number down. True, MetroLux does have non-volatile memories, but it's still wise to protect yourself from darkroom gremlins.
Should you get a number less than 10, there are three possibilities: the probe is not plugged into the back of MetroLux, your lamp is not warmed up, or the probe is not seeing enough light. In the latter case, you'll have to move the probe. For numbers greater than 127, the probe is seeing too much light and is too close to the source (and is probably too hot).

Advanced MetroLux

Exposure Memories #1, #2, & #3

MetroLux has three of its memories dedicated to exposures. This gives you three different exposures to work with without constantly changing the memory. There are many ways to use these three. Our favorite is to keep the base exposure in Memory #1, the test strip exposure in #2, and our proofing exposure in #3. If all these memories are troublesome, #2 & #3 can be masked. See Custom Code Numbers.

Relative Exposure Control: The Percent Function

When would you use the percent function?

To apply dry-down factors.
The dry-down effect is best explained in The Print by Ansel Adams, page 82.
To wit: most photographic printing papers become slightly darker as they dry, most noticeably in the highlights of the print. To determine the value of this dry-down effect, expose a normal print . If it looks good wet, print another 5% lighter. As it dries it will match your wet print. (Nominal dry-down factors range from 1 to 11%.)
To have MetroLux apply this predetermined dry-down, press 'Memory' key until the % LED is lit. Using the 'Down' key, set the display to 95%.

Press the 'Memory' key again until the #1 LED is lit with your printing 'time' displayed. The #4 LED will also remain lit reminding you that your exposures will now run 5% shorter and the metronome will beep 5% faster. Whenever the % factor is other than 100%, the % function LED remains lit as a reminder.

The % function affects ALL exposures, in Lux or Seconds mode, Focus or Start (exposure). Before work on another negative begins, it is important that the % function be reset to 100%.

To incorporate 'fudge factors'.

You'll notice that the % function has a very large range---50 to 200% (plus or minus one f/stop.) This is much more than necessary for dry-down compensation. Why the overkill?

Consider the negative printed regularly. It would be nice to always use the same exposure for making that print -- regardless of the paper's type, grade, serial number, or age. You would simply pull the negative from your file, transfer the notes from your prior printing into MetroLux, and make the print.
But say you desire an enlargement 20% greater than the notes on your negative sleeve dictate. Use your original exposure with a 120% factor.
Or say you are unhappy with a print made on #3 Oriental. Too flat? Whip out the box of #4, plug the predetermined emulsion speed difference factor into the % function, and print the compensated print.

More Calibration

If you have a second lamp, with a photo sensor installed, it is possible to store its Calibration number in Memory 2.
EXAMPLE: You use a coldlight but sometimes print with a tungsten light. You've already calibrated your coldlight in Memory 1. Now calibrate your tungsten in Memory 2.
To use Memory 2, press the 'Memory' key until LED #2 is lit. Calibrate as with lamp #1.

Remember, when entering Cal mode, whichever calibration number is displayed, 1 or 2, that is the one you were using. Whichever memory is displayed when you leave the Cal mode is the Calibration number you will be using. You cannot leave the Cal mode without being in Memory 1 or 2.
For those of you using two light sources with one MetroLux, there are ways of configuring the wiring so that plugging and unplugging of light sources and probes can be eliminated. You will need a Y-adapter for the probes. See the list of options at the end of the instructions.


A second way to enter the calibration number is to input directly using the 'Up/Down' keys. With the lamp off, run the display to the calibration number you want. Again, you are limited to numbers between 10 and 127. This feature can be handy if you want the beeps to come at longer or shorter intervals...other than the approximate one second interval achieved through calibration. Say you'd like the beeps to come at two second intervals. To do this, double the calibration number.

Lamp Intensity Monitoring

If you were wondering what happens when MetroLux is in Cal mode-Memory 3, wonder no more. This function displays the lamp intensity as monitored by the probe. It is a real-time readout of the light source intensity. It is the number that MetroLux would store in Memory l or 2 if you were to proceed with the calibration procedure. This number is directly proportional to the intensity of the lamp. If you're using a cold light, you may notice this number change dramatically as your lamp warms up.

Custom Code Number

When MetroLux is in Cal mode-Memory 4, some adjustments can be made to your Lamp Controller. You can: (1) turn the beep off, (2) hide Memories, and (3) control LED brightness.
{Notes inside these brackets refer to the Custom Code Number chart below.}

Beep {B}
Turns the beep off. {B is beep on, dash is beep off.}

Memory {M}
With this adjustment, a push of the 'Memory' key will toggle between Memory 1 and Percent, bypassing Memories 2 and 3. This is convenient when using only one printing exposure. {M is all memories, dash is Memory 1 and Percent.}

LED Brightness {1,2,3,4}
There are four levels of brightness for the LED display. {3 is standard and factory set. 4 is one level brighter. 2 is dimmer. 1 is very dim.}

Your Custom Code Number

Decide on the set-up that you'd like, look up the corresponding bold number in Table 1, and enter the number as explained below.

EXAMPLE: Let's say you'd like the Beep on but want the Memory to toggle between #1 and %, and the LEDs dimmed a little.
Keep the Beep...that's a B. Toggle the Memory...that's a dash. Dim the LEDs...that's a 2 on the end. Get the order correct. Look up 'B - 2 ' below.
Here it is again in table form.
function choices example
Beep B - B
Memory M - -
LED Brightness 1 2 3 4 2

Custom Code Number Selection.
If we take 'B - 2' below, we can look up the custom code number. Going down the list we find that it is equivalent to 13. This is the number we wish to install in Memory 4 of the Cal mode.
In the Cal mode, go to Memory 4. Enter '13' into the display using the 'Up/Down' keys. (See Figure 7.) Simple. The lamp need not be on.

Cal Mode, Custom Code Number

00 - M1
01 - M2
02 - M3
03 - M4
04 - - 1
05 - - 2
06 - - 3
07 - - 4
08 BM1
09 BM2
10 BM3
11 BM4
12 B - 1
13 B - 2
14 B - 3
15 B - 4

Table 2. Custom Code Numbers

Jot down your favorite custom code numbers for future use. This can save a lot of time later. (The 'factory set' custom code number is 11.)

Memory Reset
The table below shows the location and use of all seven (7) memories in MetroLux, their names, and their factory preset value (bold numbers). You may reset these numbers at any time. To do so, turn on MetroLux while depressing the 'Units' key. Pressing the 'Start' key places the numbers into non-volatile memory. If you want your old numbers back, turn off MetroLux before pressing the 'Start' key. When you turn MetroLux on again, the original numbers will still be there.

Cal Mode Printing Mode

# 1 Calibration 1 (16) Lux/Sec 1 (1.6)
# 2 Calibration 2 (16) Lux/Sec 2 (1.6)
# 3 Light Intensity Lux/Sec 3 (1.6)
# 4 Custom Code # (11) Percent (%) (100)

Very Early MetroLuxes (serial numbers a little larger than 923)

These MetroLuxes don't have a power on reset. Here is how to tell if you have one these 'very earlies'. Go to the Custom Code area and see if the range is 0 to 15 or 0 to 127. The latter is a 'very early'. Fear not. These work fine, but have spots for features that were never incorporated. The Custom Code numbers are the biggest problem and I don't have the table anymore (It is in an old Mac computer. If you have a table and could make a copy for me, that would be slick.)

Here is how the old table worked. There are four controls: count by tens/halves, one or three time memories, beeper on or off, and 4 brightness levels.

Brightness levels change every count. 3 is brighter than 2 is brighter than 1 is brighter than 0. This repeats all the way up to 127. Brightness is bit 0 and 1 (if you know the binary here).

Bits 2 and 3 don't control anything and thus everything repeats with these bits.

Bit 4 is the Beeper on/off. So the beeper is off from 0 to 15 and then on from 16 to 31, etc.

Bit 5 is the Memory, either one or three. Memory is all on from 0 to 31 and only one from 32 to 63, etc.

Bit 6 is the count by 0.5 or 0.1 settings. Counting by 1/10 with the custom code number from 0 to 63 and counting by 1/2 from 63 to 127.

The old factory settings on these units was 20, but I like 23 for brighter LEDs.

If the unit acts weird, make sure the percent is between 50 and 200.

Thanks to Paul Rice for this lesson with older Metrolux units.

Tuesday, May 1, 2007

MetroLux One Instructions, end

MetroLux has a variety of different light sensors available for all kinds of light sources and configurations. If you don't see what you need, drop us a card with information about your special needs. Standard equipment currently available for MetroLux is listed below.

THE STANDARD LIGHT SENSOR. This sensor is attached to a 72" cord. The sensor end you will permanently attach to your printing lamp, the free end is plugged into the back of the MetroLux.
ZONE VI ADAPTER. This is not a sensor, but a 72" cord that adapts MetroLux to the Zone VI cold light.
LIGHT SENSORS FOR DUAL GRIDS. For those using dual grid (two tube) cold lights , you may wish to use two sensors and a Y-connector that 'adds' the light together.
FOOTSWITCH. A footswitch with a 72" cord is available. We find it very convenient. It can be used to operate either the Focus or Start key. This choice was made at the time of purchase.
EXTENSION CORDS. Sometimes it's further from you light source to MetroLux than you think. If you need an extension, we offer a 72" probe-extension cord.
Y-ADAPTERS. For use with dual grids or when using MetroLux with two light sources.

Final Reminders
Care and Maintenance
MetroLux should be maintenance free. It is internally fused for you and your equipment's protection. If you feel that a fuse is blown, DO NOT ATTEMPT TO REPLACE IT YOURSELF. Refer all internal maintenance to qualified personnel.
Never open, dismantle, disassemble, modify, or insert anything into MetroLux.
If you'd like to clean MetroLux, we recommend a damp cloth and a mild soap. If necessary, the light sensor window may be cleaned with ethyl alcohol.
MetroLux runs best on 120 volts AC at 60 Hz. That's normal in the USA. For your protection, be sure MetroLux and your light source are grounded--don't defeat 3-prong plugs.
There are no batteries in MetroLux.
Obey the warning below and your MetroLux should be happy for a long time.

Appendix A

Installation Instructions
MetroLux was designed mainly to overcome the problems of light output fluctuations associated with coldlight printing lamps. It will work fine with all light sources that do not exceed the 720 watt power requirement. However, certain precautions must be followed when installing the probe in the light source.
(The probe is packed in a separate plastic bag. It has a plug on one end and a probe on the other.)

A. Unpack MetroLux (MetroLux, probe on 72" cable, plastic strain relief, 4 nylon cable ties).
B. General installation instructions for ALL LIGHT 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 several inches from the source. See below.
* 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.

C. FOR COLDLIGHT HEADS: Below is an installation technique we have used for the Aristo D-2 coldlight. The is the most common coldlight. If you have another type, read these instructions for tips on installation in your coldlight. Read the instructions through once before starting. Simple tools and a handyman's logic can perform the operation.
Tools: 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 the small screws on the side of the 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. (Some hi-intensity cold lights may run TOO HOT for this strapping technique. Check the 'on-temperature' of your tube.)

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. See Figure 2A.

As a means of fastening the light sensor to some tungsten and quartz lamp houses, we have used the hole pattern not 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 and the lamp on a work surface. Unwind the light sensor and plug it into MetroLux. Turn MetroLux to the Cal mode, Memory 3. (See CALIBRATION) Turn on the lamp, 'Focus' key. Take the light sensor's eye and point it at your lamp. Watch the number displayed on MetroLux change as the light sensor sees more the light.
What we look for is three things--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 127 work fine.

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.