how to use a Zelox enlarge-O-meter?

[Paul Byrnes]

Chan
That makes perfect sense. Thankyou. I now understand what Bill was trying to tell me. And by metering different parts of the test neg, I can get an idea of the ranges in play too, which should teach me more about judging the densities of any given neg - which I am still having trouble with. I will give it a try. And I guess I need to do it again with different papers and film stock combinations.
Mystery solved. Thanks to all.

PB

[Nicholas Lindan]

Pretty simple, really.

First make sure the unit works...

Check the sensitivity control:

1. Place the probe under the enlarger with no negative;
2. Set the 5-10-20 switch to 5;
3. Turn the sensitivity knob to the max;
4. Adjust the aperture and head height so the needle indicates the minimum time on the scale;
5. Turn the sensitivity down and see the needle swings freely;
6. Repeat for the 10 and 20 switch settings, the sensitivity control will need to be lowered with each change of the switch;
7. When switching ranges the needle should indicate the same time on both scales.

To check the the range switch:

1. Set the switch to 5, adjust the aperture and sensitivity control so the needle is centered on the '5' scale, raise or lower the enlarger head if needed;
2. Close the aperture one stop, the needle should indicate 10 on the '5' scale;
3. Turn the switch to 10, make sure the needle points to 10 on the '10' scale;
4. Close the aperture 1 stop, make sure the needle indicates 20 on the '10' scale;
5. Set the switch to 20, the needle should indicate 20 on the '20 'scale.

To calibrate for a specific paper:

1. Make a just-not-white print with no negative - stop the lens down as the time should be around 7 - 15 seconds;
2. Place the probe under the enlarger - all safelights need to be off;
3. Set the range switch on 10, twiddle the sensitivity knob until the needle points to the time you used to make the print;
4. Note the sensitivity knob setting - this is the speed/sensitivity to create a just-not-white tone on that paper;
5. If you are out of range then use the 5 or 20 switch/scale;
6. If you use VC filters then you should meter with no filter but make the print with a filter.
7. You can repeat for any tone you wish. A paper will have a sensitivity setting for every tone it can produce.
8. A step tablet can let you find the sensitivity settings for a wide variety of tones with just one print.

Use:

1. Place the probe where you want your white point to be - or any other tone for which you know the sensitivity setting;
2. Set the sensitivity knob appropriately;
3. Read the time from the meter, adjusting the 5/10/20 knob to let you use the most readable scale - ie, the needle towards the middle of the range;
4. Adjust the aperture up or down if you want more or less printing time.

[Tony Egan]

...and then stumble into bed exhausted without having made one print! Trust me, trying to master this will do nothing for your printing in the long run. The seduction of a "miracle meter" is enticing but ultimately futile. Keep it as a museum piece in a glass cabinet and let your eyes and your test prints be the judge...

[Paul Byrnes]

Thanks for the exhaustive advice Nicholas - but how do you know when you have made a good just not-white-print? Is there an accepted definition? I'll give it a try.
Tony - I may never use it for much, but it's just one of those mysteries I had to solve. LRT. The tapestry that is rich.
Thanks to all for the help.
PB

[Nicholas Lindan]

how do you know when you have made a good just not-white-print?

Not a print, a test strip/test patch/whatever. A just-not-white tone, the first one that is different from the white of the paper. Make the test strip at 10% intervals or so.

[Paul Byrnes]

Nicholas, thanks for the clarification. Much obliged. I get it now.
PB