Cibachrome Exposure Monitor M-1 and B&W
In my recent acquisition of free darkroom material from an uncle, I got in the lot a Cibachrome exposure monitor, but without the instruction manual. He couldn't seem to remember how to use it either. Moreover there's not much info about it I could find on the net or on Ilford's site, so I'd like to ask any color experts here what they can tell me about its usefulness for black and white printing.
The thingy is a little black box, with a white console on which there is a on/off switch, a small rectangular area on the left with a little hole that I assume to be the photosensitive cell, and a dial graduated from 0 to 100, labelled "Caliration". Finally on the left of the dial there are two LEDs, labelled "high" and "low".
I'm quite sure you have an early model of Ilford's
Originally Posted by mhv
current EM-10. That "thingy" is an enlarger spot
exposure meter. I suppose it might be used with
color but is for B&W.
As is it's main use is for making exact same
exposures at different magnifications. Some
calibrate the device against a step wedge then
use it as a densitometer. Dan
I have one of those. Like Dan says, once you get it calibrated with a good print, it works quite nicely. For calibration, I usually chose a good neg with a person in it. That way I can cailbrate for flesh and edge. Once you get a good print, note the time you are using and then place the area for metering as close to underneath the lens as possible. Off angle will skew the calibration. Once in the centre, just adjust the dial until BOTH LED's are off. That's it. Now you should be able to chose another neg with a flesh tone in it, size, focus, and use the meter to get a reasonable close aperture. it is nice for consistency for B/W.
For other calibration areas, just note the setting on the dial for each area and off you go. I use mine mainly for printing contact sheets (edge setting for max black), so I am then able to see how much my exposures were off
Sounds like I have an interesting find! It having "Cibachrome" in the name, my assumption was that it was only for colour work, you see...
I'm glad you guys could help me figure it out, but I'll have a few more questions still because I'm not entirely clear how the device works and what it records.
Dan, how do you report exposure information from one size of enlargement to another?
Canuck, when you say "as close to underneath the lens as possible", you mean in direct line of sight with lens? Once I have made the LEDs shut off for a given negative, what does that mean? i.e. does it mean you have found the proper exposure time? Or just that the meter has recorded some data?
What do the dial mean? Is it a number of seconds, a percentage of exposure time, an intensity of light?
As electronic devices go now days your M-1 and my EM-10
Originally Posted by mhv
are almost too simple to understand. The EM-10 has a center
green light, other wise ... . Do to the nature of the work I
do I've used my EM only a little.
That 0 to 100 dial is gain control. In a manner it indicates the
light level striking the sensor. That's it, no units of anything.
That light level is to be duplicated when ever going from one
degree of enlargment to another. Ilford SUGGESTS making a
good 8 x 10 having metered a thin area of the negative.
Take note of the dial setting. All things being equal an
increase in print size will require a faster stop and/or
more time. You've only one option, open up the
lens until your meter shows no light.
IIRC, my meter is close to 0 with thin areas and moves
up the scale as negative density increases; the gain
control. The whole thing is about as simple as the
old center the needle camera exposure meters.
As for position, I think it not important as long as
one is consistent. You're M-1, though, is not a EM-10.
All in all there is some technique and method
to learn. Dan
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For my use, I try to get it in direct line with the lens. I agree that if you are consistent with the position, it will be a consistent reading also, but for me, underneath the lens is it. Its easier to find the direct line consistently, rather than off to the sides.
Originally Posted by mhv
Once the LEDs are off, you have one of two situations.
(1) If you are just starting off in the calibration phase, you now have a number as a reference from the dial, for that particular situation (say 8x10 enlarger metered off the the fleshtone ... say metered between the eyes). You can set up as many calibration points as you wish. Just remember to record the number for each point you choose. On the other hand ...
(2) You already have it calibrated already (for example again the fleshtone, and lets assume, for example, the dial reads 25). Here, the LEDs says you now have a proper aperture to get a properly exposed print. You can raise the head up or down and by using the same dial setting on the meter, you can get a good exposure for any size of print.
If say you calibrated for an 18% grey area, just set the meter to the dial number calibrated (for example, say 20) for your 18% grey, and then meter on your grey area in the neg. That's it.
The meter is just an extension of your eyes. Its just makes it easier to estimate exposures with changing magnification and apertures. A really simple item electronically, but saves me alot of time. Enjoy and play
I was just wondering, for metering how do you position the
Originally Posted by Canuck
negative for a center reading of an area of interest? Dan
I just make sure that what I am metering, the neg is shifted and area is centred on my easel that is close to middle as possible. Meter and then recompose. For most of my own work, I use the edge metering that that once I get a base exposure for max black, I can then adjust exposure by eye.
Originally Posted by dancqu
I have an EM 10. I have a Durst S45 enlarger. It requires me to insert the negative carrier front to back. It has a lens turret that allows me to move my lens laterally. Therefore I have much flexibility to position a spot from the negative on the lens axis.
Claire (Ms Anne Thrope is in the darkroom)