complete newness to advanced darkroom electronics

[Discoman]

help me out here, i have never done any of this before...
my school just recently acquired a besseler pm color analyzer, really old unit. i have it set up next to the omega color enlarger, as it is the only enlarger that could make full use of the device.
how do i use it? do i have to calibrate it? what are the four dials that go from 0-100 used for?

and while i'm at it, what exactly is a densitometer used for? i hear that they are useful, but what exactly do they do? i can assume that it measures the density of the negatives, but exactly what does that do that makes these indispensable?
thanks.

[AJ Edmondson]

Calibration isn't really necessary unless you are transferring settings from another unit or trying to directly use the readings from a color analyzer. There is always a possibility that the dichroic filters have faded and may not give you the full range indicated on the dials but in most instances (I am assuming here) you are probably going to be using this in an "empirical" (trial and error) mode.
As for the densitometer, it does indeed measure optical density and is helpful in determining the relationship between exposure and development; x exposure at x time in selected developer at x temperature and x agitation yields x density (with the "x" being your chosen variables). There is also a reflection densitometer which is used for evaluating the paper characteristics.
Note that there is the possibility of replacing the dichroic filters in the event they are faded.

[AJ Edmondson]

Sorry... old-timer's syndrome kicking in again. Somehow I got the impression that you were asking about the enlarger's dichroics rather than the analyzer! The same analysis (enlarger's dials) doesn't hold true for the analyzer and, and, yes you need to calibrate it for the paper in use. In essence you make a color print with the enlarger, use the settings to balance out the analyzer (CYM and Exp) and then "read" the subsequent negative. That is only a very "general" description and you are best advised to acquire the operating instructions for the specific analyzer.

[ic-racer]

Two most useful things a densitometer will do for the film photographer:

1) Use it to measure 0.1 log d above film base + fog for a "Zone I" test (you may have to look that up if you don't know that that is) so you know how much light to give your film during exposure in the camera.

2) Use it in conjunction with a sensitometer (or some other means of creating some high-density areas on the film with a known source brightness) to find the gamma or slope or contrast index of the film so you know how long your film should be developed.

[ic-racer]

The color analyzer may, or may not help you make color prints. So, what I'd do is to first learn how to make color prints (if that is what you want to do) then any possible utility of that machine will be obvious to you.

[Discoman]

now this is all starting to make sense-i have always used trial-and-error to get my pictures the way I want.
so wait, for the analyzer, the enlarger goes to about 151 for the red (or is it magenta?) filter, and the analyzer maxes out at 100 on the setting dial. exactly how would I try to set it to read correctly with the filters on the enlarger?

i have the white dial set to real an 18% grey card as the null, so I can have a better guesstimate as to what my b/w exposure times are. is that okay to do, or is it beyond comprehension horrifying?

the analyzer is a beseler PM-not even the PM2. it's REALLY old. i'd only want to check instructions if I could find them free online-It isn't my unit, and I really don't want to buy instructions for a school machine (I am waiting on getting one)

[ic-racer]

now this is all starting to make sense-i have always used trial-and-error to get my pictures the way I want.
so wait, for the analyzer, the enlarger goes to about 151 for the red (or is it magenta?) filter, and the analyzer maxes out at 100 on the setting dial. exactly how would I try to set it to read correctly with the filters on the enlarger?

Here is a 'generic' way to use a color meter, as I don't know that meter you have.

Make a perfect print of a gray card by trial and error. Then zero all three color channels on the meter on the easel with the probe under the gray card image. The shoot a gray card at the front of each roll of film or at the start of each new project. Put the new negative with the gray card in the enlarger and then adjust the enlarger's dials to zero the meter (don't touch the meter's dials after setting them above).

After making your perfect print by trial and error, other methods of using the meter involve involve zeroing on the film base and zeroing with no film (just to the enlarger light) and zeroing to a poplular tone (skin or grass) or using a diffuser and doing an 'average' zero.

[Discoman]

okay, thanks.