Colour analyser for B&W printing

[xwhatsit]

Hello,

I've got a Durst CNA-200 colour analyser I picked up for next to nothing. I think I've mostly figured it out, I've never used a colour meter before but it seems typical from what I can figure out from searching -- there's a knob on the front with a seconds readout, a Y/M/C selector, and there's three gangs of trimpots with a selector, which is presumably for different types of paper or something.

I want to use it for B&W. I hear some meters have a Density channel in addition to the Yellow, Magenta and Cyan, but this doesn't. My question is, given that I'm using VC paper, is it the cyan channel I should be using? Will the fact that it's only reading cyan light play tricks on me when I change contrast filters?

If the answer is standardising on a grade 2 filter or something while I measure things, then so be it.

If I'm going to use it for printing, I assume I should use it for measuring the brightest highlights? Then expose for the seconds the meter will read? And the contrast filters will therefore adjust the shadows.

Thanks for any assistance!

 

[Mike Wilde]

I don't know your analyser, but generically:

Some analysers did colour selection by changing a dial on the photomultiplier tube probe assembly. This dial changed the electrical setting, and also moved a different filter under the aperture that admitted the light to be measured to the phototmultipier tube of light sensitive solid state device.

Other analysers had an auxilliary filter that went over the lens, so that both the filter on the lens and electrical switch on the analyser needed to be moved independently.

You could use what you have to meter the unfiltered negative (on any chanell) to calibrate and then determine the density of the densest portion that you want light (not fully white) tones to print from. Then put in an ilford MG filter, which all have the same neutrual density (except the hardest ones) to decide what contrrast range you want (i.e when you stop getting information other than full blacks) from the thinner areas of the negative.

 

[ic-racer]

You can use the Y and M channels to compare various color heads. You can also correlate your findings with step wedge exposures on multigrade paper.
The density channel can be used as an enlarging meter. Since you don't have that, you can use any of the channels since the calibration and metering needs to be done with white light. (as Mike pointed out above).
If you want to use the meter for estimating print exposure, there are a myriad of ways to calibrate it from lowest negative density, to mid density, to skin density, to grass density, to film base density, to enlarger intensity without the negative, to diffused overall density, etc. Make sure you don't have any filtration on board (white light only) when calibrating it or using it to get estimate the exposure.

If you are thinking about metering through the filtration...good luck! You might spend months trying to get that to work because of the somewhat unpredictable way paper sensitivity changes with contrast change. I suspect if it [ie metering through the filtration] were easily doable, it would be on Nicholas Lindan's site.

I use my color meter mostly as a testing tool to ensure the enlargers are performing well in terms of light output, evenness of exposure and color and to get the slope of the CC vs density curve for a particular head in anticipation of creating a mixed filtration multigrade printing table. (there was a url link here which no longer exists)

 

[xwhatsit]

Thanks for the help everybody! Well that's easy enough, I'll just pull the filter drawer out when metering. That's good, because the cyan channel seems a bit finicky (meter jumps around all over the place). It moves colour filters over the sensor. I don't know why it jumps around, maybe bad connections on the wiring through the pot banks for the cyan channel. Will pull it apart after work.

Cheers! Everything is a lot clearer now.