RH Designs Analyser Pro calibration with densitometer and projection scale

kal800 · Dec 17, 2022

Hi,

As the new gear is coming, it has to be calibrated. This time, I'd like it to be super precise - my current settings is not as good as I would like to be.

The equipment set:

Laborator 1200 with condenser head and Ilford MG filter set
Reflective/Transmissive densitometer
Stouffer 4x5 31 steps projection scale (TP 4x5 31)

I read the procedure in manual and I understand that I should make 7 prints of a scale (the question - should I contact print them, or put a scale in a neg carriage and print on a paper?), develop, measure density of each bar and put step being 1/3 stop number on X axis, and density on logarithmic Y axis getting nice curves. This looks pretty clear for me till that moment.

It is not clear how should I process this data to get contrast value and offset that I will then put into the analyser.

Please advise

Kal800

removedacct3 · Dec 17, 2022

Hi!

If you would like to calibrate using the step wedge, then you should contact print the step wedge. The exposure time is not relevant as long as you see paper white and pitch black on a single sheet of paper. If that is the case you should measure each bar with your densitometer and do the calculations as described in the calibration manual. Make sure that your head is as high as possible to even out illumination densities.

If you do your calibration like this and you pay attention to your consistency you will get good results.

However, if you would like to improve your results you should read section 5.4 of the ZoneMaster II calibration manual: "Refining the Contrast Calibration". (I am aware that you would like to calibrate your Analyzer Pro, but I believe the exposure and contrast calibrations are alike). The entire calibration process will take considerably longer, as you should determine exposure values first with dried paper, before you can start with your contrast calibrations. This method relies on accurate exposure settings.

Please have a look and do not hesitate to make some noise in case of questions ....

https://rhdesigns.co.uk/wp-content/uploads/2020/06/Calibration-Manual2020.pdf

kal800 · Dec 17, 2022

I was referring to this calibration procedure:

https://rhdesigns.co.uk/wp-content/uploads/2020/03/pluscal.pdf

For me, it is unclear how should I calculate "Meter software constant"

peoplemerge · Dec 17, 2022

If you have not already done so, I recommend Beyond the Zone System by Phil Davis for background reading. It took me a couple of reads for it all to sink in.

removedacct3 · Dec 17, 2022

kal800 said:
I was referring to this calibration procedure:

https://rhdesigns.co.uk/wp-content/uploads/2020/03/pluscal.pdf

For me, it is unclear how should I calculate "Meter software constant"

Okay, that procedure is new to me. I have not used it yet.

From the looks of it, the meter software constant is a baked in constant value that does not need any re-calculation. For grade 4 that value is always 112 etc

Joel_L · Dec 21, 2022

I recently ordered the Zonemaster IIm and Stopclock. I think the ZM II is the same as the analyzer in the analyzer pro. I was hoping to get it before the holidays but doesn't look like that will happen. In any case, I will be going through this exercise too.

If you learn anything interesting, please post.

kal800 · Feb 5, 2023

Hi,

I'm struggling to get my Foma FB paper calibrated with condenser enlarger and cannot get any success. Long story short - head all up to the top of the column, lens stopped down do f45, G2 filter, shortest time possible - 1:15 seconds, empty neg carrier in, LED light source of 6500 K, 2450lm. All I can achieve is D0.08, I am not able to get referential D0.04 at all. Anybody ever calibrated Foma paper with condensed head?

albada · Feb 5, 2023

kal800 said:
Hi,

I'm struggling to get my Foma FB paper calibrated with condenser enlarger and cannot get any success. Long story short - head all up to the top of the column, lens stopped down do f45, G2 filter, shortest time possible - 1:15 seconds, empty neg carrier in, LED light source of 6500 K, 2450lm. All I can achieve is D0.08, I am not able to get referential D0.04 at all. Anybody ever calibrated Foma paper with condensed head?

I think you're trying to get the lowest density the paper can provide (D-min). If so, have you tried developing a piece of unexposed paper? My tests showed that the D-min of Foma RC is 0.11, so the 0.08 that you're getting for FB seems reasonable for Foma. For comparison, Ilford RC and FB measure at 0.06.

Mark

removedacct3 · Feb 6, 2023

kal800 said:
Hi,

I'm struggling to get my Foma FB paper calibrated with condenser enlarger and cannot get any success. Long story short - head all up to the top of the column, lens stopped down do f45, G2 filter, shortest time possible - 1:15 seconds, empty neg carrier in, LED light source of 6500 K, 2450lm. All I can achieve is D0.08, I am not able to get referential D0.04 at all. Anybody ever calibrated Foma paper with condensed head?

I did successfully calibrate my zonemaster with Fomabrom paper using a LED source, but I needed a ND filter to do so. That would be my advice as well, get an ND filter for your enlarger lens.

Ulrich Drolshagen · Feb 6, 2023

kal800 said:
1:15 seconds

This information seems ambiguous to me. Is it 1.15" or is it 1' 15"?

If it is really 1.15" stopped down with the head all the way up there seems to be too much light to be practically usefull in general. I'd be inclined to rework the lightsource first.

Ulrich

kal800 · Feb 6, 2023

That’s my point - if I opened up the lens two stops and lower the head to have standard enlargements, I would have to install a LF lens with shutter. I’ll start with getting weaker bulb.

removedacct3 · Aug 3, 2023

kal800 said:
I’ll start with getting weaker bulb.

Perhaps a bit late, but how did it all work out?

RH Designs Analyser Pro calibration with densitometer and projection scale

Privacy & Transparency

Privacy & Transparency