Analyser Pro calibration

[etn]

Folks,

Apologies if this has already been discussed before - if it has been, I overlooked the thread.

I am trying to calibrate my new RH Analyser Pro (Fantastic machine, btw!) and am stuck at the very first step. For reproducibility I "reset all variables": new light bulb (of which I have a second one of the same make & model), new developer, etc. I also use the lens and condenser I use for all my printing i.e. Rodagon 90 and Bimacon 75. I use the same for both 35mm and 6x6. Enlarger is an M805. Light bulb is a "Dr Fischer 150W Opallampe" available at Fotoimpex, 150W being the default for the M805.

Even uncalibrated, the Analyser has provided good and consistent results with the setup described above, so it's just a matter of fine-tuning. Measurements before printing are done without any MultiGrade filter, then a filter is installed after the indication of the Analyser, as indicated in the user's manual (unless I misunderstood it!).

Question 1. Is my understanding correct that:
a. Calibration is done without any negative in the neg holder
b. Before doing the speed test strips, a measurement is done with the Analyser. This measurement is done without any MG filter (as for normal prints). The measurement should bring an exposure time between 10 and 20 seconds.
c. Then, a series of test strips based on the exposure determined in (b) are done with each grade filter.
(d. Side note, only grades 00, 0, 1, 2, 3, 4, 5 are measured, although the Analyser supports intermediate grade values as well)

Question 2. Even with the head in its highest position and the lens at f/22, the measured exposure is 2.88 seconds - way too short to make a test strip. (the Analyser wouldn't let me do it even if I wanted to).
What shall I do? Not sure an ND filter is a good thing here... shall I make a "neutral grey" negative and use that for calibration? Or shall I dump the 150W bulb and use 75W instead? (but the 150W has been working great as soon as a negative is in place). Any advice?

Thanks!

ETN

 

[rpavich]

Folks,

Apologies if this has already been discussed before - if it has been, I overlooked the thread.

I am trying to calibrate my new RH Analyser Pro (Fantastic machine, btw!) and am stuck at the very first step. For reproducibility I "reset all variables": new light bulb (of which I have a second one of the same make & model), new developer, etc. I also use the lens and condenser I use for all my printing i.e. Rodagon 90 and Bimacon 75. I use the same for both 35mm and 6x6. Enlarger is an M805. Light bulb is a "Dr Fischer 150W Opallampe" available at Fotoimpex, 150W being the default for the M805.

Even uncalibrated, the Analyser has provided good and consistent results with the setup described above, so it's just a matter of fine-tuning.

True

Measurements before printing are done without any MultiGrade filter, then a filter is installed after the indication of the Analyser, as indicated in the user's manual (unless I misunderstood it!).

Yes, thats true too

Question 1. Is my understanding correct that:
a. Calibration is done without any negative in the neg holder

True

b. Before doing the speed test strips, a measurement is done with the Analyser. This measurement is done without any MG filter (as for normal prints). The measurement should bring an exposure time between 10 and 20 seconds.

True also

c. Then, a series of test strips based on the exposure determined in (b) are done with each grade filter.

(d. Side note, only grades 00, 0, 1, 2, 3, 4, 5 are measured, although the Analyser supports intermediate grade values as well)

True

Question 2. Even with the head in its highest position and the lens at f/22, the measured exposure is 2.88 seconds - way too short to make a test strip. (the Analyser wouldn't let me do it even if I wanted to).
What shall I do? Not sure an ND filter is a good thing here... shall I make a "neutral grey" negative and use that for calibration? Or shall I dump the 150W bulb and use 75W instead? (but the 150W has been working great as soon as a negative is in place). Any advice?

Thanks!

ETN

You need to slide a piece of ND filter in the filter slot to bring the light level down so that the length of test is in the ballpark.
B&H sells the Rosco brand sheets of ND film. Just cut one to fit. Stack two if necessary. When you get your results, youll just take that into account when inputting how much to offset from the default times.

Here are the details:

Rosco ROE209S
E-Colour #209 .3 Neutral Density (21x24" Sheet)

 

[rpavich]

By the way, the RH Designs staff are more than willing to answer questions, they helped with my problems setting up also.

 

[rpavich]

Did you crank the head up as far as it will go before testing?

You want it as far away as you can get it to lengthen the time

 

[etn]

Hello Rpavich,

Thank you. Very helpful. The last thing I don't understand is the necessity of taking the ND filter into account into the offset calculation. Differences in luminosity due to lens f/stop or head position (and yes, I cranked it all the way up, btw) are not taken into consideration either. Giving second thoughts to the entire process since yesterday, what we are calibrating here is the luminosity value measured by the Analyser, vs certain tones on the paper. So everything on the enlarger side is theoretically out of the equation. But other variables such as paper, developer etc are not. Does this make sense?

If this is true, we should not take the ND filter into consideration, as long as it is in place BEFORE doing the initial measurement, what do you think?

As a result, the ND filter does not need to be precise to a known density. I will try to do my own filter by photographying an evenly-lit white wall at different exposures levels. I'll use that for a first calibration round and analyze the results. Will report my findings here.

Thanks & a good new year 2017!

 

[rpavich]

Hello Rpavich,

Thank you. Very helpful. The last thing I don't understand is the necessity of taking the ND filter into account into the offset calculation. Differences in luminosity due to lens f/stop or head position (and yes, I cranked it all the way up, btw) are not taken into consideration either. Giving second thoughts to the entire process since yesterday, what we are calibrating here is the luminosity value measured by the Analyser, vs certain tones on the paper. So everything on the enlarger side is theoretically out of the equation. But other variables such as paper, developer etc are not. Does this make sense?

If this is true, we should not take the ND filter into consideration, as long as it is in place BEFORE doing the initial measurement, what do you think?

As a result, the ND filter does not need to be precise to a known density. I will try to do my own filter by photographying an evenly-lit white wall at different exposures levels. I'll use that for a first calibration round and analyze the results. Will report my findings here.

Thanks & a good new year 2017!

Well...I typed that from memory and you are correct. Whatever you do to reduce the light doesn't factor in. The directions also said you can use a piece of unexposed but processed film leader or ND filter or even dialing in equal amounts of Y-C-B if you are using a color enlarger to reduce the light level to be correct in length.
It's really easy once you've done it a few times though there are a few places to trip you up. Don't ask me how I know.
To me, it's easier to write down the steps in big bold print so I can go from one step to the next without thinking.
You know:
1.) Raise enlarger head.
2.) Close aperture to f/22
3.) Clear analyser pro
4.) Make sure that the adjustment increments are on 1/4 stop.
5.) Make sure no filter is in the filter slot.
6.) Take light reading.
7.) Put filter in slot.
8.) Press and hold the 1st button until the test mode is entered.
9.) Put strip of paper into easel.
10.) Push exposure button while leaving entire strip uncovered.
11.) Mask 1" of strip and push exposure button again.
12.) Continue to mask 1" off and push exposure button a total of 6 times.
13.) Develop and dry strip.
14.) Mark strip with what filter was used and what paper it is.
15.) Repeat for other filter grades.

 

[rpavich]

If you are impatient, you can also just do the calibration for the #2 filter and use that value on all of the steps (it's not as precise but it's good in a pinch and will be pretty close.)

 

[etn]

Thanks. This helps. Will do the complete calibration for all 7 strips, shouldn't take that much longer than just for grade 2.
Will do all the exposures at once, then all the developing.

Your check list is also very helpful. I made my own after reading the manual, it's great to be able to compare it with yours!

Cheers
Etienne

 

[mr rusty]

don't overlook thatthere are how-to videos on the website http://www.rhdesigns.co.uk/darkroom/html/demo_videos.html

 

[etn]

Yes, you bet I watched those videos countless times. I also studied the manual and gave all this more thought since I posted the thread.

In the meantime, I also created a set of "ND filters" (nothing fancy, just took a series of pictures of an evenly lit white wall at 1-EV spaced shutter speeds and the lens defocused. Worked surprisingly well I have to say!) Will use this to do the calibration as soon as I can plan a 3-hr long darkroom session, hopefully this weekend.

 

[ac12]

The Durst enlargers can be rather FAST printers with the 150w bulb.
I had a 150w in my M600, but the exposure times were too fast (less than 5 seconds). So I dropped down to the 75w bulb (the lowest wattage bulb that I could find), and even that is many times too fast. I would really like a 25w bulb, to get the exposure in the 15-20 second range. But the bright image is EASY to focus on.