AnalyserPro calibration for Forte polygrade V FB

[grred]

Hi!

Just bought from bhphoto enough supply of Forte paper to last me at least an year. I am using AnalyserPro with Durst enlarger with colour head. My setup is calibrated for Agfa paper. I remember i burnt a lot of paper when i was calibrating my setup for my now defunct favorite paper. Now i am in the process of switching to my second favorite paper "Forte polygrade V FB".

With the cost of paper gone up drastically (I have to buy most of the stuff by post as it is almost impossible to get b&w paper where i stay) i was wondering if someone can share their calibration setting for Forte paper using a setup similar to mine. Which i can use as a starting point to save some paper.

Thanks a million in advance
gred

 

[grred]

It is almost 2 weeks since i have posted above query. Lot happened since than.... few nights in darkroom... lots of precious paper burnt for a good cause. The results are quite disappointing. Forte polygrade V paper's contrast range does not go beyond Grade 2 on my Durst M605 enlarger with colour head. This is a real problem as i print most of my negatives in the range of 2.5 to 3. Ilford MG4 FB barely goes up to grade 3. I am not able to figure out what i am doing wrong. Is there a chance that enlarger dichroic filters faded in my 10 years old enlarger? if this is the case can these filters be changed?

 

[Bruce Osgood]

I can't help you directly but you could contact Richard at RH Designs, they are one of the sponsors of APUG and can be reached at

http://www.rhdesigns.co.uk

When I've had questions about there products ( I don't have any - yet) Richard has always responded with excellent information.

 

[RH Designs]

Gred -

I missed your original posting; I'm afraid we don't have any figures for Forté papers in house. You shouldn't need to use more than a couple of 10x8 sheets for a full calibration. Alternatively we offer a calibration service, or you could try our new calibration kit if you don't already have one.

The main thing to remember is to get the exposure correction right first, based on the highlights, before attempting contrast calibration.

Dichroic filters don't generally fade, but you might find the filter mechanism in your enlarger needs attention. I seem to recall some years ago a friend of mine having a similar problem with a Durst colour head which was traced to the filters not being moved into the light path correctly. You should certainly get up to grade 4.5 with Ilford paper from that head; if you cannot, I suggest you have the head checked before going any further with calibration.

Regards
Richard

 

[grred]

Thanks a lot Bruce and Richard!

I am using stouffer step wedge for calibration. I guess i have to get my Durst head checked first. Also, hoping to get my Analyser Pro upgraded soon

Gred

 

[Dave Miller]

My Durst enlargers have a White Light Lever that moves the filters out of the light-path to give a white light for focusing. It sound like yours may not be working correctly. If you set one of the filters to maximum, then operate the lever you should see the change in light colour. If it doesn't work you will be printing under white light at around grade 2.

 

[Dave Miller]

I should also have said that it is most unlikely that your filters have faded in 10 years, my enlargers are nearer to 25 years old and still give the full grade range.

 

[RH Designs]

I should also have said that it is most unlikely that your filters have faded in 10 years, my enlargers are nearer to 25 years old and still give the full grade range.

Same goes for my LPL7700. I think dichroic filters are like polarisers inasmuch as it's an inherent characteristic of the way they're made rather than the use of a dye or pigment, and therefore they don't "fade" as such. Check for free movement of the filter mechanism - I recently took the oil can to my LPL which made everything work a lot more smoothly. But be very sparing - you don't want oil drips on the diffuser or lens.

Regards
Richard

 

[leeturner]

As Dave says sometimes the filters can stick and not return into the light path. I've got two colour heads for the Mod70 and if I wind the filter a bit too much (e.g. just past 170) and switch the lever to "out", which is the white light setting, when I reset the lever to "in" the filter doesn't drop into the light path. It's the same on both heads and by just turning the filter control a touch the filter drops down.

 

[mongo141]

As Dave says sometimes the filters can stick and not return into the light path. I've got two colour heads for the Mod70 and if I wind the filter a bit too much (e.g. just past 170) and switch the lever to "out", which is the white light setting, when I reset the lever to "in" the filter doesn't drop into the light path. It's the same on both heads and by just turning the filter control a touch the filter drops down.

I had the same problem with a New Beseler 23CIII W/ a VC Head. and had to redo the calibration for the paper I was using (Kentmere VCRC) since then the Zonemaster II has worked flawlessly and has turned out to be some of the best money I ever spent. I have the corrected Calibration figures if any one wants them. Regards, Dave

 

[grred]

Thanks a lot for all hints!

I have called my friendly local photo doctor. He gave me some diagnostic steps to identify the problem. Most of it are already mentioned in above responses.

1. Filter in out lever to check change in the light colour.
Result: Working as supposed to be.

2. Clean movement of filter in light path: Result: colour seems to be changing gradually but there i no way to check if it is changing at the rate is should be.

3. check bulb:
Result: found a decoration type halogen lamp instead of photo bulb. I guess previous owner wanted to save some money. Changed it to osram 100watt photo bulb.

FINALLY:
Got a box of fresh ilford VC paper. Did step wedge prints of all grades. Now i see grade from 4.5 to 0 (RN: 70 to 145). GREAT!

opened fresh Forte polygrade V fb paper order from BHphoto in December 05. Result.... I still see grade from barely 2 to 00 (RN: 175 to 115). Surprisingly with no filter in light path i get grade 1 but with magenta-40 i get grade 0.5.

I can leave with grade 2 contrast but i need to understand why this is happening. Is the paper not good? or worse is it fogged slightly?

Thanks
Gred

 

[martin@jangowski.de]

I can leave with grade 2 contrast but i need to understand why this is happening. Is the paper not good? or worse is it fogged slightly?

Did you check your darkroom illumination? Fogging by the safelight would easily explain your results.

Martin

 

[L Gebhardt]

Do you have any under the lens filters you can use to test with? See what range you get with those and white light. When I calibrated Forte Polygrade V with my Analyser 500 (for the Ilford 500 head) I got about grade 3.5 to 0 (150 to 69).

 

[grred]

I am using red LED safelight. When i built the safe light i did test it for fogging with Ilford and Agfa papers. I found it was quite safe. May be i need to check it with forte to be sure.

I also have under the lens ilford filters. I'll test with them today and see it it makes any difference. Thanks again for suggestions

Gred