Durst M605c: filter broken?!

Discussion in 'Enlarging' started by SoulSurround, Oct 23, 2005.

  1. SoulSurround

    SoulSurround Member

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    L.S.,

    Trying to figure out why my printing times (2 seconds for an 8x10inch print at f/11) were so short. I compared my Durst M605c to my sisters' enlarger, who owns the same model. It struck me that the amount of Yellow and Magenta were far more visible on her groundplate than on mine (and yes I did check that the filters were swung in the light-path; there is some visible yellow and magenta filtration but simply not as much as in my sister's enlarger).

    Did anyone have this problem aswell? Is it possible to take the colour-head apart and solve the porblem? Just thought I'd ask, before I break it!

    Thanks in advance,
    Jeroen
     
  2. John Koehrer

    John Koehrer Subscriber

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    Jeroen,
    Not having a Dusrt enlarger I can't speak from experience on that model.
    However I've got a Focomat v35 & two color modules. They're not that difficult to dis/re assemble. Would it be possible to compare the two modules side by side & see if there are any alignment or adjustment points.
     
  3. SoulSurround

    SoulSurround Member

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    That was indeed my idea, but hopefully someone will be able to tell me whether it is "safe" to disassemble the head myself. I know for example that, with the Leitz V35, you should be very carefull disassembling the mount that holds the focotar as a spring will pop out and is very small and hard to place back into the place it belonged. So before I get such a surpise... I hope that someone can tell me he/she disassembled the Durst M605c head without any stuff breaking or popping out :smile:.

    Thanks for your contribution though!
    Jeroen
     
  4. psvensson

    psvensson Member

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    On my Durst M605, there's an additional magenta filter that can be flipped in just in front of the bulb. It's controlled by a switch at the rear of the head. Perhaps it's engaged on your sister machine and not on yours? It's just a wild guess - it doesn't really sound like this fits your problem.

    The M605 head is not that hard to take apart. I took it apart to find out that the cyan filter was stuck. I didn't manage to fix that, but putting the head back together wasn't hard.
     
  5. resummerfield

    resummerfield Subscriber

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    I’ve disassembled both the Durst CLS1840 and the CLS501, and both were very similar and easy. I would expect the 605 to be similar as well. I would check to see if the dichro filters are completely extended at max values, and then completely retracted at “0” values. Also check that the diffusers below the dichro filters are in place. And finally, are you using the correct bulb? 2 seconds at f11 for an 8x10 is way too short.
     
  6. bon-jip

    bon-jip Member

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    I have a pdf manual for the M605 if you are interested. It says the supplementory filtre that can be swung into the light path via the knob behind the head is "equivalant to equal parts 40 yellow and 40 magenta in the colour mixing head"
    It could acount for the extra colour and longer times, but like psvensson said, it may not be your problem and is just a guess.
     
  7. SoulSurround

    SoulSurround Member

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    Thanks! That is re-assuring. However, I found another way to 'solve' the problem. I sent the head to 'Heiland':

    http://www.heilandelectronic.de/html/english/products/splitgrade_main.htm

    to have a splitgrade module installed (I already own a controller for another enlarger, hence this step was cost-efficient).

    By the way, my sisters colour head does not have an additonal magenta filter, and mine has (apparently mine is older as I was told).
    Thanks again,
    Jeroen
     
  8. SoulSurround

    SoulSurround Member

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    I am using the correct (100W, 12V) bulb. I can't check the filters anymore as they will be 'ripped out of the head' soon (see post above this one). Thanks for your contribution though!
    Jeroen
     
  9. SoulSurround

    SoulSurround Member

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    Thanks, I am VERY interested in the manual, I will PM you with my e-mail address. However, it sounds a bit silly that the supplementory filter swings in both 40 yellow AND 40 magenta... these values will compensate eachother, no?! I thought the filter was for extra magenta only!
    Thanks again, Jeroen
     
  10. bon-jip

    bon-jip Member

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    As you'll soon see it says in the manual that the filtre is to be used "when the maximum setting of 130 is insufficent" I have never used it but it would be interesting to see if you could squeeze a higher contrast out of a print, even with the extra 40 in yellow. I actually have a print in mind that I might have to try it on now that my curiosity has been sparked.

    Jason.
     
  11. pentaxuser

    pentaxuser Subscriber

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    I too own a Durst M605 and found that for colour printing from negs I was getting very short exposure times. I have a Paterson colour analyser and even at f16 which was the smallest f stop on my 50mm lens I was getting exposure times which were less than the analyser exposure dial was calibrated for. The exposure dial stops at about 4 seconds. So at F11 which is one stop bigger then 2 seconds is completely consistent with my experience.

    My solution was to purchase a 75 watt bulb which increases most exposures to between 5 and 8 seconds at f11 and gives room for dodging and burning if required by moving to f16.

    The alternative which was suggested to me on APUG and which I also know will work because I have tried it, is to dial in cyan and increase yellow and magenta by the same amounts thus giving a neutral density effect to increase exposure. So if the correct balance is 45Y and 50M and dialling in 10 C gives a reasonable exposure then increase Y and M by 10.

    I know Durst specify a 100W bulb which raises the question of why it specified this size and not 75W. I have no answer for this except to say that I have never experienced very short exposures with B&W negs so maybe Durst thought that most of the time a 100W bulb would be OK. It is OK for 6x6 negs and a 80mm lens which anyway goes to f22 and also Ok for B&W negs.

    Hope this helps

    Pentaxuser
     
  12. SoulSurround

    SoulSurround Member

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    That is odd, because I get those time with 6x6 B&W negatives! I did also get another very helpful tip: screw a ND filter in the enlarger's lens. I don't really like using very small apertures (16 - 22) by the way as the lens performance drops then... don't you have that experience?

    Thanks pentaxuser!
    Jeroen
     
  13. pentaxuser

    pentaxuser Subscriber

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    Interesting points you make about lens performance at small apertures. I too have heard that the middle range is better. The usual procedure in the photographic manuals seems to be focus at the biggest aperture and then expose at two or three stops down. Well on my 50mm lens this would be f5.6 or f8 and I would have ridiculously short exposures at f5.6. Most of my prints are at f11 and some at f16.

    I must try to do a print at f16 then the same print at say f11 then f8 then f5.6 to see what difference I can see. Hopefully provided I dial in enough cyan I should be able to get reasonable exposures. Even 10C made quite a difference.

    I suspect that at my usual print size of 5x8 and 8x10 I probably couldn't see any difference but it's worth a try.

    My feeling is that unless there is a real difference in quality then it's not worth the effort to dial in ND unless I need to increase exposure even at f16.

    I'd be very happy to hear from our members about the scientific truth of enlarger lens performance at small f stops and more importantly its practical effect on print quality. The great thing about APUG is that we have members with more experience than I could now gain even if I am still alive and in the darkroom until I am about 80.
     
  14. SoulSurround

    SoulSurround Member

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    Boohoo

    Mmm, just got back the head from Heiland, and although it works like a charm... my printing times are still way too short.

    Details:
    * 6.7x6.7 inch print
    * 100W 12V lamp (Osram HLX XENOPHOT)
    * Schneider Componon-S 80mm f/4 lens (stopped down to F/8)
    * Kentmere VC Fineprint (Finegrain) paper

    Time is just above 1 (!!!) second and the heiland splitgrade selects grade 3.6 (the contrast it measured was 0.8).

    Just to be clear, we are talking about a black and white 6x6cm negative (Kodak TRI-X 400).

    I am clueless :-(
    Jeroen
     
  15. resummerfield

    resummerfield Subscriber

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    I’m just guessing here…… Your M605 must have a transformer to set the bulb voltage to 12v. Is it set-up for the correct mains input voltage?
     
  16. SoulSurround

    SoulSurround Member

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    I just measured the voltage over the lamp, it varies between 11.6 and 11.7 Volts which seems reasonable... unfortunately :-(.
     
  17. pentaxuser

    pentaxuser Subscriber

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    There seems to be no obvious reasons for these very short exposures. So now is the time for possibly ridiculous suggestions. Here's one. Most of my shots are outside in good light but I sometimes take shots inside churches where the light is poor. In order to be able to handhold the camera I tend to underexpose which results in thinner negatives. These require me to dial in neutral density with the cyan dial even at f16 and a 75watt lamp. They print OK so if anyone looked at the print it would not be obvious that the negative is thin but when compared to the other negs there is a difference.

    Could it be that your negs are either underexposed or underdeveloped?

    Are you processing your own negs? If not try and compare your short exposure negs with others you know to be fully exposed and developed to see if there is a difference.

    Just a longshot. I hope there are others whose diagnostic skills and knowledge are better than mine and who can get to the bottom of your problem.

    Pentaxuser

    Pentaxuser
     
  18. SoulSurround

    SoulSurround Member

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    The negative I used was a tad underdeveloped. But I did determine the time I would need to get 'maximum black' in the print and that comes down to about 2.5 seconds at f/8.

    I think I have no other option than to buy a greyfilter that filters out two stops. Now the best way would be to place a filter in the head itself. But then I can only place it directly after the lamp, which gets very hot:

    Are there people that can advise me whether there are greyfilters that can cope with heat? Maybe ones that are used with (non-flash) studio-lighting?

    The other option is to screw a filter on my Componon-S... which will hopefully not degrade the quality visibly.

    Thanks in advance for any suggestions!
    Jeroen
     
  19. pentaxuser

    pentaxuser Subscriber

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    At the risk of sounding like someone who has recently appeared again on APUG and seems to think there is only one correct way which is his way of doing things, there is an alternative to a filter which requires no additional cost.It is to use the cyan dial as if it were a ND.

    I say this because you may not have seen my earlier reply. If you haven't then please have a look. If you have seen it and decided not to try it but to use a ND filter instead then OK.

    You could close the lens by two stops from f8 to f16. This would increase the exposure from 2.5 seconds to 10 seconds. I cannot say that it wouldn't affect your print quality by using f16 but I think you'd find the quality OK. Occasionally I am able to do prints at f11 and very occasionally at f8 and when I do there seems to be no difference in quality, at least for prints which are 20cms x 25cms.

    Best of luck whichever way you go.

    Pentaxuser
     
  20. Fotohuis

    Fotohuis Member

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    We have search things out for Jeroen. These kind of things are mostly a combination of factors. The Heiland split grade is OK. This HLX100 Watt bulb seems to be on the ++ side, but can be easily changed for a same type 75 Watt bulb. Further his negative seems to be on the thin side but I will measure it later on our TRD-Z Densitometer (Heiland). The used Kentmere VC paper is very sensitive, easy for larger prints, not so easy now for this smaller prints.
    Times around 20 Seconds you will only reach on aperture 8 in combination of a high quality 0,6 ND filter (e.g. Heliopan) to prevent quality loss of the enlarger lens. Differences between F=8-11 are very small, mostly almost undetectable. Only on full aperture and the other end, 16 or 22 you can see the differences.

    We are working with Dunco II 67 enlargers. Very bright and on smaller format RA-4 prints we also have to use the 0,6 ND filter. M605/M670 and Dunco II 67 can share the same type of Osram bulbs (HLX100 or HLX75) so it must be not a big deal to solve most of Jeroens problems in combination with a ND 0,6 for his small prints.

    Best regards,

    Robert

    (Also from the Netherlands)
     
  21. SoulSurround

    SoulSurround Member

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    As I posted earlier on... there is no Cyan anymore in my enlarger head; it's been replaced by the splitgrade-head from Heiland.
    I just performed a test on the different appertures, the best opening for my Componon-S is F/11 and F/8 is also good... above or below those values, the results are not satisfying for me.
    Thanks... I have ordered a 75Watt bulb and a Heiliopan filter as Robert mentioned above. I will post my experiences with the filter once I get some results!