Low times With Durst M601 & CLS 66

afrank · Apr 30, 2012

Hi all!

Been looking around the forums for this one but seems tricky.
I am getting 10-14 seconds for 6x6 prints using my Durst m601 color head CLS66 80mm lens fully stepped down, highest f-stop at 18cmx18cm.
I cant just raise the head as mentioned by some to get more exposure time, since I want those 18x18cm prints.
Can I use the color head dials to introduce colors and reduce the intensity?
Can I use some kind of DIY material to put on the filter tray? What should I avoid doing?

I want longer times to get a better chance to control the steps in control strips and be able to perform the burn & dodging the way God intended it to.

Thank you in advance~

Ian Grant · Apr 30, 2012

Yes you can use the Cyan filter as a ND filter along with Yellow and Magenta, or better still add a ND in the filter drawer. Adding 20y 20m 20c gives ND, just see what you need then adjust the M or Y to get your contrast.

Another alternative is to use a longer FL lens like a 105mm which will increase the height.

Ian

ic-racer · Apr 30, 2012

Ian Grant said:
Yes you can use the Cyan filter as a ND filter along with Yellow and Magenta,

Adding cyan filtration will remove red and will make the projected baseboard image look dimmer to your eye (which is sensitive to red) but the printing paper (which is not sensitive to red) won't respond with any difference.

If you are using graded paper, you can remove blue light by dialing in yellow filtration. A very rough guide is 30cc per 'stop' of exposure.

If I were in your situation, I'd get a ND filter and just screw it onto the threads of the enlarger lens.

Ian Grant · Apr 30, 2012

I think you entirely missed the point ic-racer, dialing in the same filtration with all 3 filters gives ND. A technique used in many colour labs is to add a set CC to each colour channel as ND filtration when times are too short.

ic-racer said:
If you are using graded paper, you can remove blue light by dialing in yellow filtration. A very rough guide is 30cc per 'stop' of exposure.

That then drops the contrast as well.

If the contrast filtration required is say 15m then adding 30 to each filter ie - 30y 45m 30c, gives a reasonably ND effect.

Ian

afrank · Apr 30, 2012

Great advice all! thanks!
Sadly my color head has a scale from 0-100, I heard most standerd color filtrations are in the range from 0-130/170? Am I wrong? Hows should I interpret 30/30/30 (standard) on my head? (0-100)?
How much is to be expected from using 50/50/50 on my cls head (with another 50/50/50 freedom range for contrast control)?

Ian Grant · Apr 30, 2012

Don't worry about the various different systems some were based on Kodak filtration and other Agfa etc look in an Ilford Multigrade datasheet they give the filtrations for the various systems.

All that matters to you is if you dial in 10y 10m 10c you get a degree of ND filtration, 20 or 30 of each is just greater ND filtration. My M601 and CLS66 is in storage (it's a spare now) or I'd tell you exactly but very roughly 10y 10m 10c should be about 1 stop and so on.

Ian

aca · Dec 19, 2019

Sorry, to bring this old thread up again. But I am monitoring a darkroom with some Durst enlargers M601/605 and a CLS 66 head, as @afrank notice the CLS66 only goes up to 100. I like to know what the Y M settings are for the filter 00-5, just as for the Durst with 170M / 130M??

Regards,

ic-racer · Dec 19, 2019

If you don't want to take the time to calibrate the head to the paper ( https://www.photrio.com/forum/threads/making-a-multigrade-calibration-table-for-color-head.42839/), some extrapolation of the data from the CLS70 manual might help. Looks like the CLS66 filters might be 3/5ths lower in number than Kodak. So, 100 on the CLS66 might be the same as 160 in the Kodak scale.

koraks · Dec 30, 2019

You could try to measure the total attenuation of both heads with their filters maxed out. This will give insight into the opacity of the filters (combined) compared to each other, which can be a starting point of translating the values of the filters between both heads.
When doing some measurements on my Durst M605 color head, I noticed some irregularities across the filter scales suggesting that the attenuation of the filters is not perfectly correlated (exponentially) with the filter numbers on the head. The thread linked to above suggests that a relationship such as "30cc equates to 0.3logD" would hold true, but I could not confirm this with my M605 head, which seemed to exhibit some non-linearities. I can't tell if this is due to misalignment in the filter movement mechanism or if it is inherent to the design of the filter chamber; I did not open it up to find out.

Low times With Durst M601 & CLS 66

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