I am saving up to buy one in almost mint condition.
I am saving up to buy one in almost mint condition.
In the CLS 2000 manual there are two separate references of 2 Infra-Red absorbing filters between the lamp/dichroic-reflector assembly and the color Dichroic filters:
The closest I can get in terms of identifying the correct part for the filter in position 32 in this diagram, is from the Spare Parts List for the Durst HL 2501 AF…
It's the part #7, which is identified as "Heat protection filter, Code number: AA98429"
The metal frame/mechanism holding this filter in place is identical to the one in my head…
In this low quality picture, it looks like there is only one glass in that position… just like in my head…
I wonder of the possibility that maybe different generations of CLS 2000 heads (they were produced from 1977 to 1990), might have different filters in the "position 32" of the CLS 2000 manual…
By the way, there is a notable difference between the these heads:
It looks like the upper fan in the HL 2501 only blows air on the lamp/dichroic-reflector assembly alone, while in the CLS 2000 the air stream from the same fan also reaches the dichroic filters…
I would greatly appreciate any additional information on these IR filters.
I can't offer any useful information on the filters. I did not take my CLS2000 head apart that far. In fact the CLS2000 I got had never been taken apart before and was essentially untampered and in excellent shape (except for a short that I fixed).
Normally I would expect Schott KG1 as a filter in these locations. I think that was what was used on the 138S . That is relatively colourless
ic-racer,
I won't get into the "why" I had to open the head that far just yet, in order to avoid muddy the waters with information unrelated to the question at hand… once I'm done fixing the filters, I'll post some details in case it proves useful to others…
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Mark J,
Having followed your thread on the IR heat filter for the L138s, it did cross my mind that maybe the "Two heat filters" in the CLS 2000 manual might actually refer to 1 filter in 2 pieces, as is the case in your enlarger (and also in my Ilford MG500 head as well)…
That is why in my post #878 I asked other users of this head if they could remove the lamp reflector and look down towards the color filters…
If their IR filter was indeed two parts, there should be a clearly visible line were the two pieces touch in the middle…
This is quite possible. I believe that the Schott filter materials were/are only produced in a limited width, which would require fitting two filters side by side to cover the area.
I have a piece of KG3 ready to use in my head, but haven't found someone to cut the rectangular pice into two, with accurate edges yet. With only a 160W bulb, I seem to be coping OK without it.
I scanned my archives and I did not take many pictures of my CLS2000 when I was preparing it for use. Nothing that would help here.
Yes there is a difference. The older one uses a slightly higher "oben" box And a optional IR filter without the glass rods. The newer one has a slightly beter light distribution.Originally Posted by Thodoris Tzalavras
ic-racer,
I know the feeling…
When I had the head open back in January, I only took pictures of the dichroic filters…
That's why I haven't posted a picture of the filter in question from my own archive…
When I open it up again, I'll make sure to take more pictures…
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Gary,
I consider you an authority on the subject, and I hate to contradict you, but I'm relatively sure that:
The 72 x 72mm filter (in the pictures you shared in post #879 ) which goes just above the glass rod diffuser assembly, is in fact a UV filter.
The IR filter is much larger (110 x 110mm) and its position is above the CMY dichroic filters.
The position of the IR filter is such, as to protect the CMY dichroic filters from excess thermal infrared radiation, and help extend the life of the dichroic filters… It would make no sense for it to be placed below them…
Please check again this diagram, and the accompanying text:
Just inspect your own one. If there are clips and a recess for a filter under the shutter. As in the first foto that ic-racer shows.
Last edited by gary mulder; 14-Apr-2024 at 06:04.
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