Durst 1000 - Blue filter

Good point. I was picturing a really blue looking filter but perhaps it's just a slight tint.

OTOH if the filter is a colour conversion filter (i.e. a KB3 or so) the former user might have tried to enhance contrast. A frosted bulb with 150W says nothing about the colour temperature of the light; maybe it's not a dedicated bulb for enlargers and the spectrum is simply to warm.

No bulb is a Phillips Photocrescenta PF 605, filter is pale blue not unlike a 82C filter. It not heat glass its tape directly to the top condenser.

Obviously there are thousands of irrational reasons the filter could be there. If you are interested in some rational reasons, I can suggest the enlarger may have been used as a sensitometer.

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Originally Posted by SMBooth

No bulb is a Phillips Photocrescenta PF 605, filter is pale blue not unlike a 82C filter. It not heat glass its tape directly to the top condenser.

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My understanding is you're not kitted out for colour printing (correct me if I'm wrong), but maybe the filter was to provide a slightly cooler light to the warmer/reddish lamp? Much the same as you'd use an 82 A-B-C filter to cool down an overly red scene. Another theory is to correct for visual colour deficiency ("colour blindness"), much the same as a few people where blue-tinted glasses, others still wear rose-tinted... there are likely thousands of reasons.

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Originally Posted by munz6869

I have a blue filter accessory for my Grain focuser, and folks have often commented how sharp my prints are... Of course I have never ever used the thing (and why would I? It just makes everything annoyingly darker!).

Marc!

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My experience as well.

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Originally Posted by SMBooth

No bulb is a Phillips Photocrescenta PF 605, filter is pale blue not unlike a 82C filter. It not heat glass its tape directly to the top condenser.

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The bulb seems to be the correct one. The fact that the filter is taped to the condensor shows that it was not intended by DURST. Just remove it.

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Originally Posted by munz6869

I have a blue filter accessory for my Grain focuser, and folks have often commented how sharp my prints are... Of course I have never ever used the thing (and why would I? It just makes everything annoyingly darker!).

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Gene Nocon recommended the blue filter in his book Darkroom Printing. He suggested that it was better to focus using the same colour of light which the paper is sensitive too.

It doesn't matter if the light is filtered at the source or at the grain focusing device but I would remove it from the enlarger to make an actual print.


Steve.

please report your findings. i would be surprisedif it does anything but reduce light intensity.

Did a test using some ilford RC paper, grade 2.5 filter, 25 sec exposure each with the blue filter in and out, really not any different. I think you are right Ralph.