Discussion in 'Film and Processing' started by danac, Oct 23, 2021.
Yeah, only a few of us were tough enough to put up with wet process.
Mulling this over, it makes me wonder why anyone designing or selling an enlarger within the last few years would even consider using anything other than LED illumination. Heat or 'warm up time' problems solved at a stroke!
I don't know what kind of bulb that Beseler Printmaker takes, but the LED equivalent of the common 75 or 150 watt opal enlarger bulb can be bought in almost any electrical or hardware store these days. There are also LED equivalents of a good many GU10 and other dichroic reflector tungsten-halogen lamps.
FWIW, I intend to remove the vibration-inducing fan in my Durst CLS-450 head and replace the lamp with a high-power COB LED. I reckon a 30 or 50 watt LED ought to replace the 250 watt T-H dichroic heater (that coincidentally produces a bit of visible light).
I also have in mind to stitch together the 180 RGB LEDs that came as a decorative strip into a colour-head panel. But that's another low-priority project to add to a long list.
Further to the above:
I see the Beseler Cadet II uses a standard PH140 75 watt incandescent lamp.
Replacing this with an LED equivalent should present no problem at all.
A quick Google turned up this - Link.
It has a European E27 base and works off 240 volts, but I'm sure that E26/120 volt versions are equally easily found.
My first enlarger, when I was young, had the 211, size of a regular light bulb. It was explained to me that they put the label (wattage and such) on the side, so it doesn't appear in the image.
The one I have now, has the PH111, which is, as you say, much smaller.
The Omega B22 has an extra, third, condenser lens that you use for 35mm, and not for larger negatives.
I suspect that without should work also for 35mm.
Current enlarging papers are so fast, I sometimes need neutral density to get reasonable times.
No such issue with most LED bulbs. So far I haven't seen a single one with printing on the opal plastic diffuser dome.
However, they do have a spectral bias toward blue-violet, so will almost certainly need a VC filtration adjustment, and might well prove 'brighter' (more actinic) than a visually similar incandescent lamp. The effective colour temperature also varies far more widely, but on the plus side should last far longer and be more consistent during its lifetime. So calibrate your exposures once and you should be good for years of use.
It seems that white (warm or cool) LED lamps have a wide variety of spectra:
white led spectrum - Google Search
in some cases, that could greatly complicate the use of VC paper and filters.
Some could be very far from the response expected for the use of filters.
I might be remembering someone asking about the spectral response of VC paper, which
could be useful figuring this out. From looking at them, you might do better with the
warm white, 2700K or so, lamps, but it looks so hard to say.
I suppose someone could make ones specifically for enlarging, and that might be
needed for the PH111 replacements. But I suspect also overpriced, relative to home
use lamps. (Many are subsidized by power producers, as it is cheaper than
building new power plants. But that probably doesn't apply here.)
But then there are WiFi controlled true RGB 'smart bulbs'. Which could easily eliminate the need for VC filters altogether and offer a wider contrast range than is easily achievable through white-light filtering.
Made with R, G, and B LEDs instead of white ones. Yes, that would do it.
And some blue is pretty far out there, so yes it might extend the range.
I suppose the signal can follow the power cable in.
And then there is contrast calibration.
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