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Thread: 45MCRX LED light source with condensers vs diffusion cold light.

  1. #1

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    45MCRX LED light source with condensers vs diffusion cold light.

    I recently refurbished my Beseler 45MCRX enlarger and went back to using condensers instead of the Zone vi cold light. I tried printing the other night and hated my experience.... I mean control wise. I know this isnt very scientific but its what i offer from observation using the tools I have.

    Im a bit confused about light sources. The standard bulb in the condenser head was an opal bulb marked /211 125V 75Watts. I read the color temp of this bulb with a Gossen Sixticolor meter, it read 2800K. And for a 75W bulb, it sure doesnt seem very bright, it looked more like a 40Watt.

    My Zone VI Cold light head read an astonishing 7800K. I have no idea what the wattage is, but it seems to my eye the same as a 60W bulb.

    Im switching to LED bulbs and thought since the regular 211 bulb said 75watts Id use a 60W LED bulbs. I got a few different color temps so I can choose the one that gave the best control.

    Soft White LED 2800K 60W
    Bright white LED 3000K 60W
    Daylight LED 4500K 60watt.

    I did see a bulb rated at 5000K which I will get tomorrow to try.

    I ran some VC filter tests using Ilford FB MGIV, I was very disappointing how muddy they were with the 4 (incl the 211) different bulbs.

    Am I spoiled by the cold light or am I missing something here?
    frustrated, I just may put the cold light back up.

  2. #2

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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    Perhaps this explains why the inside of the Beseler MX condenser cones are white. The inside of the Beseler CB-7 condenser cones (slightly larger) are black -- go figure.

    Here are the ANSI bulb specs -- Designation #, wattage, lumens, color temp:

    #211; 75w; 1,000; 3,000K

    #212; 150w; 2,300; 3,050K

    The bulbs have the same life expectancy -- 100 hours. My CB-7 and MXII manuals both show the 212 bulb as the "correct" bulb -- not the 211.

    Some people might prefer the 211, especially if they normally make "small" prints, use wider apertures, and/or want more time for manipulations.

    Some people might prefer the 212, especially if they normally make "large" prints, use smaller apertures, and/or use a lot of filtration.

    I have both for both reasons.

    Are you using a voltage regulator? How about VC filtration (which must have been "designed" with 3,000K in mind)? Switching to a 212 will just shorten the exposure time. It won't change the contrast/"muddiness" -- but switching away from a 3,000K bulb will have an impact of some sort. Let us know about the outcome, for sure, but remember that probably most of us use(d) 211/212-like bulbs without problems.

  3. #3

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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    Quote Originally Posted by Paul Ron View Post
    Am I spoiled by the cold light or am I missing something here? frustrated, I just may put the cold light back up.
    +1 that's what I'd do!

  4. #4

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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    the tungsten bulbs and led bulbs have shorter exposure times at the same enlargement than the cold light.

    im just bumbed out hearing so much about LEDs as the best thing since white bread. thats what inspired me to switch.

    im goint to get the higher temp leds in lower wattage to see if it makes any difference.

    im abandoning tungsten bulds.

  5. #5

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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    I hope you "don't burn your bridges behind you".

  6. #6
    jp's Avatar
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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    The advantage of LED is you can use blue or green LED to specify your contrast. If you take a white LED and filter out some spectrum you have no idea if what you need is there for the contrast you want. They do not produce light evenly across the spectrum like an incandescent bulb does. I think diffusion with multi-color LED is the most practical path for people wanting to use vc/mg paper.

  7. #7
    Randy Moe's Avatar
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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    Couple things need clearing up.

    Led's vary immensely. The design improves at least monthly.

    You state 60-watt Leds. Is that 120 VAC 60 watt actual power consumption or 60-watt equivalent. They make both, I assume you are using medium screw base E26 or 27. One is EU and one is NA. Both fit the same socket.

    Most people here that convert to LED don't use those bulbs.

    But thanks for trying. Keep trying! Document your results and show us in pics and words in an online show and tell.

    I have used panels of LEDs and LED light boxes. All documented in our DIY section. Search for it. I would have to search also. Don't use the LFPF search box, it's ridiculous. Use Google with appropriate search words.

  8. #8

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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    the LED bulbs im using are the same you use in the house... 120vac. the wattage is equivelent, actual is 8.5w.

    im sure something is going on with the actual color spectrum of leds. if i had a prism, id split out the color bands to compare... but thats for another rainy day.

    so far, even with the tunhgsten, im not happy at all.

    im looking into the multicolor LED vc heads now.... but that good ole cold light is coming back on tonight.

  9. #9
    Randy Moe's Avatar
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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    Quote Originally Posted by Paul Ron View Post
    the LED bulbs im using are the same you use in the house... 120vac. the wattage is equivelent, actual is 8.5w.

    im sure something is going on with the actual color spectrum of leds. if i had a prism, id split out the color bands to compare... but thats for another rainy day.

    so far, even with the tunhgsten, im not happy at all.

    im looking into the multicolor LED vc heads now.... but that good ole cold light is coming back on tonight.
    You can use a CD or DVD as a prism. You may find the spectrum of your bulb online.

    Are you sure that bulb is powerful enough to replace a 150-watt tungsten.

    At Lowes yesterday there was a new LED display with 4 different color temp LEDs of the same brand and size in boxes with paint chips to show what was happening. Almost like the paint dept.

    Sounds like you know what you are doing. Sorry to intrude.

  10. #10

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    Re: 45MCRX LED light source with condensers vs diffusion cold light.

    If your main problem is image tone flatness, the main problem might just be elsewhere than in your enlarger system (like cold or exhausted developer, old paper, etc), or if in the head, there are different focus points for the lamp to condenser distance where the light might seem even, but does not focus the direct rays correctly but can behave like an even diffusion source at a different point... The correct lamp to condenser distance is critical!!! (But there are condenser systems that combine these two points to give a composite % of these for a printing light effect...)

    Your old frosted bulb has a "hot spot" about 3/4" dia, that is in the spot that is centered and distance from condenser is constant and critical, but closer/further produces a different "bloom" of light on the negative, so the LED will have to replicate this point... I have placed color head diffusers at this point over condensers and have had excellent results, but not tried smaller point sources, but a normal to larger "hot spot" works well... Good condenser focus, (with a little diffusion added) works well with color or B/W... (Having great amounts of off-axis light adds to the diffusion "effect", but there might be a "too much" point...)

    The other less related effect you might see is the white LED has a much expanded output spectrum than different hot lamps (as hot lamps produce mostly IR & red end spectrum output), but there might be a strong peak in green that will expose a much greater portion of the flatter green sensitive emulsion on MG papers... But expect different curves with LED + MG filter values as the old curves were engineered for tungsten sources, so expect much different filter steps...

    But the great part is that a white LED might look much dimmer to the eyeball, but with much more B/G end of the spectrum output, this will be much brighter on this end than the old hot light output (maybe giving shorter exposures)...

    Put the old 212 bulb back in, measure centering, bulb height, and condenser distances, do some contrast tests, and see if you can maybe find some issues with your contrasts before the LED conversion goes back in...

    Good luck, and HNY to everyone!!!

    Steve K

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