The most ideal enlarger light bulb for some?

David Lyga

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There are many out there still using enlargers taking the traditional opal PH140 or #211 bulbs. I wonder if those people are aware of a 50 cent replacement?

Today, I went to the chain "DollarTree" and bought a package of two (Sunbeam brand) LED 60W equivalent bulbs for only $1, total. Just because I was curious and had never bought an AC LED bulb before, I put one into my Meopta Axomat 5 enlarger. What I found out needs to be related to all:

>If anything, the baseboard image is even a bit more even than from the standard #211 tungsten bulb
>The life of the LED bulb is many times longer than the #211 bulb
>To my astonishment, the LED bulb is dimmable; the full strength color temp is K3000
>The LED runs far cooler than the #211. This translates to no worry about negative buckling
>Although stated as being a 60W equivalent (actual 9.5 W), the baseboard image is at least as bright as the 75W #211
>The Sunbeam website is limagehomeproducts.com

My question to you is this: Is the color spectrum for the LED bulb compatible with both VC filtration (for B&W) and CP filtration for RA4 printing in color? - David Lyga
 

MattKing

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A lot of LED bulbs have discontinuous spectra, so you need to be careful with processes that are designed for a light source like a tungsten bulb that emits continuous spectrum light.
 
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David Lyga

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I thought that this was too good to be true. We will see what others have to say, Matt. - David Lyga
 

jim10219

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Give it a try. A single LED will have a very narrow color spectrum. In fact, there's no such thing as a white LED. Most white LED's are created by either combining a blue LED with an yellowish-orange emitting phosphor or by combining blue, green, and red LED's (like an RGB monitor). The latter will probably give you a smoother color spectrum. But they tend to be more exoensive. Either may give you acceptable results with B&W printing, though you may have to adjust your times, and the filters for VC papers may need some adjustments for their calculations too.

In other words, it may work, but it might require some experimentation to work around it's peculiarities. I imagine the Lifx or Philips Hue lights would be interesting to try with all of their controls, but they're far from cheap.
 

Pieter12

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My experience with LED bulbs is they have a lag time when first lit, and an after-glow when extinguished. Some more than others, but it may be enough to mess with exposure times.
 

ic-racer

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How even is the illumination? I presume there are no words or letters on the plastic diffuser. If you have some multigrade filters you should test it and see.
 

Arklatexian

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I have been playing with some GE 60W equivalent bulbs in my enlargers. Their color temperature is approx 2800K. I have not made any enlargements yet but everything you said about your Sunbeam bulbs apply also to these GEs. I don't know if these are dimmable (haven't tried). "Heat popping" of the negative should be a thing of the past. First thing I noticed is how even the baseboard image was. If these work (and we can still get these in the future), our worries about obtaining tungsten enlarger bulbs are over. I hope! I hope! I hope!........Regards!
 
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AgX

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Only incandescant lamps yield a true continuous spectrum as being a thermal radiator. Their colour rendition is designated as Ra100.

All non-thermal radiators are tuned in by adding fluorescant/phosphorescant materials. As lighting source for colour reproduction a sours with a Ra figure in the high 90s was advised.
The household LED bulbs are at about 80.

However... for common subjects such continuous spectrum is necessary. For colour printing though only the three spectras of the negative's image dyes absorbtion and the paper's sensitizing dyes count.
 
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David Lyga

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Well we have a proper panoply of information here; some conflicting, as is appropriate. There is only one thing to do and that is to test, but I have to restate to all that I was dumbfounded by the evenness of the baseboard image and I hope that this, alone, causes some to ponder further.
One thing that I feel is certain: if you use a graded B&W paper, the spectrum CANNOT matter, as all you are doing is projecting an image that is generated from pure silver and ONLY silver.

Disagree? State why. - David Lyga
 

ic-racer

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Just contract print some step wedge images with the Ilford filters and see how the LED behaves. White LED spectrum can be all over the place, depending on how your lamp is manufactured. Or, as you suggest, print on graded paper and not worry about the LED spectrum.
Image shows color spectrum of three samples of WHITE LED, it is closer to an incandescent lamp than a high-voltage gas lamp.
 

ic-racer

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Here are Mercury and Xenon 'White' lamps (compared to incandescent; Halogen) as a comparison to the above "White" LED spectrum.
 
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David Lyga

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One question: Is an incandescent lamp 'perfect' as regards color or VC B&W printing? If not, which lamp is? - David Lyga
 

ic-racer

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BTW I do all my printing with halogen lamps; last 30 years and hope to continue into the next 30 years doing so.
 

ic-racer

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David Lyga said:
One question: Is an incandescent lamp 'perfect' as regards color or VC B&W printing? If not, which lamp is? - David Lyga
Click to expand...
Color printing materials were designed around incandescent exposure. But, as you know, color printing enlarger manufactures have adapted Xenon and arc-discharge and recently LED lamps to color printing with good success.
 

bernard_L

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What would worry me is the dip around 470nm.

(from https://en.wikipedia.org/wiki/Light-emitting_diode)
For both MGFB and MGRC papers, Ilford states that each of the three emulsions has a different amount of green sensitizing dye; no mention of sensitivity at an intermediate wavelength, like blue-green (say 500nm). So far so good.

For the FB paper, the sensitivity curve matches the text, with a dip... just at the same wavelength as the "white" LED; pre-arranged harmony?


For the RC paper, the curve has three "humps", the middle one being at approx same lambda as the dip in the LED emission.


Go figure. I would bet the emulsions are actually identical, and either one of the documents is an obsolete version, or the curves are "artist impression", (or both).

So, in the David Lyga spirit, I'd say: just test. Maybe the result will be different from incandescent. Maybe, even, it will be more eye-pleasing to some. Who knows.
 

David Brown

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I think the bottom line here is that not all led bulbs are the same. In the facility where I teach darkroom, the owner replaced the lamps in all of the Beseler 23C enlargers with leds. Worked fine for my beginners, but I was skeptical when it was time to imtroduce contrast filters. However, they appear to work fine. Or, at least well enough for our purposes. I am still skeptical that the grades are exact, but if one can get the print they wish, the all is well. As was said, test and see.

PS: I won’t be switching the lamps in my own enlargers as long as oem lamps remain available. And I have about a ten year supply.
 

MattKing

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Using fixed grade paper may or may not be a "solution". Fixed grade paper also has a range of spectral sensitivities, and it is certainly possible that a "dip" in the LED emission may correspond with that part of the spectrum to which the paper is most sensitive.
And of course, different papers may respond differently to different parts of the spectrum.
I wonder if the spectral sensitivity differs between different grades of the same paper.
 

jim10219

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David Lyga said:
One question: Is an incandescent lamp 'perfect' as regards color or VC B&W printing? If not, which lamp is? - David Lyga
Click to expand...
No lamp is going to be perfect. Even the sun doesn't put out an even spectrum, yet it's the measuring stick by which all bulbs are compared to. But incandescents, like the sun, put out a near linear spectrum. Incandescents tend to be higher in the red and infrared, and don't put out much UV. LED's tend to have pretty jagged spectrums and can put out a lot of UV. Fluorescents are even worse in those regards. But printing papers and filters were designed with incandescent bulbs in mind, so they're as close to perfect as you'll find.

Like I said before, if you really want to get serious with LED bulbs, I would consider the Hue or Lifx lights as probably the way to go. They have the option to display over 16 million colors and over 1,000 shades of white. They use a combination of red, green, blue, and white LED's in their bulbs, so they shouldn't have any major dips in their spectrum that can't be tuned out. So it should be possible to find an appropriate color that will work with any setup, color or variable contrast B&W. They are also dimmable. The problems are that they are software controlled and pretty expensive, plus the Hue bulbs require a hub. I've never attempted to use one, so I have no idea how practical they are in use, nor how difficult it would be to tune it to work appropriately.
 

Doremus Scudder

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Where are you guys getting all that graded paper? I only know of Foma anymore, and that only in a couple of pretty-contrasty grades... VC has taken over just about everything.

However, as long as one can get a usable range of contrasts from VC paper with an LED light source, things should be manageable. Due to the variation in spectral output of different bulbs, one would have to do specific testing. I doubt if contrast "grades" on VC paper are exact even with different incandescent sources, since age, line voltage, etc. can all change the color temperature of the bulb. I've got five or six ELC bulbs for my Chromega heads and all of them are slightly different in output and color temperature.

Doremus
 

Sirius Glass

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Uh, let me think. The one that fits into my enlarger.


Did I get that right?
 

Nokton48

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Modern Enlarging Systems Model 2 on DII 1 by Nokton48, on Flickr

LED Printing Baby Yeah!
Modern Enlarging Systems Model 2 LED Enlarging Head on my venerable 4x5 DII

Modern Enlarging Systems Model 2 on DII 2 by Nokton48, on Flickr

LED Printing Baby Yeah!
Modern Enlarging Systems Model 2 LED Enlarging Head on my venerable 4x5 DII


According to a thread I found after seeing this unit on Ebay, making these was a labor of love for Emil. He is no longer producing these units. AFAIK they fit only Omega D and E enlargers (which is good with me).


Peruse here: http://www.modernenlargerlamps.com/Modern_Enlarger_Lamps/Welcome.html

This is an uber awesome LED head. Yes the Model 2 works with Multigrade filters. The Model 3 allows VC printing by controlling the print head contrast with an Iphone 4S.
 
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Arklatexian

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ic-racer said:
How even is the illumination? I presume there are no words or letters on the plastic diffuser. If you have some multigrade filters you should test it and see.
Click to expand...
The letters on the GE bulbs that I bought are on the side, just like a tungsten enlarger bulb. I don't notice any "delay" when they are turned on and the illumination is very even. I also have an LED head for my 4x5 D11 and will compare the light from the GE bulbs with that and, of course the first test will be using the multigrade filters. I only do B&W. Just think. No Heat. That makes it worth trying if nothing else.........Regards!
 

Nokton48

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I have a freezer full of Kodak Ektalure "R" salon paper 8x10 to 16x20. When I run out of graded paper I will investigate VC printing with this head.

Round LED bulbs are all over our house. 99 cents each at IKEA
 
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