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Darin Boville
16-Dec-2013, 00:06
I'm struggling with track lighting. I want to buy about 40-50 linear feet of track and two dozen track heads using LED bulbs for a gallery0style environment. Want to keep it on the inexpensive side.

But I'm bewildered by all the different bulb types.

In LED, what's my best move as far as bulb type? (That will determine my fixture type, too, of course.)

What degree of spread would be right for a gallery environment, lights about 10-12 feet up, installed at any angle I desire (i.e. tracks not installed yet).

Thoughts on color temperature of the bulbs?

--Darin

gleaf
16-Dec-2013, 00:20
Issue with LED bulbs is heat sink ventilation. I will do some research in the morning. Many need clear airspace around them.

Amedeus
16-Dec-2013, 00:40
There are many factors playing here. LED lighting is getting better all the time.

I've settled on PAR38 spot lighting, warm for lighting up individual prints/frames up to 16x20 ... for my larger pieces I'm using PAR38 flood, soft white warm. My throw is few feet shorter than yours.

No issues with cooling.

YMMV.

polyglot
16-Dec-2013, 18:09
If you're keen on LED, you need to worry about colour quality (the uniformity of the spectrum, i.e. how close it is to blackbody with no big spikes or holes in the spectrum) as well as colour temp. Make sure the CRI of the bulbs is over 90 otherwise things can look wrong.

Classic tungsten gallery lighting is 3600K and that will work well if the gallery as a whole is lit at those sorts of temps. You could also use about 5200K (sunlight) but that requires that you don't use tungsten lighting elsewhere, or the prints will look like they're in blue highlights.

In selecting bulbs, I would buy a couple of individual fixtures and test out a handful of different bulb brands with a few different print technologies (B&W, RA4, inkjet and maybe ilfochrome if you can get it). Different print technologies have different ink spectral responses, so while one kind of print might look OK under a bulb with poor CRI, a different kind of print might look quite inaccurate due to different dye selections.

Amedeus
16-Dec-2013, 19:36
I second polyglot on the CRI ... higher is better and preferably over 90 since that is where the reputable, more expensive brands are. Some of these LED lamps put out less light compare to the lower CRI lamps ... so look for the compromise.

Darin Boville
16-Dec-2013, 20:55
I second polyglot on the CRI ... higher is better and preferably over 90 since that is where the reputable, more expensive brands are. Some of these LED lamps put out less light compare to the lower CRI lamps ... so look for the compromise.

And brand recommendations (or better, links?). I know the quality of lighting is important but I'm also very conscious of price.

--Darin

Darin Boville
16-Dec-2013, 20:56
Make sure the CRI of the bulbs is over 90 otherwise things can look wrong.

Can I trust the CRI of the no-name brands? The big names are sooo much more expensive...

--Darin

Amedeus
16-Dec-2013, 22:47
No, you can not in my experience ... I do lighting development for a living and can measure all parameters around light bulbs. There's a difference and you pay for it.

No different than buying fluorescent tubes ... KinoFlo over residential tubes ... way different in performance ...

YMMV ... what is not good enough for one, is perfect for the other.



Can I trust the CRI of the no-name brands? The big names are sooo much more expensive...

--Darin

Darin Boville
16-Dec-2013, 23:35
No, you can not in my experience ... I do lighting development for a living and can measure all parameters around light bulbs. There's a difference and you pay for it.

No different than buying fluorescent tubes ... KinoFlo over residential tubes ... way different in performance ...

YMMV ... what is not good enough for one, is perfect for the other.

What brands should I look at that are not quite good enough for a pro like you but probably not absolute junk? :) I see a big difference in LED prices....

--Darin

Nathan Potter
17-Dec-2013, 11:01
The differences in LED lighting prices result from the CRI values and the efficiency of the heat sinking. The CRI value derives from the particular mix of RGB emitters that are used. To best match a true black body radiator requires a lot of work optimizing the mix of RGB diodes at the factory. The best now can achieve a CRI of 100 (a near perfect match). From what I've seen a CRI of 90 is adequate for the faithful viewing of color prints and is nearly irrelevant for black and white prints. But ultimately the CRI one uses depends on how fussy you are.

Heat sinking costs money and bulk around the bulb but is essential for long life.

I've always thought there should be a disclaimer in galleries about the lighting, stating what the gallery lighting is and that prints, especially color, will look much different in home lighting if the spectral output at the home is materially different than that in the gallery.

There is a wealth of stuff on the web about CRI values and heat sinking. The best advice is to pick up some likely candidates and try them out, particularly to evaluate the angle of spread. The historic intensity at the print for critical viewing is at least 100 FC but some galleries can and do vary this for print preservation purposes.

Nate Potter, Austin TX.

Amedeus
17-Dec-2013, 12:38
I'm not aware of any residential RGB LED lights ... all the ones available on the market to consumers are blue LED driving a phosphor converter much like what's happening in fluorescent tubes. It is the careful blend of phosphors and the compromise between light output and CRI that yields CRI in the 90 arena.

Nathan's RGB approach is absolutely valid but is in use in specialty lighting at significant premiums. In some of our medical lighting we use 4-6 wavelengths to get closer to the natural black body curve. There is more to CCT and CRI than just the numbers ... how close you adhere to the black body curve determines how colors match the natural sun light spectrum at that given color temperature.

There are a few entertainment and photography wash lights out there equipped with RGB LED clusters but expect to pay $250+ for those.

The need for heatsinking is well understood in the LED lighting design world but heatsinks and properly binned LED's are expensive etc ... hence the slight premium you pay for these. Not saying the $12 LED bulbs from C*** don't work, they do but the color rendition is just not there. Expect to pay $30-$40 for PAR38 style spot or flood lights that you'll be reasonable happy with when it comes to lighting up art work.

I just did an exhibit covering a 12" wide display, 6" high with 4 Philips A19 floods, warm white at 2700K, 830 lumens/bulb (11 Watt) and the visitors of my display commented how much more natural and pleasant the colors looked compared to other displays where cool white or CFL's where used. Google the spec and you'll find that this lamp can be had below $20 online. Hardly a barrier to pick one up and try this out to see if this works for the coverage you need at the throw distance you'll be working with.

I choose this solutions as I had to run the display for 6 hours of a battery/inverter solution. Had adequate light at good quality.

YMMV.


The differences in LED lighting prices result from the CRI values and the efficiency of the heat sinking. The CRI value derives from the particular mix of RGB emitters that are used. To best match a true black body radiator requires a lot of work optimizing the mix of RGB diodes at the factory. The best now can achieve a CRI of 100 (a near perfect match). From what I've seen a CRI of 90 is adequate for the faithful viewing of color prints and is nearly irrelevant for black and white prints. But ultimately the CRI one uses depends on how fussy you are.

Heat sinking costs money and bulk around the bulb but is essential for long life.

I've always thought there should be a disclaimer in galleries about the lighting, stating what the gallery lighting is and that prints, especially color, will look much different in home lighting if the spectral output at the home is materially different than that in the gallery.

There is a wealth of stuff on the web about CRI values and heat sinking. The best advice is to pick up some likely candidates and try them out, particularly to evaluate the angle of spread. The historic intensity at the print for critical viewing is at least 100 FC but some galleries can and do vary this for print preservation purposes.

Nate Potter, Austin TX.

Drew Wiley
17-Dec-2013, 12:55
LED and CFL might be getting incrementally better, but it's still relatively abominable in terms of display color and eyestrain. I am not amused. And now they will pass screw-in halogens in lieu of ordinary tungsten household bulbs, but have banned production of the traditional alternative, so there will certainly be many many more houses burning down due to the extreme heat of those things where they don't really belong. Amazes me that no one thought of the long-term health implications to all this when the so-called energy-efficiency lighting rules were enacted. Nor do many of these new bulbs last very long at all, but that's probably due to the fact that most of them are dirt cheap import junk, just like so many other things nowadays. I keep testing the damn things, but it's still going to be awhile before they equal any kind of traditional display lighting. CFL's were code for new construction in certain cities around here well before the national law; and it's ironic that I was indeed able to get a moderately good representation of color of an installation of multiple large prints I did in one of those building, while I cannot myself even enter the building to view them or I'll get a migraine headache from the wacky spectrum.

Drew Wiley
17-Dec-2013, 13:48
Amedeus - there is one low-cost RGB LED system out there, but given both the specific mfg (Phillips) and the specific distribution channel, I'd be extremely skeptical of either the quality or the long-term viability. Display lighting of photography can be tricky, esp if you are selling prints for display under conditions different from your own lab standard. I keep a light bank of several sources on hand, just like a good lighting store with its multiple booths, to evaluate these inevitable predicaments. And things like color dyes and even black and white toners can do strange things under some of these new light sources which hypothetically shouldn't happen if one believed the marketing hype. That's symptomatic of any discontinuous spectrum. The alternative - low-voltage halogen - equals a lot of UV and heat, so is not an ideal solution either.

Darin Boville
17-Dec-2013, 14:48
One solution to the problem of having different lighting at the gallery vs the buyers home--after all, the lighting will *always* be different--is just to let the buyer bring it back if it doesn't suit. No risk, no worries, most people would never know the difference anyway.

As for bulbs, is this the one you mean, Amedeus? http://www.amazon.com/Philips-424382-11-watt-Household-Dimmable/dp/B00B4CPL5W

Not sure if that is the best price--I just posted the link to the first one I found...

--Darin

chris_4622
17-Dec-2013, 16:18
You can look into http://borealislighting.com/

I use their products for a few different applications. Don't be fooled by the lack of an external metal heat sink, they have a different way of dealing with that.

Drew Wiley
17-Dec-2013, 16:21
Bring it back???? Many prints are one of a kind, or otherwise unrealistic to reproduce, might have been printed to a specific color standard to begin with, and might
realistically cost up to a thousand dollars just to frame. And Phillips home lighting general equates to junk - you don't get something for nothing. Decent alternative
lighting isn't the kind of thing you're likely to encounter on Amazon or at Home Cheapo. Takes a bit more homework than that.

Darin Boville
17-Dec-2013, 16:32
Bring it back???? Many prints are one of a kind, or otherwise unrealistic to reproduce, might have been printed to a specific color standard to begin with, and might
realistically cost up to a thousand dollars just to frame. And Phillips home lighting general equates to junk - you don't get something for nothing. Decent alternative
lighting isn't the kind of thing you're likely to encounter on Amazon or at Home Cheapo. Takes a bit more homework than that.

Yes, bring it back. Like high end stereo speakers, just bring them back.

Printing to a certain color and lighting standard? Well, I would hope so! Of course it won't match what is in the buyer's home but you have to have a baseline.

As for frames, I am not, nor will I ever be, in the frame business. :)

And I'm doing the homework now! This thread is part of it....

--Darin

Randy Moe
17-Dec-2013, 16:54
I know you are looking for track lighting, but I use these wherever I can, great for Chicago winter. Menards sells them in a 2 pack also. I love the light they produce.

8000K Sky White turns dark into actual daylight.

http://www.menards.com/main/lighting-ceiling-fans/light-bulbs/fluorescent/sylvania-32-watt-t8-fluorescent-bulb-30-pack/p-1735911-c-6337.htm

Drew Wiley
17-Dec-2013, 16:58
Me too, Darin.... Mostly I'll let other people be the guinea pig first. I need to relamp somewhere down the line in the next few months, and I do dabble with personal testing, but am also relying on feedback from others, at least until true spectrograms get published etc. I have a good friend who specializes in high-end lighting,but these are true professional architectural installations, not just simple bulb replacements. But from time to time I ask his opinion. And my own eyes are especially
sensitive to off lighting. I genuinely get terrible headaches and even frizzy vision from some of these wierd things. Nature just didn't design us for discontinuous
light sources.

Darin Boville
17-Dec-2013, 17:07
Wow--I don't think I've seen 8000k bulbs before. Probably not what I want in this specific situation but intriguing nonetheless.

--Darin

Drew Wiley
17-Dec-2013, 17:28
8000K bulbs are designed for jewelry shops, specifically to make white diamond sparkle more brilliantly. Literally. The bulbs I hate are the meat counter fluorescents
which contain an ingredient which makes small amounts of hemoglobin itself fluoresce red. The steak look juicy red and fresh in the store, but then when you actually
take it from the wrapper, it's relative gray-green and conspicuously old. Not much different than displaying typical baryta black and white prints under halogens,
where the UV makes the optical brighteners really pop.

polyglot
17-Dec-2013, 18:26
8000K is very blue. It's what you get in shadows lit by blue sky light instead of sunlight and is the sort of lighting you'd use an 81B filter under!

I wouldn't use it to illuminate a print.

Randy Moe
17-Dec-2013, 19:13
I have no windows, so 8000K light is welcomed. I made my last wife a painting studio with 24, 6500K high CRI T12's 25 years ago, in a 12x18 eggshell white studio. She considered it better than painting outside. I became fond of light.

I think I used something like these, the detached studio looked like a spaceship had landed in the snow. Obviously, it had windows. I was trying to duplicate the paint color lighting at paint stores.

http://www.grainger.com/product/GE-LIGHTING-Fluorescent-Lamp-3DXP2?functionCode=P2IDP2PCP

Amedeus
17-Dec-2013, 20:08
Drew,

I've been testing general LED lighting solutions since 2008 and specialty LED (RGB white) lighting solutions since 1997. In general, you get what you pay for. It takes 12 LED wavelengths to come close to a Xenon arc lamp @ 5600K and about 8 wavelengths to come close to a tungsten incandescent burner at 3200K with CRI >98. It is possible, but it cost money. Some of my applications involve medical where pathology is determined by minute differences in color. Even there the incandescent and Xenon arc sources are disappearing in favor of multi wavelength LED.

I won't talk about CFL ... that boat never floated when it came to quality of light, even with tri-stimulus phosphors.

The problem indeed is that our body responds to black body lighting curves as that is genetically and evolutionary programmed in at color temperatures between roughly 20,000K and 1,800K ... any spectrum that significantly deviates will affect us in one or other way.

The local DIY stores have blue and warm yellow LED lighting. Folks born in Asia predominantly grasp for the blue white while Westerners (US and Europe) predominantly choose for warm white at 2700-3000K ... mostly based on what one grew up with it. I know there are exceptions but there's a good amount of sales statistics supporting this.

YMMV ... as usual ...

Cheers,


LED and CFL might be getting incrementally better, but it's still relatively abominable in terms of display color and eyestrain. I am not amused. And now they will pass screw-in halogens in lieu of ordinary tungsten household bulbs, but have banned production of the traditional alternative, so there will certainly be many many more houses burning down due to the extreme heat of those things where they don't really belong. Amazes me that no one thought of the long-term health implications to all this when the so-called energy-efficiency lighting rules were enacted. Nor do many of these new bulbs last very long at all, but that's probably due to the fact that most of them are dirt cheap import junk, just like so many other things nowadays. I keep testing the damn things, but it's still going to be awhile before they equal any kind of traditional display lighting. CFL's were code for new construction in certain cities around here well before the national law; and it's ironic that I was indeed able to get a moderately good representation of color of an installation of multiple large prints I did in one of those building, while I cannot myself even enter the building to view them or I'll get a migraine headache from the wacky spectrum.

Amedeus
17-Dec-2013, 20:19
Drew,

Can you be specific about the low cost RGB LED system ? Is it the A***e wash-light ?

Totally agree with Drew that lighting of art in general is not a sinecure and is difficult to do on a budget ... but there are reasonable sources that are affordable. (Anything over 10 foot throw I use PAR38 spot lighting and that get's more expensive, still not perfect light but neither is incandescent light a perfect light ... )

Most if not all inks are developed under black body curve lighting and the "new" lights don't have necessarily the same spectrum, so the result is metamerism ... colors are not displayed as they should be because the wavelengths to bring them out are simply not there. Add to this that cheap CFL and some poorly designed LED white phosphor converters leak UV (CFL) and deep blue (LED) ... these interact in a undesirable way with the white brighteners. Not good either way.

YMMV.


Amedeus - there is one low-cost RGB LED system out there, but given both the specific mfg (Phillips) and the specific distribution channel, I'd be extremely skeptical of either the quality or the long-term viability. Display lighting of photography can be tricky, esp if you are selling prints for display under conditions different from your own lab standard. I keep a light bank of several sources on hand, just like a good lighting store with its multiple booths, to evaluate these inevitable predicaments. And things like color dyes and even black and white toners can do strange things under some of these new light sources which hypothetically shouldn't happen if one believed the marketing hype. That's symptomatic of any discontinuous spectrum. The alternative - low-voltage halogen - equals a lot of UV and heat, so is not an ideal solution either.

gleaf
18-Dec-2013, 06:22
Vaughn or another North Coast Ca member may be able to tell you what Swanland uses in the gallery upstairs. It is track lights and has dimmer controls. One short stop over didn't help me on the details. Too busy looking a the Ansel Adams prints. Or just call them Swanland's Camera (707) 442-4522 good friendly folks.

Drew Wiley
18-Dec-2013, 09:34
Process control lighting is obviously a different thing than display lighting. In the lab I have very precise high-CRI lightboxes as well as viewing lights at 5000K as well as 4200K, but supplement these with optional viewing bulbs which simulate more typical home or gallery conditions. Then I had a mockup gallery set up in my studio for an extrapolated sense of display, esp with bigger prints, but this particular area is an utter mess at the moment awaiting rewiring and remodeling. CFL's do indeed seem to be especially prone to metamerism, even with basic Spottone-style spotting dyes. I just wish I have bought up a serious lot of good tungsten display bulbs in advance, but you can only stretch your budget so many ways at once, and in the long run, any commercial gallery in this area would be code-mandated to have a different kind of lighting anyway. There are obviously good options color-wise with low-voltage halogens, but these crank out a lot of heat and UV -certainly not the best thing for color prints. So it's largely a wait-and-see game with me in terms of where LED lighting evolves from here. CFL's could
hypothetically be properly balanced just like high-CRI fluorescent tubes, but the market forces right now definitely put the priority on the mass-distribution of
the junk side of this category - and I do mean junk. Things will improve over time. We can all contribute to the experimentation side of things.

Nathan Potter
18-Dec-2013, 11:07
Amadeus, thanks for pointing out that most of the low cost LED lamps actually use mixed energy gap phosphors to convert the LED blue (and UV?) energy to the visible range. I can see the cost advantage of doing such and should have figured that out. Phosphor output is at discrete wavelengths so I can imagine that with enough overlapping narrow bands one could, in principle, very closely approximate a black body profile. But I suppose to keep mfg. costs low a small number of phosphors are used so these consumer LEDs' have a rather spiky output. Is there a place on the web that shows the spectral response in the visible range of many of the common bulbs?

Nate Potter, Austin TX.

Drew Wiley
18-Dec-2013, 11:43
It's largely guesswork without a true published spectrogram, which is something one should expect with legit architectural pro lighting options. By contrast, consumer
oriented lighting is just misleading market-oriented BS, as usual. And so far, I haven't personally seen any actual published LED sources without certain significant spiky anomalies or gaps.

Nathan Potter
18-Dec-2013, 15:10
Yes Drew, as I look at a few published spectrographs I see they are really spiky with seldom more than three emission peaks that are not very sharp and poorly overlapped. I think these are indicative of poor purity of phosphors - no doubt for cost reasons. The little I've fooled around with the consumer level LEDs' using my Ilfochromes the more disappointed I am compared to the simple halogen spots at 3400 K, I believe.

For the fun of it and for home viewing purposes I want to somehow try using my I1pro spectrophotometer to evaluate and compare incident light color response on the Ilfochromes for LED vs halogen illuminators. Haven't quite figured out if this would be possible in a reflective mode - I need to think out a workflow that provides accurate results.

I don't actively sell prints but have on occasion to small company lobbies where they become decorative art with a theme. Some of these folks are switching to LED lighting for my prints and I think they look awful in some cases. Perhaps it's more about what you are used to - possibly there is some visual adaptation going on. Dunno.

Nate Potter, Austin TX.

Darin Boville
18-Dec-2013, 16:00
Back to practical questions... :)

Which bulb do I get? Cost is a big factor. Once I know what bulb (and thus which base) I can explore inexpensive light heads.

Earlier in this thread Amedeus suggested a bulb that *sounded* like this bulb: http://www.amazon.com/Philips-424382-11-watt-Household-Dimmable/dp/B00B4CPL5W but that was never confirmed. Is this a good (good enough) one? Other suggestions?

--Darin

Richard Wasserman
18-Dec-2013, 16:04
Are Solux 3500K lamps still about the best that are easily available in terms of print viewing accuracy, not necessarily energy efficiency?

Drew Wiley
18-Dec-2013, 16:39
I don't know if people like Solux still have inventory. You'd have to contact them. But part of the problem here is that you don't get something for nothing. There's
is a distinct bifurcation between architectural lighting products and "affordable" consumer things distributed through the usual suspects. For example, I can get a four pack of low-voltage halogen bulbs like I use in one of my enlargers for about two bucks (wholesale), made in China, and they'd probably blow up in about two days. So I only use Japanese Ushio bulbs, which cost about sixteen dollars apiece. Same goes for companies like GE. Most of their consumer lighting products are absolute junk, and you won't even find any true technical info on file about them. But their professional lighting has all kinds of tools, including published spectrograms. Unfortunately, I no longer have a working continuous-tone spectrophotometer to do my own testing. But I think LED options are still in their infancy, and will slowly improve.

Nathan Potter
18-Dec-2013, 20:34
The bulb I recommend is a Solux. Type depends on the distance from bulb to print surface. 10 feet is a very long throw. I'd use a Solux PAR 38, 3500 K, 90 watt, #06858 throwing a 10 degree beam yielding an approximately a 2 ft, beam diameter at 10 feet and an illuminance of about 75 FC. These are 120 volts. The 3500 K bulb really is fine with some of my Ilfochrome prints, seeming to pull more shadow detail. I think they will be about $15 per bulb with a 2500 hour life and they are tungsten filamented. Google various suppliers. Eico makes a quality product. Of course they can be dimmed for quiet times.

As Drew says Ushio is a top rated producer of lamps but my only experience is with their mercury bulbs used for lithography for I line sensitive resists. Their 250 to 2000 watt mercury bulbs top all others in performance - stability of output and longevity.

Nate Potter, Austin TX.

Amedeus
18-Dec-2013, 23:50
CFL's could
hypothetically be properly balanced just like high-CRI fluorescent tubes, but the market forces right now definitely put the priority on the mass-distribution of
the junk side of this category - and I do mean junk. Things will improve over time. We can all contribute to the experimentation side of things.

Well put Drew

Amedeus
18-Dec-2013, 23:58
Amadeus, thanks for pointing out that most of the low cost LED lamps actually use mixed energy gap phosphors to convert the LED blue (and UV?) energy to the visible range. I can see the cost advantage of doing such and should have figured that out. Phosphor output is at discrete wavelengths so I can imagine that with enough overlapping narrow bands one could, in principle, very closely approximate a black body profile. But I suppose to keep mfg. costs low a small number of phosphors are used so these consumer LEDs' have a rather spiky output. Is there a place on the web that shows the spectral response in the visible range of many of the common bulbs?

Nate Potter, Austin TX.

You are correct that the phosphors are the limiting factor since most white LED general lighting bulbs are driven by blue LED. (Few specialty white LED's are driven by UV and converted by tri-stimulus phosphors ... expensive)

The first generations had blue LED light and a yellow phosphor ... lack red and have the typical blue hue ... cool white, daylight etc. The current crop of soft white LED bulbs have a broader band phosphor that emits a bit more in the red and passes less blue through ... voila ... 2700K CCT and a CRI that better than the initial 60-70 ...

CRI of 90 is where it becomes acceptable for most ... I didn't say "ideal" or I would suggest tungsten halogen technology with IR/UV coating and these things are expensive, use a lot of power and require special fixtures.

We'll get there with LED as the gallery and museum world is pushing for energy efficient lighting with a CRI of at least 95 and a reasonable approximation of the black body curve whatever the CCT is.

As I stated before, for our medical lighting we use 4-6 wavelengths and are working on 7 where two of them are driving phosphors ... not cheap but we get CRI of 97 with great red rendition.

Amedeus
19-Dec-2013, 00:00
That's the compromise LED bulb Darin I've been using on my latest exhibit ... confirmed ... inexpensive enough to see if you like it. Standard socket, so if you don't like it, any other halogen tungsten spot/PAR will fit.


Back to practical questions... :)

Which bulb do I get? Cost is a big factor. Once I know what bulb (and thus which base) I can explore inexpensive light heads.

Earlier in this thread Amedeus suggested a bulb that *sounded* like this bulb: http://www.amazon.com/Philips-424382-11-watt-Household-Dimmable/dp/B00B4CPL5W but that was never confirmed. Is this a good (good enough) one? Other suggestions?

--Darin

Amedeus
19-Dec-2013, 00:20
Agreed, the current available consumer LED lighting shows typically two spikes. The warm color lamps have a increased output in the 600-650nm range. You can google and quite a number of good images/links show up. Sorry, can't post my data because of internal IP rules.


It's largely guesswork without a true published spectrogram, which is something one should expect with legit architectural pro lighting options. By contrast, consumer
oriented lighting is just misleading market-oriented BS, as usual. And so far, I haven't personally seen any actual published LED sources without certain significant spiky anomalies or gaps.

Darin Boville
19-Dec-2013, 01:13
That's the compromise LED bulb Darin I've been using on my latest exhibit ... confirmed ... inexpensive enough to see if you like it. Standard socket, so if you don't like it, any other halogen tungsten spot/PAR will fit.

Bingo, thanks. I'll look for a source to buy by the dozen.

Whew, reading through this thread makes me realize that computer world color management is trivial compared to real world color management!

--Darin

jp
19-Dec-2013, 08:57
Appreciate the link for the bulb. I'll get one sometime and try it alongside the mix at home.

I've got a mix of incandescent, CFL, and LED bulbs at home because I'm inordinately interested in electrical stuff and making good digital photos with existing light. I've got some $10-ish 3000k LED lights from Lowes which are good, but not as good as incandescents. Good enough that I insulated right over the access hatch in the attic for changing the bulb over our stairway. I have not found any CFLs I really like. I use them for cheap lighting in the garage, or places like a floodlight I didn't want to go 15' up on a ladder to change. Color is nasty with CFL.

gleaf
19-Dec-2013, 10:25
You may find that a single standard source for the gallery space is not appropriate and may need to build a light box to test response of the proposed displays to the available light sources.

Jim Andrada
19-Dec-2013, 15:17
I been using the Solux PAR lamps - but I think they stopped making them around the end of last year so I doubt there'd be any left. I should probably give them a call and ask what they recommend these days.

Drew Wiley
19-Dec-2013, 16:30
Quite a few ordinary types of tungsten bulbs become illegal even to ship after Jan 1st, and were stopped from production awhile back. Seem like the national priority
is to save household energy by having houses self-heated by burning down, since hot hazardous halogens are ironically now an allowed substitute. Combined with
junky made-in-China floor lamps, it becomes easy.

Drew Wiley
26-Dec-2013, 16:49
The best sources for high CRI LED display lighting seem to be Sylvania/Osram, Cree, and Toshiba. In my case, about the best basic track lighting bulb I can find at 4000K has a CRI around 85 - not bad, but going above that, all the common lamp types seem much too warm (3000K). And that's in the thirty to fifty dollar per bulb range. Osram has a very good information sheet on LED design, efficiency, and technical options for achieving high CRI, along with examples and spectrograms. It's just a matter of time before I purchase some and see for myself. But I've got to repaint my display walls first anyway. And it does seem that LED technology is going
to answer our needs much faster than CFL design, which is temperamental anyway.

Nathan Potter
26-Dec-2013, 17:24
Drew, I've had very good luck with Osram bulbs for industrial applications especially microscope lamps and a range of lamps for instrumental analysis equipment. Lifetime is usually better than advertised. I suspect this may follow for their LED line of bulbs but have not used any yet. They would be my choice for a supplier.

Nate Potter, Austin TX.

DennisD
26-Dec-2013, 19:12
FYI this is from the trenches without extensive testing and analysis with precise equipment.

For my business we've been experimenting and beginning to use a LED product called Kolourone made in Korea. Http://kolourone.com/about.php

The illumination of our product is color critical, but like many other businesses we're cautious about our budget. We will be needing about 350 bulbs. Specifically we've been using the Kolourone 2700K and 3500K par38 style bulbs suitable for track fixtures. Price is around $35+/- per bulb off the shelf.

So far, we find the color temperature of both types mentioned to be accurate and very acceptable to the eye as well as in direct comparison (side by side) with incandescents. The consistency of color from bulb to bulb is excellent. We've used the 3500k bulbs for showroom window lighting and find they give the needed bright punch from a long viewing distance.

The 3500K bulbs should be excellent for gallery style lighting.

We use the 2700K's for interior showroom lighting where a warmer light is important and desirable.

The CRI of the product is mid 80's, if memory serves me, 84 to be exact.

I would defer to the lighting experts who have commented earlier, but wanted to relate our hands on experience.

gleaf
26-Dec-2013, 20:22
Konica Minolta has some serious color measurement test equipment available. You might want to contact them and find out when then next one day show and tell technical course is in your area. We were testing the color of computer displays. Most of the attendees here were either auto industry interior materials and paint engineers or medical prosthetic folks working on visible facial prosthetics. Color gets complicated quickly.

ramon
2-Jan-2014, 09:14
The best sources for high CRI LED display lighting seem to be Sylvania/Osram, Cree, and Toshiba. In my case, about the best basic track lighting bulb I can find at 4000K has a CRI around 85 ...

I best source I have found is a LED with 95 CRI @ 5000K (GSPW1653JTE-50Z from japanese Stanley-Electric). Its also sold in a PCB board in UK/EU by rs-components (ILH-SJ01-WW95-SC201).

The led is very expensive but buying a complete reel (1000 units, if I remember right) has a big discount.

I though of 5000K and 95 CRI as a perfect light table source and also a perfect source for DSLR scanning.

I was also in contact with some local taiwanese PCB manufacturers and manufacturers of lighting products (Aluminium PCB substrate), to make some kind of 4x5" LED light source with this LED. Don't know if this idea looks interesting. If so, I wonder if we can organize together some kind of group buy.

Drew Wiley
2-Jan-2014, 09:38
Under the category of actually available track lighting bulbs, there are less options than the hypothetically available choices. So there's still a difference between basic display lighting in basic existing fixtures and serious architectural lighting, or what might be done for experimentally. Trying to make an accurate colorhead using LED lighting would still involve some tricky hurdles compared to halogen. The "full spectrum" effect in architechtural lighting is obtained by mixture of the LED's, whereas in an ideal additive colorhead you'd need to have relatively pure separate R,G,and B sources. There would be no significant advantage to LED's in subtractive
printing. But it's inevitable that someone will want to try. Making a black and white head to replace a cold light source would be much easier. But the basic topic here
is track lighting.

Darin Boville
8-Jan-2014, 02:04
Reporting back in. The Phillips bulb mentioned earlier didn't work out so well--too dim and non-directional. On the the other hand I'l be replacing the regular bulbs in my house with this one as I run out of the old ones.

What I did find is a $17 BAR30 at Costco that looks very promising. I *think* this is the bulb--the one I have is installed and hard to get to:

http://www.feit.com/led-lamps/performance/dimmable/reflector/par30-s-ledg5

The CRI is low--its says ">80", whatever that means. Visually it appears very slightly cooler than the CFLs I have in my office but cleaner looking, too. Haven't bought more than a single unit yet, still looking for something better in that price range. One advantage of Costco is that I can take the damn things back if they don't last very long...

I need to find a cheap head, new or used. This stuff really adds up!

--Darin

Darin Boville
8-Jan-2014, 02:31
Well, this is interesting. I've been looking around for one of those rebate deals where Costco or Home Depot sell LED lights with a $10 subsidy for the local utility--nothing. Then I see this: http://www.designingwithleds.com/crees-new-tw-series-led-bulb-qualifies-for-ca-utility-rebates-with-a-93-cri/

It says that starting on January 1st of this year a LED bulb must have a CRI of at least 90 to quality for a subsidy and a good red rating, to boot. Hopefully something will go on rebate very soon...

--Darin

ramon
8-Jan-2014, 03:01
Thanks Darin. Interesting option with high CRI, but just only 2700K.

jp
8-Jan-2014, 06:43
I put the Phillips bulb in one of my kitchen's ceiling cans. I also have another LED bulb and incandescents and have in the past used a CFL or two. The Phillips bulb was visually indistinguishable from the incandescents. It's not terribly directional, which is great for my use. The real test would be some portraits with the DSLR. They seem to render skin and hair poorly with CFL and some LED bulbs. I'll get to trying that with the Phillips.

Drew Wiley
8-Jan-2014, 09:36
Darin, at this point in history you'll probably discover you need to pay about twice as much per bulb to get serious quality - which might actually be cheaper in the
long run anyway, since cheapo consumer bulbs from big box outlets are contracted to be cheapo, and don't seem to last very long - rarely what they claim.

Darin Boville
8-Jan-2014, 14:18
Darin, at this point in history you'll probably discover you need to pay about twice as much per bulb to get serious quality - which might actually be cheaper in the
long run anyway, since cheapo consumer bulbs from big box outlets are contracted to be cheapo, and don't seem to last very long - rarely what they claim.

I know, I know :) My problem is for the project I'm working on--opening a photo space (still a secret, sssshhhh)--I want to keep the budget down as much as possible. And those $7 bulbs after rebate--if I can ever find a rebate!--will save hundreds of dollars and still give me light that 99.9% of the people will not notice a problem with--and the other 0.1% will understand my situation. I hope.

If anyone knows of any rebates going on elsewhere in the country I'd love to hear about them...

--Darin

PS The brand Costco sells is sort of iffy, as you say. I bough that same brand of CFL and they don't last while the Phillips and GE CFLs that I have in the same fixture just keep going. It's a short term/long term problem. If I spend more to get better bulbs in the short term I may run out of money for the project before the long term!

fluconnrotary1
10-Jan-2014, 03:48
Idea of using LED in gallery is very nice

Darin Boville
1-Mar-2014, 14:11
(I'm double posting this--it from a different thread here on LFF--just to keep the lighting thread up-to-date with information on the changing CRI requirements, at least in California. The question I'm answering is asking me for more info on my lighting....).

It's just the cheapest Lowes track light head I could find ($10 each) coupled with the cheapest LED PAR30 LED I could find, at Costco ($18). I'll be adding ten more heads later this week for a total of thirty. That includes a 4-head track I haven't installed yet to light up the alcove on the left. Six of those lights are broad beamed lights, the rest are narrow beam.

Now, here's the one bummer. These bulbs often goon rebate at Costco--$5 off, $8 off. It really adds up. I waited for a rebate but no luck. Why no rebate? Because California's new rules, in an effort to increase the *quality* of the bulbs, now require, as of January 1, that any bulbs on rebate must be at least 90 CRI. My bulbs are in the mid to high 80s. So I'm at Costco yesterday and I see the broad beam bulbs but different packaging. The new, high CRIs, have arrived. I bought three to try out. No narrow beams yet. No doubt a rebate will soon be offered.

--Darin

gleaf
2-Mar-2014, 06:07
Thank you for the update. Back of my mental worry corner is how clean is the emitted light spectrum. Visible to please you your eye can do. Damaging UV not so. For florescent the unadvertised and unlabeled (undocumented feature) and very present UV end is very hard on color materials, destroys plastic lamp shades etc. Take care there is no image eating UV.

Darin Boville
2-Mar-2014, 12:00
Thank you for the update. Back of my mental worry corner is how clean is the emitted light spectrum. Visible to please you your eye can do. Damaging UV not so. For florescent the unadvertised and unlabeled (undocumented feature) and very present UV end is very hard on color materials, destroys plastic lamp shades etc. Take care there is no image eating UV.

Frankly, I have no idea whether LEDs emit any worrisome levels of UV. Anyone?

If so, how would I check?

--Darin

Randy Moe
2-Mar-2014, 13:11
There are spectra emission graphs. I don't think it's a problem, but I am not 100%. Where's Drew when we need him?


Frankly, I have no idea whether LEDs emit any worrisome levels of UV. Anyone?

If so, how would I check?

--Darin

Peter De Smidt
2-Mar-2014, 14:56
Normal ones for home lighting should be ok. There are special UV LED bulbs, but those are used for lighting reef aquariums and similar. Isn't standard museum lighting 3500K Solux?

John Olsen
2-Mar-2014, 15:12
We're in the process of converting from incandescent track lighting to LEDs in the same fixtures. We asked for 2700 degree LEDs because that would match to the existing, allowing a gradual transition. Unfortunately, the first batch sent was the wrong temperature, 2400. The attached shows the ugly color mismatch. Lesson: don't waste your time on wrong color temperature bulbs. I am looking forward to the eventual LED transition however, because we're running up to the manufacturer's current limit now.
111476
111477

Merg Ross
2-Mar-2014, 22:29
Where's Drew when we need him?

Not sure, perhaps he made a quick trip to New York to check out galleries. My guess is that he will be back in the Bay Area on Monday. Have to wait and see.

Amedeus
2-Mar-2014, 23:17
White LED lamps are driven by blue LED's and phosphor converted ... there is no UV to worry about ... one of the major advantages of LED phosphor converted white light. There's also little to non IR in the output as the IR is pulled out from the back in contrast to tungsten lighting which has always Ia significant amount of IR in the output and a minimal amount of UV.


Frankly, I have no idea whether LEDs emit any worrisome levels of UV. Anyone?

If so, how would I check?

--Darin

gleaf
3-Mar-2014, 06:06
Drat darn heck darn spit. Apologies for my Paranoia generated by earl CFL's. Reached up to undo the plastic ceiling light cover to remove the dead bug layer and had it crumble in my hands. I wouldn't buy a $300 meter for one use. How about calling UC Santa Cruz and talking to the physics department or the environmental side? Apologies one more time. I retired and have not completely adjusted to not having the tech toy storage shelves at hand.

BetterSense
3-Mar-2014, 08:16
Possibly relevant:


http://www.oscars.org/science-technology/council/projects/ssl/index.html

Drew Wiley
3-Mar-2014, 09:11
Don't expect CFL's to amount to anything. It's an interim technology plagued by junk mfg. LED is already leapfrogging past them. I'm going to soon test some Bulbrite
PAR's in 4000K, 85 CRI. There are other options. But these will screw right in and claim to have a long burn life. Most CFL's fail miserably quickly and are subject to
all the startup fluctuations of cheapie tube fluorescents.

ROL
3-Mar-2014, 10:20
We're in the process of converting from incandescent track lighting to LEDs in the same fixtures. We asked for 2700 degree LEDs because that would match to the existing, allowing a gradual transition. Unfortunately, the first batch sent was the wrong temperature, 2400. The attached shows the ugly color mismatch. Lesson: don't waste your time on wrong color temperature bulbs. I am looking forward to the eventual LED transition however, because we're running up to the manufacturer's current limit now.
111476
111477

Dumb questions: Which pic is which? What does that mean "manufacturer's current limit now" - limit of what?

ROL
3-Mar-2014, 10:31
Most CFL's fail miserably quickly and are subject to
all the startup fluctuations of cheapie tube fluorescents.

Not to mention the UV a 75w CFL equivalent puts out in a reading lamp requires reapplication of an 80 SPF sunscreen three times a day ;).

We've changed out all exterior lighting to LED (cans, candelabra types) and solar and can now leave them on all night, though we'd never do that. Beautiful. I just can't wait until LEDs totally supplant CFLs economically, and functionally and the only reason we'd be using incandescents is to keep nests or freezing plants warm. Pretty much the only thing left worth living for.

Darin Boville
30-Apr-2014, 13:06
A follow up. Back in post #51 I mentioned that California had a new law that said that if anyone wanted to offer a rebate on LED lights starting January 2014 then those lights had to meet a higher color quality standard than before.

When I was buying my lights for the gallery the CRI of the bulbs was <90 and they were about $18 each--there weren't any rebates in January/February because, I figured, they were still trying to get rid of old stock that didn't meed the new law.

So I'm at Costco today and I see the new bulbs are out--and on rebate. I bought a dozen for my office/printing area to replace the CFLs that were there before.

haven't done any serious A/B comparisons but my impression is that the light seems "cleaner."

Light bulbs are:

BR30 Flood by Feit Electronic
LED Dimmable (broad beam)
750 Lumens (claimed energy cost of $1.57/year, based on 3 hours/day at 11 cents kWh)
13 Watts
CRI 93+
2700K
$9.99 each

The room DOES look good now, but maybe it's my imagination...

--Darin

John Olsen
1-May-2014, 12:18
Dumb questions: Which pic is which? What does that mean "manufacturer's current limit now" - limit of what?

Sorry ROL. The top one is so ugly that I failed to be more explicit. I'm still waiting for some 2700 degree LEDs to replace these 2400s.

And by "current limit" I meant the amount of electrical current the tracks are warranted to carry. When we do switch to LEDs in the future, we will have a much better safety margin. We're taking this transition slowly as switching 84 lights represents a big investment.

Drew Wiley
2-May-2014, 08:18
High-quality LED's that will fit in ordinary voltage track fixtures are still in the approx forty buck range per bulb, esp in the selection I'm interested in (4000K, approaching 90CRI, but not quite there). Warm bulbs way down there in the 2000's K give a poor rendition of blues etc. But probably better than the CFL's out there,
which are no doubt an interim technology anyway, as LED lighting steadily improves. So I'm just tinkering and experimenting now, because LED prices will slowly drift
down and the color quality go up.

algarzai
28-Jul-2014, 19:33
i am renovating my gallery and installing a new lighting system. i am thinking 3500-5000k would be excellent. on a budget of course. but i want something good because almost everything i have bought cheap i have regretted in the end.

i have spent the last hour reading this thread. so which bulbs?! lol

Peter De Smidt
28-Jul-2014, 21:06
Solux. http://www.solux.net/cgi-bin/tlistore/infopages/index.html

Darin Boville
29-Jul-2014, 01:03
i am renovating my gallery and installing a new lighting system. i am thinking 3500-5000k would be excellent. on a budget of course. but i want something good because almost everything i have bought cheap i have regretted in the end.

i have spent the last hour reading this thread. so which bulbs?! lol

I'd still go with the Costco bulbs, on rebate. The new ones have a better CRI than the ones I bought and for about ten dollars a bulb....try a few before spending $$$$ on a high-end system that the customer won't be able to replicate at home anyway.

--Darin

Drew Wiley
29-Jul-2014, 13:48
The problem with excellent bulbs like Solux is that ugly low-e products are being mandated by code. Now to get a legal bulb you have to either put up with something toxic like mercury or severe eyestrain, or a fire hazard. That's what I call progress!

Peter De Smidt
29-Jul-2014, 15:01
Not around here, at least not yet! If color is important for the images, then I really don't know of a better option than Solux. Even the 90 cri alternatives can lead to dramatic color shifts. For bw, that might be ok.... I use Solux at home for my picture lights. They're not that expensive, and you don't have to use their fixtures.

Ashly85
22-Aug-2014, 02:47
Classic tungsten gallery lighting is 3600K and that will work well if the gallery as a whole is lit at those sorts of temps. You could also use about 5200K (sunlight) but that requires that you don't use tungsten lighting elsewhere, or the prints will look like they're in blue highlights.