Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: wayne_eddy on July 19, 2015, 09:00:09 am
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Hi all,
I have been after a new light source for my study/digital processing room for some time now thought I would first consult LL for advise.
My current set up is a Dell U27 (27") monitor and a secondary Samsung 24". I only calibrate the Dell and the second monitor is mostly for Photoshop windows, palettes, layers etc. The Dell is calibrated with a Spyder 4 Elite.
Though I do have a pretty
Current lighting;
Minimal ambient lighting at night when I do most of my processing, during the day there is little light coming in through a couple of windows a meter behind the monitors (the windows have good blinds).
At night I operate a halogen desk lamp placed behind the main Dell monitor and it disperses it's warm light across the wall and blinded windows behind that monitor.
Walls in the room are pretty much white.
I estimate the strength of the halogen bulb to be 50-50W.
So ideally, I wouldn't mind an LED light source with a flexible stem I can point about if needed that stands about 30-40cm tall.
I'm wondering if I should be looking for a specific light temperature for the new light - I feel I should be choosing something closest to daylight.
One last thing that may be important to some: I do not print at home.
What are you thoughts, opinions and experiences?
So I am after replacing
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http://www.soluxtli.com/cgi-bin/tlistore/infopages/index.html
https://www.solux.net/cgi-bin/tlistore/partaskdesk2.html
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if only their lamps weren't so mofo ugly and/or even 'in stock'.
Very disappointing and it's very hard to find a MR16 desk lamp these days. it's all LED or mini-halogen
And since the user is not printing at home (and maybe not even viewing the outside-done prints on them), is it
particularly 'important' that it be a Solux or D50-ish illuminant ?
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With all due respect, I think you are way over-obsessing about this light source. Some people get way kooky about this sort of thing, and that's because they are interested in the technology and not the photography. Go and take photos. Screw the light.
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if only their lamps weren't so mofo ugly and/or even 'in stock'.
Yes, the new lamp is ugly! I have two of the older black units which look better but the QC of the lamp is iffy. But the illuminant? Can't be beat outside of mother nature.
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Go and take photos. Screw the light.
First point is a good one. 2nd, not so much. At least viewing printed output next to your display, it's rather important.
Screw the light, your prints are in the dark, don't look very good. ;)
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Interesting thread. Raises a question. If you don't have this special lamp, what and when are is best for viewing your print?
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First point is a good one. 2nd, not so much. At least viewing printed output next to your display, it's rather important.
Screw the light, your prints are in the dark, don't look very good. ;)
It is my understanding that you do not want to view prints next to the display (as in literally "next to"). This is why I have set up my studio so that I have a print display area (corkboard with Solux lamps) off to the left of my workstation. Thus, it is physically impossible for me to see a print and a screen image at the same time. I do not recall where this advice came from, probably these forums, but it has worked for me.I look at the screen, then I must pivot my head to look at the print. Back and forth, back and forth. The result is that I am very pleased with how my prints match my soft-proofed images.
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It is my understanding that you do not want to view prints next to the display (as in literally "next to").
Well next to needs to be defined. ;D How would you decide you've produced the desired WYSIWYG between display and print if you didn't view them next to each other? Run from computer room to the other room where the print is being illuminated? That's not going to work.
You want the viewing both ideally about 90 degrees from the display and such that NO light spills on the surface of the display, that affects you perception of black.
This is why I have set up my studio so that I have a print display area (corkboard with Solux lamps) off to the left of my workstation. Thus, it is physically impossible for me to see a print and a screen image at the same time.
But you can move your field of view quickly and ensure that the two match or don't. What you describe is the 'correct' procedure, one just has to control light spill, control the other ambient light.
(http://digitaldog.net/files/Print_to_Screen_Matching.jpg)
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Interesting topic.
I found this making a search. This is from an Australian point of view ...
http://www.colourstandards.com.au/monitor_display.html
¿?
As I have a white ceiling in my room I do illuminate with a few 50W lamps the ceiling in order to get an even ilumination more or less
Checking again looks like there is a new ISO 12646:2015
http://www.iso.org/iso/home/store/catalogue_ics/catalogue_detail_ics.htm?csnumber=57311
One more ;)
https://www.google.com.mx/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&cad=rja&uact=8&ved=0CFQQFjAHahUKEwjP8_Hs7OfGAhUNQZIKHUr-BQk&url=http%3A%2F%2Fwww.colorlab.no%2Fcontent%2Fdownload%2F28878%2F330518%2Ffile%2FSole2010.pdf&ei=6--rVY_SA42CyQTK_JdI&usg=AFQjCNEjCE7NHPIeYQSO_GHHeEQd8srd3w&sig2=J2YoggmojNcfehMoYMJY3A
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The SoraaVivid PAR30L/product number 00807 is the best full spectrum 5000K Daylight LED for home use I've found on the market. It puts out over 1000 lumens. It's still puts out heat but not as much as a halogen.
Here's a discussion on paper OBA's and various lights that includes the Soraa and Solux examples at the bottom of this thread...
http://photo.net/photography-lighting-equipment-techniques-forum/00dNjR
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https://www.solux.net/cgi-bin/tlistore/partaskdesk2.html (https://www.solux.net/cgi-bin/tlistore/partaskdesk2.html)
This uses their 120v screw-in PAR20 3500K bulb. Is this what you meant to recommend?
If you want to DIY with the Solux 12v 4700K bulbs, you can get fixtures for 12V MR-16 halogen bulbs at hardware stores. I got a fixture (designed for outdoor lawn lighting) at Lowe's. I got a 60 watt 12v transformer at Home Depot (both are in the US.) The electrical supply sections have boxes, wires, switches, etc. I mounted the fixture to an old mike stand (but a light stand would work.)
Some people use MR-16 track lighting mounted to some stand.
Wayne
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This uses their 120v screw-in PAR20 3500K bulb. Is this what you meant to recommend?
If you want to DIY with the Solux 12v 4700K bulbs, you can get fixtures for 12V MR-16 halogen bulbs at hardware stores. I got a fixture (designed for outdoor lawn lighting) at Lowe's. I got a 60 watt 12v transformer at Home Depot (both are in the US.) The electrical supply sections have boxes, wires, switches, etc. I mounted the fixture to an old mike stand (but a light stand would work.)
Some people use MR-16 track lighting mounted to some stand.
Wayne
Can you take a picture of your setup and post it here. That sounds rather complicated for the OP's purposes since all he wants is to provide ambient light for editing on his monitor, not for print matching.
Though I am interested in the parts you found at Home Depot & Lowes since I have the Solux MR16 4700K but the Tailored Lighting Eiko task lamp power plug crapped out after 40 hours of use.
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Hi,
I would say that most exposures are limited by flare. I have seen this from analysing a lot of images in RawDigger. Very few images reach down in the shadows.
Essentially, any image containing a significant amount of bright sky would be limited in DR by flare. On the other hand, dark church interiors with small bright windows may have a full dynamic range.
Best regards
Erik
Can you take a picture of your setup and post it here. That sounds rather complicated for the OP's purposes since all he wants is to provide ambient light for editing on his monitor, not for print matching.
Though I am interested in the parts you found at Home Depot & Lowes since I have the Solux MR16 4700K but the Eiko lamp power plug crapped out after 40 hours of use.
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Can you take a picture of your setup and post it here?
Not handily. I have a very small studio/computer room and I'd have to move a lot of stuff that is clustered around that fixture. But I can link to the salient parts:
First, the exact fixture I used is discontinued, but this one is very similar:
Portfolio Black Low Voltage 50-Watt (60W Equivalent) Halogen Spot Light (http://www.lowes.com/ProductDisplay?partNumber=357112-30383-LV11318BK&langId=-1&storeId=10151&productId=3567098&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1)
(Lowes)
Lightech 60-Watt 12-Volt Electronic Transformer (http://www.homedepot.com/p/GE-Lightech-60-Watt-12-Volt-Electronic-Transformer-GELT60A12012DIY/203586278) (Home Depot)
They also have a 150 watt transformer if you want more headroom.
Lightech 150-Watt 12-Volt Electronic Transformer (http://www.homedepot.com/p/GE-Lightech-150-Watt-12-Volt-Electronic-Transformer-GELT150A12012DIY/203586269)
I got a box large enough to hold the transformer + connecting wire, a heavy duty 120v cord, and wire nuts from the electrical supply section. I wired everything together and taped the fixture to the top of a mike stand. I plugged it into an outlet strip that has a circuit breaker.
I am intrigued with the Soraa lamp you mentioned. I just looked and the only place I can find it in the US is at
https://www.1000bulbs.com/product/114368/LED-00807.html (https://www.1000bulbs.com/product/114368/LED-00807.html)
But they show it as being back ordered until the end of August. Do you have a link to any place that might have them in stock?
Wayne
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This uses their 120v screw-in PAR20 3500K bulb. Is this what you meant to recommend?
Sure, why not? The values of the bulbs don't necessarily match what comes out, at least the one's I've measured. The higher CCT that one might suspect are preferable due to the value themselves don't necessarily produce the most pleasing color rendition, the CCT 3500K bulbs look great. I find the CCT 4700K bulbs can appear 'too cool' depending on the task.
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Hi,
I would say that most exposures are limited by flare. I have seen this from analysing a lot of images in RawDigger. Very few images reach down in the shadows.
Essentially, any image containing a significant amount of bright sky would be limited in DR by flare. On the other hand, dark church interiors with small bright windows may have a full dynamic range.
Best regards
Erik
Erik, are you referring to this thread... http://forum.luminous-landscape.com/index.php?topic=102203.0
We're talking about desk lamp lights, not dynamic range limited by flare.
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Not handily. I have a very small studio/computer room and I'd have to move a lot of stuff that is clustered around that fixture. But I can link to the salient parts:
First, the exact fixture I used is discontinued, but this one is very similar:
Portfolio Black Low Voltage 50-Watt (60W Equivalent) Halogen Spot Light (http://www.lowes.com/ProductDisplay?partNumber=357112-30383-LV11318BK&langId=-1&storeId=10151&productId=3567098&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1)
(Lowes)
Lightech 60-Watt 12-Volt Electronic Transformer (http://www.homedepot.com/p/GE-Lightech-60-Watt-12-Volt-Electronic-Transformer-GELT60A12012DIY/203586278) (Home Depot)
They also have a 150 watt transformer if you want more headroom.
Lightech 150-Watt 12-Volt Electronic Transformer (http://www.homedepot.com/p/GE-Lightech-150-Watt-12-Volt-Electronic-Transformer-GELT150A12012DIY/203586269)
I got a box large enough to hold the transformer + connecting wire, a heavy duty 120v cord, and wire nuts from the electrical supply section. I wired everything together and taped the fixture to the top of a mike stand. I plugged it into an outlet strip that has a circuit breaker.
I am intrigued with the Soraa lamp you mentioned. I just looked and the only place I can find it in the US is at
https://www.1000bulbs.com/product/114368/LED-00807.html (https://www.1000bulbs.com/product/114368/LED-00807.html)
But they show it as being back ordered until the end of August. Do you have a link to any place that might have them in stock?
Wayne
Wayne, thanks for the links to the individual electrical components for building an MR16 lamp fixture. Like I said that's way too complex of a DIY project I'ld want to get into. Though I am mechanically inclined as was tested by the military back when I was a senior in high school I was way too afraid of 120 voltage electronics. Install a 12 volt sound system with amps, crossover network and subs in my car? No problem. Your setup scares the crap out of me.
I just checked my Amazon order history where I bought the Soraa from 1000bulbs and you're right, it's not currently available. Don't know what to tell ya'. Maybe buying direct from the manufacturer or going to their site will direct you to other retail suppliers.
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Though I am mechanically inclined as was tested by the military back when I was a senior in high school I was way too afraid of 120 voltage electronics.
Yeah, you shouldn't do something that you aren't comfortable with. I used to experiment with electronics several decades ago. Which included making power supplies from scratch so I was used to wiring line voltage stuff.
I forget that most technical people aren't near as likely to be into hardware electronics anymore. Which is probably why Radio Shack just gave up the ghost.
Wayne
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Yeah, you shouldn't do something that you aren't comfortable with. I used to experiment with electronics several decades ago. Which included making power supplies from scratch so I was used to wiring line voltage stuff.
I forget that most technical people aren't near as likely to be into hardware electronics anymore. Which is probably why Radio Shack just gave up the ghost.
Wayne
My local Radio Shack here in New Braunfels, TX is actually hiring.
Found a place online selling the Soraa 00807 indicating it should ship by July 31, 2015...
http://www.elightbulbs.com/catalog_product.cfm?source=AmazonCSE&prod=SC00807&pageurl=http%3A%2F%2Fwww.amazon.com%2Fgp%2Foffer-listing%2FB00P97UKCM%2Fref%3Dolp_tab_new%3Fie%3DUTF8%26condition%3Dnew&sku=SC00807
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Sure, why not? The values of the bulbs don't necessarily match what comes out, at least the one's I've measured. The higher CCT that one might suspect are preferable due to the value themselves don't necessarily produce the most pleasing color rendition, the CCT 3500K bulbs look great. I find the CCT 4700K bulbs can appear 'too cool' depending on the task.
The Kelvin of the lamp is going to effect the light balance and colors depending on which lamp you use. 6500K is natural, 5000K is natural white, 3500K is warm. Shouldn't you pick a lamp and its Kelvin rating based on the type of light you intend to show the prints under?
http://www.planetbulb.com/pages/What-is-Kelvin-Color-Temperature%3F.html
Handy chart of Kelvin for artificial lights and outdoor sunlight at differing times. http://www.wpsphoto.org/KelvinTemperatureChart.pdf
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The Kelvin of the lamp is going to effect the light balance and colors depending on which lamp you use. 6500K is natural, 5000K is natural white, 3500K is warm. Shouldn't you pick a lamp and its Kelvin rating based on the type of light you intend to show the prints under?
I don't know where you got that idea about 'natural' anything and further it's important to keep in mind that any CCT Kelvin value is a large range of possible colors!
http://www.ppmag.com/reviews/200512_rodneycm.pdf
Showing your prints could occur under any number of different possible illuminants that are not anywhere near the illuminate of your viewing booth sitting next to the display. Do you think one has to (one can) match exactly the illuminant for the print and whatever is backlighting the display? Unlikely. And yet we can produce a close visual match between the two with some trial and error in how we calibrate the display white point.
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Found a place online selling the Soraa 00807 indicating it should ship by July 31, 2015...
http://www.elightbulbs.com/catalog_product.cfm?source=AmazonCSE&prod=SC00807&pageurl=http%3A%2F%2Fwww.amazon.com%2Fgp%2Foffer-listing%2FB00P97UKCM%2Fref%3Dolp_tab_new%3Fie%3DUTF8%26condition%3Dnew&sku=SC00807 (http://www.elightbulbs.com/catalog_product.cfm?source=AmazonCSE&prod=SC00807&pageurl=http%3A%2F%2Fwww.amazon.com%2Fgp%2Foffer-listing%2FB00P97UKCM%2Fref%3Dolp_tab_new%3Fie%3DUTF8%26condition%3Dnew&sku=SC00807)
Thanks. Ordered.
I've been studying some color science textbooks and it looks to me that there are lies, damned lies and color rendering indices. The CRI metric is dicey at best. (Page 216 of Wyszecki and Stiles's Color Science, 2nd edition shows the spectral graphs of two extremely spikey and bogus looking illuminants that are CRI 100.) And CRI is all there is (officially).
"In the eye of the beholder" is the best we can do. I want to try those Soraa bulbs and see if they work any better for copy stand work than my "high CRI" CFLs.
Wayne
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The CRI metric is dicey at best.
It's kind of a joke. It was primarily designed by Fluorescent light manufacturers to make their products look much better to unsuspecting consumers than they really are. There are BCRA tiles used to compare under a reference light source but only eight. That's too small a set of tiles. That make it easy to create a spectrum that will render the 8-14 tiles and doesn't tell us that the light source is full spectrum. It doesn't tell us how the other colors will render. My understanding is there are two reference sources; Tungsten for warm bulbs and D50 for cool ones: Above and below 4000K. That means that a normal tungsten bulb and perfect daylight both have a CRI of 100! As such, a high CRI is a decent gauge of how well a light will preform in your home but not such a great indicator of how well it will work for photography and proofing. Both a Solux bulb and a "full spectrum" tube from home depot may have a CRI of 97. I can assure you the Home Depot bulb has a giant mercury spike and some spectral dead spots.
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Andrew: the reason I asked the question about Kelvin, was because I was thinking about my 25 year-old lightbox that I believe was set at 5000K so that slides would display at the closest to what is actually in the film. Now is realize we're talking now about prints and reflected light, but wouldn't the light's Kelvin effect the colors you see in the print.
In other words, if you are comparing a print with the monitor's colors and white balance, wouldn't these be different depending on which Kelvin you selected? Just like 5000K was the usual standard I believe for lightboxes, is there a recommended Kelvin for a viewing booth light?
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As such, a high CRI is a decent gauge of how well a light will preform in your home but not such a great indicator of how well it will work for photography and proofing.
Yes. CRI (such as it is) is based on the eye's tristimulus response. The tristimulus response of cameras is only an approximation of the human eye's tristimulus.
Both a Solux bulb and a "full spectrum" tube from home depot may have a CRI of 97. I can assure you the Home Depot bulb has a giant mercury spike and some spectral dead spots.
As I posted in another thread (http://forum.luminous-landscape.com/index.php?topic=100698.msg827493#msg827493) I got a ColorMunki Display + ArgyllPro ColorMeter (http://argyllcms.com/pro/) to measure SPDs. The first thing I measured was my Home Depot CRI 93 CFLs. Yep, they are spikey. (All the 5500K CFLs I measure had a CRI > 90, no matter whether they are marketed as being "full spectrum" or not. The garden variety 5500K CFLs from Home Depot (etc.) all have approx. the same spectrums and measurements of CRI > 90 as the Home Depot "Full Spectrum" CFLs do.)
However, I also measured the Solux 3500K 120V screw in lamp I have and it's spectrum was a bit gnarly. It has a lumpy droop in the middle of it. (Attached--click to see the graph.) This was why I raised my eyebrows earlier in the thread when you recommended them. It is also CRI 86.
Wayne
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Andrew: the reason I asked the question about Kelvin, was because I was thinking about my 25 year-old lightbox that I believe was set at 5000K so that slides would display at the closest to what is actually in the film.
I'm not sure about this idea that because the Fluorescent lights in your lightbox is 'rated' as CCT 5000K, your slides display what's actually 'in the film'.
I also had such light boxes and tried to use the same make and model as my E6 lab so we were on visual parity. That's useful!
Now is realize we're talking now about prints and reflected light, but wouldn't the light's Kelvin effect the colors you see in the print.
AFAIK, print, display or slides on a box, it's all the same issue.
In other words, if you are comparing a print with the monitor's colors and white balance, wouldn't these be different depending on which Kelvin you selected?
The numbers are mostly meaningless because the don't tell us the exact color (unlike say D65 or any other standard illuminant), the numbers don't tell us anything about the spectrum, the numbers don't guarantee a visual match. It's only one part of the descriptor.
Analogy: I can tell you I've got a pixel who's value is R45/G8/B120. Does that describe the color? No. It's only a partial ingredient, we need the associated color space. Saying we have a CCT (that's important) 5000K anything is about as ambiguous as saying "I've got a pixel who's color is R45/G8/B120."
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However, I also measured the Solux 3500K 120V screw in lamp I have and it's spectrum was a bit gnarly. It has a lumpy droop in the middle of it.
Using an EyeOne Pro and various packages, I can replicate that.
(http://digitaldog.net/files/BableColor_LED_office.jpg)
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However, I also measured the Solux 3500K 120V screw in lamp I have and it's spectrum was a bit gnarly. It has a lumpy droop in the middle of it.
Using an EyeOne Pro and various packages, I can replicate that.
Your plot looks more like an older (CRI 66) 5000K LED than the 120V 3500K screw in Solux bulb. Are you sure that you posted the correct screen shot?
Wayne
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Your plot looks more like an older (CRI 66) 5000K LED than the 120V 3500K screw in Solux bulb. Are you sure that you posted the correct screen shot?
It's the now discontinued desk lamp from Solux (the black one).
The CRI numbers are not IMHO pertinent for reasons I've outlined already.
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Yes. CRI (such as it is) is based on the eye's tristimulus response. The tristimulus response of cameras is only an approximation of the human eye's tristimulus.
As I posted in another thread (http://forum.luminous-landscape.com/index.php?topic=100698.msg827493#msg827493) I got a ColorMunki Display + ArgyllPro ColorMeter (http://argyllcms.com/pro/) to measure SPDs. The first thing I measured was my Home Depot CRI 93 CFLs. Yep, they are spikey. (All the 5500K CFLs I measure had a CRI > 90, no matter whether they are marketed as being "full spectrum" or not. The garden variety 5500K CFLs from Home Depot (etc.) all have approx. the same spectrums and measurements of CRI > 90 as the Home Depot "Full Spectrum" CFLs do.)
However, I also measured the Solux 3500K 120V screw in lamp I have and it's spectrum was a bit gnarly. It has a lumpy droop in the middle of it. (Attached--click to see the graph.) This was why I raised my eyebrows earlier in the thread when you recommended them. It is also CRI 86.
Wayne
Did you or have you made a direct connection to how the spiky spectra of these artificial lights claiming high CRI affect perception of colors on a print viewed under these lights in preventing a match to a display that uses its own approximation visual system to counter the spiky LED/fluorescent backlight?
How can anyone claim accuracy according to a full spectrum standard D50/D65 lighting device by analyzing its spectra in order to get a match on another device that uses spiky or completely different lighting hardware?
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Did you or have you made a direct connection to how the spiky spectra of these artificial lights claiming high CRI affect perception of colors on a print viewed under these lights in preventing a match to a display that uses its own approximation visual system to counter the spiky LED/fluorescent backlight?
Not really. I haven't been doing Color Management as it is classically defined (matching a monitor to prints.) Since I got my ColorMunki I've been dabbling with Color Management techniques a bit, but I don't print for real at home. So I haven't tried to match prints with any real vigor.
How can anyone claim accuracy according to a full spectrum standard D50/D65 lighting device by analyzing its spectra in order to get a match on another device that uses spiky or completely different lighting hardware?
I don't think that a true D50 or D65 light source exists. And real daylight is spiky if you look at it closely enough. Page ten of Wyszecki and Stiles's Color Science has a plot of daylight measured at .25 nm that is very ragged.
You know that LED monitors are spiky. I'm attaching spectral plots of monitor white, red, green and blue. This is of a Samsung 2333HD monitor. The spikes in my NEC PA241W look very different.
I think that the consensus that I read in my color science textbooks is that measurements, no matter how precise, are no substitute for matching by eye. The human tristimulus mechanism isn't understood well enough yet to be replicated with instruments.
As Andrew has noted earlier in this thread, the CRI spec that is based on measuring eight (or fourteen) colors leaves a lot to be desired.
Wikipedia:
Ohno (2006) and others have criticized CRI for not always correlating well with subjective color rendering quality in practice, particularly for light sources with spiky emission spectra such as fluorescent lamps or white LEDs
https://en.wikipedia.org/wiki/Color_rendering_index#Criticism_and_resolution (https://en.wikipedia.org/wiki/Color_rendering_index#Criticism_and_resolution)
With this said, it would be helpful to have better color rendering metrics. They could at least try; instead of leaving us hanging with the existing CRI.
Wayne
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The CRI metric is dicey at best. (Page 216 of Wyszecki and Stiles's Color Science, 2nd edition shows the spectral graphs of two extremely spikey and bogus looking illuminants that are CRI 100.) And CRI is all there is (officially).
The current "fix" to the limitations of CRI is to make sure that the R9 value is greater than zero.
[ R9 is the CRI saturated red patch, which is not part of the average CRI Ra value. ]
The lighting industry appears to have successfully sabotaged several attempts to update CRI, although TLCI seems to have snuck around this by being a "Television Standard".
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How can anyone claim accuracy according to a full spectrum standard D50/D65 lighting device by analyzing its spectra in order to get a match on another device that uses spiky or completely different lighting hardware?
Standards like CRI attempt to do that in a practical manner by evaluating the delta E's that will result when viewing colors under each spectrum.
Where the current CRI falls down is in the limited range of colors it uses (R1-R8 are all pastels), and the way it averages the individual patch delta E's together, allowing a few good patches to swamp a really bad patch. Something like TLCI attempts to address these problems, as do the other proposed replacements for CRI.
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Seems to me the people we should be asking are those that have to match paint swatches to existing and/or older paint they sell to customers. There's nothing worse looking in interior design than to have subtle or pronounced paint mismatches on walls and a lot of that is compounded by mixed lighting in homes. Interior paint sellers must have to coddle a lot of picky customers and come up with excuses why their wall paint isn't matching.
That industry must have a better matching system than what's available to photographers or provided by existing color science matching and measuring methods.
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I offer this, as a relatively inexpensive 'daylight' solution:
http://www.bhphotovideo.com/c/product/728827-REG/Kino_Flo_488_K55_S_6P_4_Kino_800ma_KF55.html (http://www.bhphotovideo.com/c/product/728827-REG/Kino_Flo_488_K55_S_6P_4_Kino_800ma_KF55.html)
They work in any standard 4 foot flo fixture("shop lights" that you get a Home Despot, etc).
Yes, they are fluorescent, which means they have a discontinuous spectrum.
On the other hand, all LEDs have discontinuous spectrums, and tungsten-halogens with imperfect filters in front of them probably have fairly discontinuous spectrums as well.
Just a suggestion...
Oh, and KinoFlo is a well-established brand (for over 25 years) in the motion picture and televsion industry.
Ask any cinematographer if they 'make good stuff'.
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How is a $130 fluorescent tube considered relatively inexpensive?
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Typical Olino.org lamp test report that gives more than the CRI value and goes into the details of CRI values on another page.
http://www.olino.org/us/articles/2013/12/18/installerdirect-com-ge-led6-5d-gu10-840-fl-bx-dimmable
Lots of similar lamp test reports there. Dutch site with pages in English.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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How is a $130 fluorescent tube considered relatively inexpensive?
Well, actually, it's a 6pack of tubes.
You can also purchase individual replacement tubes from Just-Normlicht or GTI for approx $15-20 each
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Seems to me the people we should be asking are those that have to match paint swatches to existing and/or older paint they sell to customers. There's nothing worse looking in interior design than to have subtle or pronounced paint mismatches on walls and a lot of that is compounded by mixed lighting in homes. Interior paint sellers must have to coddle a lot of picky customers and come up with excuses why their wall paint isn't matching.
They don't have these problems because they do spectral matching. The match will be good under almost any lighting.
(And note that CRI is not about matching - it is about the appearance of the colors compared to what you would see if you were using a broad spectrum illuminant).
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Typical Olino.org lamp test report that gives more than the CRI value and goes into the details of CRI values on another page.
http://www.olino.org/us/articles/2013/12/18/installerdirect-com-ge-led6-5d-gu10-840-fl-bx-dimmable (http://www.olino.org/us/articles/2013/12/18/installerdirect-com-ge-led6-5d-gu10-840-fl-bx-dimmable)
They test a lot of parameters but most of them are of interest to light fixture installers. I think that the only parameters that are relevant to photographers are color temperature, CRI and chromaticity. With their definition of chromaticity being about how "white" the lamp is. See their Light with the color white (http://www.olino.org/us/articles/2010/03/06/light-with-the-color-white) explanation page. (Graeme, is Olino.org's chromaticity rating comparable to ColorMeter's Delta E metric?)
Olino.org's A close look at the Color Rendering Index (CRI, or Ra) (http://www.olino.org/us/articles/2009/11/30/a-close-look-at-the-color-rendering-index-cri-or-ra) page does a good job of driving a stake through the heart of CRI. Scroll down about 2/3 to Is the comparison index a good one? They show spectral graphs for three LEDish illuminants that have identical spectrum shapes, but differ in color temperature. The 3084 K one is CRI 94; the 3076 K one is CRI 83; and the 3019 K one is CRI 88.
A bit lower (CRI and led light bulbs) is a summary of tests commissioned by the CIE about how well the CRI works with white LEDs. Result: the CIE CRI is in general not applicable for a ranking on color rendition when white led sources are part of the observed illuminants. (I think that CRI is the only color rendering test that Olino.org has)
This is a great site, but unfortunately doesn't cover many (any?) lamps that are currently available in the US. We need someone in the US to set up a similar site. Preferably with more exacting color rendering tests. Maybe we shouldn't wait for official CIE color rendering tests.
Wayne
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The current "fix" to the limitations of CRI is to make sure that the R9 value is greater than zero.
[ R9 is the CRI saturated red patch, which is not part of the average CRI Ra value. ]
The CIE has apparently crept past CRI Ra:
As discussed in Schanda & Sándor (2005), CIE (1999) recommends the use of a ColorChecker chart owing to the obsolescence of the original samples, of which only metameric matches remain. In addition to the eight ColorChart samples, two skin tone samples are defined (TCS09* and TCS10*). Accordingly, the updated general CRI is averaged over ten samples, not eight as before.
https://en.wikipedia.org/wiki/Color_rendering_index#New_test_color_samples (https://en.wikipedia.org/wiki/Color_rendering_index#New_test_color_samples)
The lighting industry appears to have successfully sabotaged several attempts to update CRI, although TLCI seems to have snuck around this by being a "Television Standard".
Yes. I'm looking forward to TLCI (http://www.gtc.org.uk/tlci-results.aspx) tests. To test new technology LEDs, like the Soraa LEDs (http://www.soraa.com/) that Tim mentioned earlier.
Wayne
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Well, actually, it's a 6pack of tubes.
You can also purchase individual replacement tubes from Just-Normlicht or GTI for approx $15-20 each
I missed the (6 lamps) designation, Howard, but still I don't think the OP is going to need 6 four ft. tubes even as replacements since one tube can put out quite a bit of light and last for years. And there's the fixture that has to be installed. I did this for years with one 4ft. GE Chroma 50 I bought at Lowes installed high up on the wall behind my display. The light was just too bright and had a subtle magenta/light pink tinge that often made my calibrated display look greenish due to adaptation which is why I'ld discourage this setup.
Have it off to the side or behind the user but most of all out of direct line of sight with both display and light.
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And something of note I've noticed concerning artificial daylight/white light as ambient light around a display points to this nasty invisible or subtle hue on the green/magenta axis whose affects on adaptation is quite pronounced in fluorescent lights but LED's add a subtle cyan element that's close to the hue of cyan that makes up yellow/cyan mix of green. Within the pigment filtering mechanism some greens (more on the yellow side) aid in representing warmth (pale yellow/orange) in 4000K type daylight lights which is pretty much all of them. LED's tend to error on the cyan side of this warmth but it affects adaptation in unexpected and unpredictable ways.
In addition all custom incamera WB using a WhiBal card of fluorescent lights with my DSLR shooting Raw and developing in ACR always show an extreme over compensation of green by producing As Shot tint of +17 to +30 toward magenta. The Walmart Daylight LED's also do this.
However, the Soraa LED produces As Shot tint of -5 to -10 toward green. But my 6500K calibrated display neutrality when editing for long periods of time and going to the other room where I have the Soraa make its color of white look kind of greenish yellow.
Another reason to not have any artificial light in the line of sight of your display.
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They test a lot of parameters but most of them are of interest to light fixture installers. I think that the only parameters that are relevant to photographers are color temperature, CRI and chromaticity.
Wayne
The spectral plots at least add some information to the CRI numbers. The number of spikes etc. The radiation pattern is important for viewing lights too. Warming up time etc has been discussed here before. Given some illumination levels one wonders whether the scotopic / photopic spectral plots are insignificant for viewing lights. Aardenburg Imaging sets a minimum level of 500 Lux for critical color viewing and an optimal one at 2000 Lux.
Edit: Olino is switching to another color quality standard:
http://www.olino.org/us/articles/2015/03/07/color-quality-scale-cqs-measuring-the-color-quality-of-light-sources
As I understand it Olino will test a lamp when they receive it so there could be more US distributed lamps in the range. I do not expect a US initiative for similar independent tests soon.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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We've got a person at work who likes this:
http://fiilex.com/products/V70.php
I'm by no means an expert, but would be interested in thoughts.
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i wondered about the fiilex v70 lamp also. the "dense matrix led". that must be why they are able to offer different color temps. which is interesting and could be quite effective for comparing colors of objects (besides just prints) under different lighting colors.
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Edit: Olino is switching to another color quality standard:
http://www.olino.org/us/articles/2015/03/07/color-quality-scale-cqs-measuring-the-color-quality-of-light-sources (http://www.olino.org/us/articles/2015/03/07/color-quality-scale-cqs-measuring-the-color-quality-of-light-sources)
This is good to hear. Robin Myers Imaging's SpectraShop (http://www.rmimaging.com/spectrashop.html) also supports CQS.
I got the Soraa LED that Tim mentioned earlier in this thread. I tested it. First, here is a bog standard 5000K Philips LED that I got at Home Depot for less than $10 (USD):
(http://pics.fishcreekstudio.com/Other/Spectrum-10/i-djX9PHw/0/M/0001_Screenshot_2015-08-07-21-38-17-M.jpg)
Here is the Soraa 00807
(http://pics.fishcreekstudio.com/Other/Spectrum-10/i-cVgxHLJ/0/M/0002_Screenshot_2015-08-07-15-04-48-M.jpg)
(I'm using a ColorMunki that is UV cut. I think that the Soraa LEDs emit higher in the UV range, but a ColorMunki can't see UV.)
And here is an MR-16 50 watt Solux 4700K lamp
(http://pics.fishcreekstudio.com/Other/Spectrum-10/i-6MdNScJ/0/M/0003_Screenshot_2015-08-07-15-06-06-M.jpg)
Every 5000K LED that I've gotten from local hardware stores has measured very similar to the Philips. The Soraa LED is something different. I'm not too thrilled about the dip in the blues and that ColorMeter is only rating it at CRI 89.6 (I tried several measurements, from various angles and they all were about the same. It is possible that the ColorMunki's UV cut affects the CRI measurement for the Soraa lamp. Dunno.)
But it does look promising. It shows that LEDs can be improved. However, we still need better color rendering testing metrics. (Or for somebody to start testing human standard observers again.)
My eyes... after some quick tests, I think that the Solux lamp looks more like the light from the sun. But the Soraa is definitely better than any other LED (or CFL.) And is a whole lot easier to deal with than 12 volt MR-16 Solux bulbs are.
Wayne
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I'm getting a
Lavish Home Sunlight Desk Lamp, Black (26") thirty bucks 6500K 1300 lumens. I wonder if the lumens are the same lumens that tactical flashlight sellers use, i e followed by the square root of negative one.
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I'm getting a Lavish Home Sunlight Desk Lamp, Black (26") thirty bucks 6500K 1300 lumens
Would it be this one (http://www.amazon.com/Lavish-Home-Sunlight-Desk-Black/dp/B008E6BQXW)? If so, then it is a fluorescent lamp. The product info says that it is a "27-Watt bulb, with a C.R.I. (Color Rendering Index) of 80-85". For the record, here is a graph of the best (CRI 93) CFL bulb that I could find:
(http://pics.fishcreekstudio.com/Other/Spectrum-5/i-H6Z3Z58/0/M/Screenshot_2015-05-28-17-36-11-M.jpg)
Indoor Sunshine: Single 30-watt Spiral Bulb (http://www.amazon.com/Indoor-Sunshine-Single-30-watt-Spiral/dp/B001KYU5MS)
All the other fluorescent bulbs I tested were worse.
However...spectral plots don't tell the whole story. Even though the spectral plots for fluorescent lamps and LEDs look vastly different (see my previous post for the plot of a standard 5000K LED.), the light looks very similar to my eyes. My kitchen has a four bulb ceiling fan fixture. I put two of the above mentioned (my previous post) Philips 5000K LEDs and two ALZO 5000K LEDs (that test worse than the Indoor Sunshine LED) in the fixture at the same time. One side of the room was illuminated with the LEDs and the other with the CFLs. But the light looked identical.
As of right now, I think that the Soraa 00807 lamp that Tim recommended might be the best bet. But now 1000Bulbs is showing them as "Not for Sale. Reference Only (https://www.1000bulbs.com/product/114368/LED-00807.html)." eLightbulbs has them listed (http://www.elightbulbs.com/catalog_product.cfm?source=AmazonCSE&prod=SC00807&pageurl=http%3A%2F%2Fwww.amazon.com%2FSoraa-00807-SP30L-18-36D-950-03-PAR30LN-Flood%2Fdp%2FB00P97UKCM&sku=SC00807), but still out of stock. (I got mine from eLightbulbs so I can vouch for their service.)
This particular bulb is a bit large for a desk lamp. Soraa makes them in smaller form factors.
Wayne
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It is possible that the ColorMunki's UV cut affects the CRI measurement for the Soraa lamp. Dunno.)
My eyes... after some quick tests, I think that the Solux lamp looks more like the light from the sun.
I'd ignore the CRI numbers and pay far more attention to your eyes and the spectral plots. From what you've shown and described, you've saved me money NOT buying the Soraa! Thanks for that. Not ready for prime time despite the reports compared to Solux based on both your data points.
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However...spectral plots don't tell the whole story. Even though the spectral plots for fluorescent lamps and LEDs look vastly different (see my previous post for the plot of a standard 5000K LED.), the light looks very similar to my eyes.
The spikes indicate issues could arise with papers with OBAs. Or potential metameric failure.
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The spikes indicate issues could arise with papers with OBAs.
Tim was was concerned with OBAs when he mentioned the Soraa 00807 earlier in this thread (http://forum.luminous-landscape.com/index.php?topic=102190.msg838341#msg838341).
Soraa themselves say
"Unlike blue LEDs whose emission starts at 430nm, Soraa’s spectral emission begins at 400nm, providing all the fluorescent excitation needed to discriminate clearly between shades of white."
http://www.soraa.com/technology/VP3-natural-white (http://www.soraa.com/technology/VP3-natural-white)
The above linked Soraa page is titled "Simply Perfect Whites", and talks about how Soraa bulbs are better for evaluating whites. But am I correct that this intentional fluorescent excitation could cause issues with evaluating the effect of OBAs?
Wayne
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Thanks so much for posting the comparison info on the Soraa and other print viewing lights, Wayne.
Can you verify with your copy of the Soraa 00807 whether the front glass has micro cracks and if you get shadow halos testing by moving your hand closer and farther away between the light and a wall as demonstrated in the pics below?
Soraa claims they eliminated halos with their specially designed point source LED. When I emailed them through their website kiosk style email page they had one of their techs reply but now I can't find the email. It was odd looking simple text email with no headers or from/to and now it's disappeared and I can't remember what the tech wrote.
I just want to confirm with another non-biased customer who has the same model whether my copy has a manufacturing defect.
First Solux with their crappy Eiko task lamps power converter block going out with no help from Tailored Lighting and now Soraa with their shady style communications and lack of availability of their product online. Something doesn't smell right.
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Can you verify with your copy of the Soraa 00807 whether the front glass has micro cracks and if you get shadow halos testing by moving your hand closer and farther away between the light and a wall as demonstrated in the pics below?
I don't think that mine has micro cracks that look like yours. See attached image.
But I don't know about the shadow halos. The image I'm attaching doesn't show halos, but I don't know what distances you are using. How far is the light from the wall? What angles are involved? etc.
I did some ad hoc testing comparing against a CFL in another fixture and both had shadow halos at some distances/angles. And didn't at other distances/angles.
Something doesn't smell right.
I haven't read anything specifically about Soraa, but this article about Cree in (industry journal) LEDs Magazine indicates that the high end LED market is being squeezed:
Cree restructures LED business in face of mid-power onslaught
...Cree has announced restructuring in its LED manufacturing business that has been driven by higher than anticipated erosion on packaged LED selling prices...
http://www.ledsmagazine.com/articles/2015/06/cree-restructures-led-business-in-face-of-mid-power-onslaught.html (http://www.ledsmagazine.com/articles/2015/06/cree-restructures-led-business-in-face-of-mid-power-onslaught.html)
We want high end LEDs and are willing to pay a (reasonable) premium. But I think that the hordes of shoppers in WalMart (etc.) are a lot more interested in low price. IMO.
After writing the above paragraph, I looked up an article about Soraa where they are bragging about a color rendering test that they sponsored (they did well on the test.) But the magazine comments
The Penn St research, however, leaves more questions unanswered than it actually answers. There is the question of what premium people will pay for higher quality.
http://www.ledsmagazine.com/articles/2014/09/penn-state-research-on-color-rendering-reinforces-soraa-s-led-claims.html (http://www.ledsmagazine.com/articles/2014/09/penn-state-research-on-color-rendering-reinforces-soraa-s-led-claims.html)
The article goes on to note that there are now other companies marketing LEDs with improved color rendering. And veers into the knotty issue of color rendering tests.
I'm a bit concerned that Soraa stresses preferred colors, and not accurate colors. See the Soraa blog post (http://www.soraa.com/news/ctoblog-september-18-2014) about the rendering test that they sponsored. It sounds like Soraa lamps are designed to exaggerate chroma to a certain extent. (Maybe?)
But I am happy that at least the color rendering issue is being discussed.
Wayne
p.s., note that the blog I linked to has the email address of Soraa's Chief Scientist. He wants your comments...
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Thanks for those informative links, Wayne.
I found the Soraa emails in my "Sent" box but their subject line was "George Rasko...PAR30LAMP OPTICS", not Soraa. George Rasko is Soraa's applications engineer and he forwarded the pictures showing the shadow halos to the guy who designs the lenses for their lamps and this is what he said...
This is normal to me. Par30’s optical aperture is 84mm.
1st image: The distance between light source and the hand is only 8inch/200mm, under this condition I don’t think Soraa lamp is still considered as point source. Therefore, the edge will have multiple shadows.
2nd image: because the bike is very far away from light source. We can consider the lamp as point source. Therefore, the edge is very crisp.
That's why I never pursued this further. So the cracked glass has nothing to do with the shadow halos.
I've emailed Aurelien David, Soraa's Chief Scientist from the linked Soraa blog and I'll see what he says.
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So the cracked glass has nothing to do with the shadow halos.
But I am concerned about the cracked glass. Were the cracks always in your lamp? Or did the cracks develop over time?
One thing that spooked me when I was comparing my Soraa bulb with other bulbs this afternoon is that mine flickers for 10-20 seconds after power has been removed. I first thought that maybe the power switch to the fixture had gone bad and was arcing in the off position. But I unscrewed the Soraa lamp and it flickers even after being removed from the socket. I've never seen a bulb act like this.
Oh, if you want to take another look at Solux bulbs without having to do wiring, look at the Imatest Low cost DIY lighting (http://www.imatest.com/docs/lab/) setup. (You need to scroll down to Low cost DIY lighting.) It involves track lighting that that is bolted to a mike stand. But you don't need to do any wiring--There is a pre-assembled power plug that plugs into the track lighting fixture. I checked the links to the track lighting company and the links are still alive, so presumably you can still buy the track lighting.
Wayne
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But I am concerned about the cracked glass. Were the cracks always in your lamp? Or did the cracks develop over time?
One thing that spooked me when I was comparing my Soraa bulb with other bulbs this afternoon is that mine flickers for 10-20 seconds after power has been removed. I first thought that maybe the power switch to the fixture had gone bad and was arcing in the off position. But I unscrewed the Soraa lamp and it flickers even after being removed from the socket. I've never seen a bulb act like this.
I just noticed the cracks about a week ago after purchasing the bulb in March of this year which I didn't check at that time. Couldn't say if it was a gradual progression caused by the heat or it was that way when I bought it.
I don't have flicker issues with mine.
But all in all quite a few of the new daylight LED and CFL bulbs I've bought in the last 5 or so years that wasn't built by GE or Philips has had issues after extended use and some just sitting in a lamp but rarely turned on. My 4 year old Alzo is now vibrating with a loud buzz as of yesterday when I turned it on to compare to the Soraa. It didn't do this when I first bought it. The Walmart daylight LEDs are really doing well especially the two installed in an enclosed frosted decorative glass dome in my kitchen ceiling. I'ld thought they'ld crap out by now from the heat generated.
I think new startup bulb design makers employing new technologies may have a hard time finding, keeping or maintaining reliable manufacturing facilities and materials compared to the corporations that've been around longer with deeper pockets.
That Imatest MR16 track light setup looks like the way to go for even broad full spectrum lighting. Glad there's a way to plug the rig into a wall. Thanks for the heads up on that, Wayne.
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I think new startup bulb design makers employing new technologies may have a hard time finding, keeping or maintaining reliable manufacturing facilities and materials compared to the corporations that've been around longer with deeper pockets.
This stuff is tricky. I've been trying to improve my understanding of color science by reading books on color science. Color science books are generally treated as college textbooks and are priced accordingly (usually more then $100 (US)). However, I've been able to find earlier editions of these books a lot cheaper.
Principles of Color Technology, 2nd edition, by Billmeyer and Saltzman is still available for less than $6 (http://www.amazon.com/Principles-Color-Technology-Fred-Billmeyer/dp/047103052X). I highly recommend this book. It is one of the standard references for color science but is easy to read (it uses jokes and cartoons to illustrate points.)
I somehow managed to buy a used copy of Color Science: Concepts and Methods, Quantitive Data and Formulae, Second Edition by Wysecki and Stiles for less than $30 on Amazon, but I don't see it offered at anywhere this price now. Instead... (http://www.amazon.com/Color-Science-Concepts-Quantitative-Formulae/dp/0471399183)
The Wyszecki and Stiles book is tough reading anyway. It is very dense and is mostly dry technical proses with lots and lots of long equations. Needless to say, there are no jokes or cartoons. I read it, but I wouldn't want to take any test based on it.
I've been crawling the articles I linked to in my earlier post (http://forum.luminous-landscape.com/index.php?topic=102190.msg843308#msg843308) and (if you follow all the links in each article), a lot of color theory that is germane to the color rendering issues are covered fairly extensively. A lot of what is covered in the above two textbooks is covered in the articles (if you crawl all the links.) At least regarding color rendering.
FWIW, here is a copy/paste from my notes of links to the articles I crawled:
http://forum.luminous-landscape.com/index.php?topic=102190.msg843308#msg843308
http://www.ledsmagazine.com/articles/2015/06/cree-restructures-led-business-in-face-of-mid-power-onslaught.html
http://www.ledsmagazine.com/articles/2014/09/penn-state-research-on-color-rendering-reinforces-soraa-s-led-claims.html
Metrics aside, color rendering matters: http://www.soraa.com/news/ctoblog-september-18-2014
http://www.ledsmagazine.com/articles/2014/07/lumileds-delivers-broader-spectrum-in-crispwhite-cob-led.html
http://www.ledsmagazine.com/articles/2013/07/led-business-news-philips-financials-xicato-module-aixtron-epileds-crs.html
http://www.ledsmagazine.com/articles/2013/01/lighting-coalition-asks-epa-to-lower-energy-star-efficacy-specs-for-high-cri-lamps.html
MacAdams... http://www.ledsmagazine.com/articles/print/volume-9/issue-3/features/ssl-must-still-clear-hurdles-to-enable-mass-adoption-of-led-lighting-magazine.html
http://www.ledsmagazine.com/articles/print/volume-11/issue-4/features/technology/led-advancements-drive-quality-of-light-gains.html
http://www.ledsmagazine.com/articles/2012/05/understand-color-science-to-maximize-success-with-leds-magazine.html
http://www.ledsmagazine.com/articles/print/volume-9/issue-7/features/understand-color-science-to-maximize-success-with-leds-part-2-magazine.html
http://www.ledsmagazine.com/articles/print/volume-9/issue-10/features/understand-color-science-to-maximize-success-with-leds-part-3.html
http://www.ledsmagazine.com/articles/print/volume-10/issue-2/features/understand-color-science-to-maximize-success-with-leds-part-4-magazine.html
That Imatest MR16 track light setup looks like the way to go for even broad full spectrum lighting. Glad there's a way to plug the rig into a wall. Thanks for the heads up on that, Wayne.
Sigh, with the SOTA for LEDs being what it is, I may go that route also. On the bright side, if Soraa steps their game up a bit, they also make MR-16 lamps so you could swap them out in the same track lighting fixtures.
Wayne
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depends on the track lighting fixtures. some are MR16 and others are BR30 or PAR30 style.
I know that Soraa will be introducing a range of BR30 lamps in Q1 or Q2 of next year but I think they will not be more than 3000-4000K color. So, they can be useful for standard recessed lighting replacement at least.
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This stuff is tricky. I've been trying to improve my understanding of color science by reading books on color science. Color science books are generally treated as college textbooks and are priced accordingly (usually more then $100 (US)). However, I've been able to find earlier editions of these books a lot cheaper.
Wayne, I'm at a loss on what you're trying to derive from color science literature that will help you make a choice on print viewing lighting. I can't make heads or tails from it that provides more information than what my eyes tell me which is what I use to make final judgements on how to make better pictures. Subjectivity and visual adaptation will always be a part of the process which makes all this a moving target. All color science appears to do is to constantly adjust their aim to a standard reference that appears to be needing updating. Where's the consistency in that?
I have to remind myself that R=G=B neutrality on a 6500K calibrated display is an emulation of a reference that is impossible to see and that D50 is suppose to be a comparatively warmer looking reference, another standard that is impossible to see. It's made impossible because daylight changes constantly and so does human visual perception. How close is close enough visually or do we want some scientific instrument to tell us and what if that doesn't give us what we want?
Reproduction work of fine art paintings might benefit from this knowledge, but I find practical application and trial and error processes in this area works a lot quicker, is more informative and more accurate.
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And then there's the online marketing bullshit you have to sift through like this page I found discussing Philips Lumileds Crisp White...
http://www.ledinside.com/showreport/2015/5/led_chip_and_package_trends_at_led_expo_thailand_2015
Scroll down to the photo of the statues. OH?! A camera malfunction? No one on this Earth can find a decent shot of what these lights are suppose to look like? No one has a better camera at a convention in Thailand?!
Are you freakin' kidding me?!
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Still waiting for the commercialization of this invention:
http://news.vanderbilt.edu/2012/05/quantum-dots/
10 years now since the accidental discovery.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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Wayne, I'm at a loss on what you're trying to derive from color science literature that will help you make a choice on print viewing lighting.
You recommended the Soraa bulbs. I got one based on your recommendation and am trying to evaluate it. When I compared it visually with my Solux bulb I could see that the Soraa bulb was way different. So I did some investigating to try to determine what was going on.
Color management is based on color science. It is impossible to avoid color science if you are using color management. You don't need to go whole hog and read the classic color science reference books. But reading articles about the Soraa lamps that you recommended doesn't seem unreasonable.
Wayne
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http://www.ledinside.com/showreport/2015/5/led_chip_and_package_trends_at_led_expo_thailand_2015
Scroll down to the photo of the statues. OH?! A camera malfunction? No one on this Earth can find a decent shot of what these lights are suppose to look like? No one has a better camera at a convention in Thailand?!
You are referring to
(http://p.ledinside.com/led/2015-05/1432722070_81481.jpg)
The caption is
The camera was malfunctioning during this photo shoot, but at the booth it could clearly observed with the naked eye the statue on the right featuring Lumileds Crisp White LED technology was much whiter than the statue on the left. (LEDinside)
I think that "malfunctioning" means that cameras respond differently than eyes do. This is no surprise, but complicates the "color rendering index" problem. We need different methods to measure color rendering for cameras than we need to measure for humans.
Color science is still a work in progress.
Wayne
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Color science is still a work in progress.
Indeed! And a photo of what two bulbs are supposed to look like (and we've seen examples) is rather pointless and not based on color science. You're right to use your eyes as well as measurement devices but the reason why LOOKING at something is more valid than measuring it is because measurement is about comparing solid colors. Color appearance is about evaluating images and color in context which measurement devices can not do.
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You are referring to...
The caption is
The camera was malfunctioning during this photo shoot, but at the booth it could clearly observed with the naked eye the statue on the right featuring Lumileds Crisp White LED technology was much whiter than the statue on the left. (LEDinside)
I think that "malfunctioning" means that cameras respond differently than eyes do. This is no surprise, but complicates the "color rendering index" problem. We need different methods to measure color rendering for cameras than we need to measure for humans.
Color science is still a work in progress.
A bunch of smart technologists on lighting can't figure out how to switch their camera's AWB to Daylight preset on their camera? Ten years ago I bought a Fuji F10 P&S at Walmart and could set it to Daylight preset which clearly showed WB distinctions in its jpeg rendering between even invisible (pinkish) UV spectrum biases in lighting I photographed.
In case you missed my point calling a WB error as a malfunction of the camera peaked my BS radar off the charts. You've got all these smart scientists and technologists and they just can't seem to produce accurate looking photos of their lights. I couldn't find in a Google image search one image showing the look of Philips Lumileds Crisp White LED lighting except the white fabrics compared to off white from regular LEDs. I can't even find a home use bulb for retail sale that has this technology except car headlights. And if it's as blue as I'm seeing in my rearview mirror at night I'm not interested.
There's too much marketing BS hidden by a vale of respectability provided by all this "techy talk" that thinly qualifies as "color science".
Ernst, thanks for that very interesting link on quantum dots. I too wonder why no actual product has come to market after all that research. So they used an acid ants produce to mark their trail to improve luminance efficiency. A story perfect for CBS's 60 Minutes.
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You recommended the Soraa bulbs. I got one based on your recommendation and am trying to evaluate it. When I compared it visually with my Solux bulb I could see that the Soraa bulb was way different. So I did some investigating to try to determine what was going on.
Wayne
Just curious, Wayne, but how different did the Soraa look compared to the Solux? Color of white? Did yellows look greener or reddish?
My issue I had reading those linked LED magazine articles you provided is they don't ask the questions I want answers to and that magazine seems VERY dedicated to this new technology. They write in a way that peaks expectation and interest but deliver very little useable information.
Today I don't have any information that makes me want to buy any of the products they review or analyze. I found out more by just buying and examining the product like the Soraa which is what I've had to do with all the "daylight" lights I've bought for the past 8 or so years researching this.
We're in an information age explosion free to those with an internet connection and I'm having to make the above statement. That makes no sense.
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A bunch of smart technologists on lighting can't figure out how to switch their camera's AWB to Daylight preset on their camera?
I don't think that it is a white balance issue. A global white balance adjustment can't correct part of an image. The author said that the statue on the right looked much whiter than the statue on the left with her eyes. How can you do a global white balance adjustment that would make the statue on the right be white while leaving the statue on the left looking warm?
I think that it is what I said: that cameras work differently than how humans see. Most of the time they are similar enough that it doesn't cause a problem. But sometimes the difference is caught out. I think that these two particular light sources triggered this kind of failure.
I know that my own cameras see differing white balances as being more extreme than how my eyes see them. I use warm "soft white" 2700Kish CFLs and LEDs through most of my house. But use daylight balanced (5000K, I think) bulbs in our kitchen. I can tell the difference when looking at both rooms, but it isn't extreme. But if I, for example, shoot a picture in our living room (2700Kish), any portion of the kitchen that shows will be glaring blue. It doesn't look like this in real life.
Wayne
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We're in an information age explosion free to those with an internet connection and I'm having to make the above statement. That makes no sense.
Color science hasn't caught up with our needs. We need ways to measure color rendering in a way that correlates with how our eyes (and cameras) see. We don't have any such test (yet.)
I just did a test switching between the Soraa lamp, my 4700K Solux bulb, a 120v 90 W 3500 K Solux bulb, and my Home Depot "full spectrum" 5500K CFLs. I was looking at one of Andrew's test prints (http://www.digitaldog.net/files/Gamut_Test_File_Flat.tif) and the Digital Outback Printer Evaluation Image (http://www.outbackphoto.com/printinginsights/pi049/essay.html). All the bulbs looked different. It seems to me that the Soraa lamp exaggerates chroma. Andrew's test image has lots of very saturated colors. Whenever I switched to the Soraa lamp, the saturated colors looked too extreme (similar to looking at an sRGB image on a wide gamut monitor in a non-color managed environment (like the Windows desktop.)) The colors in the Digital Outback image are more restrained so the effect isn't as pronounced. The 4700K Solux bulb seemed the most accurate, followed by the 3500 K Solux bulb. Colors under the CFLs look more muted than any of the other sources.
The Soraa bulb made the whites I saw look whiter than any of the other bulbs did. But I haven't tested whites (OBAs, etc.) as exhaustively as you have, so I can't really make a judgement on whites.
If I was judging prints in earnest, I think that I'd want several of the 12V 4700K lamps with the Plano Convex Diffusers (https://www.solux.net/cgi-bin/tlistore/filterclip.html) (The diffusers are really needed but they reduce the light level such that it is difficult to use a single Solux lamp.) One of the three fixture track lighting fixtures with Solux bulbs that were described on the Imatest site (http://www.imatest.com/docs/lab/) clamped to something would probably work.
The Imatest site doesn't say, but I think that it would be prudent to get the more expensive Solux lamps that have a Black Back. The Solux bulbs radiate unwanted light out the back of the bulb. It isn't good to have the unwanted light reflect off the back of the light fixture. I currently use a Solux black bulb shield on the back of my (non black back) Solux bulb, but it doesn't mount to anything. It just bobbles loose on the back of the bulb. I'm afraid that if the bulb works slightly loose in the socket, that the bulb shield would short across the pins. This would be bad. In the future, I'd go for the Solux bulbs that have the back permanently black.
Yeah, the only way to really judge them is get copies of the bulbs so you can test them with your own eyes. Maybe try one of the 120V PAR Solux bulbs (https://www.solux.net/cgi-bin/tlistore/soluxparbulbs.html).
Wayne
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Wayne, I received my Lavish Desk Lamp, and it is by far the whitest yet pleasing I have around my work area. It is noticeably whiter than the Phillips CFL and Blue Max CFL. I'll be getting some Phillips 100w equiv LEDS in a day or two, so will see how hey match up. Reds look especially good under the Lavish. I wish I had that Argyll color meter to check it. It has that little four tube bulb marked 27 watt.
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The Lavish Desk Lamp competitors on that Amazon page Wayne linked to has reviewers using them to grow plants indoors. And then Lights Of America's version... http://www.amazon.com/dp/B00LG6YVLQ/ref=psdc_1063292_t3_B008E6BQXW
has this claim...
Benefits of full spectrum Lighting: 1) Increases contrast in Reading. 2) Increase release of seratonin a hormone linked to an improved feeling of well being. 3) Increases vitamin D production in skin, which helps the body efficiently use calcium. 4) Render color much more accurately. 5) Reduce levels of melatonin, a harmone that promotes fatigue.
As I recall and I may be wrong but isn't long term exposure to plant growing light dangerous to humans?
I didn't realize there was this many full spectrum desk lamp competitors. Some have over 1000 Amazon reviews.
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I didn't realize there was this many full spectrum desk lamp competitors. Some have over 1000 Amazon reviews.
It's a SAD, SAD, world.
Wayne
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<As I recall and I may be wrong but isn't long term exposure to plant growing light dangerous to humans?>
Turns you into a vegetable, yes.
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We've got a person at work who likes this:
http://fiilex.com/products/V70.php
I'm by no means an expert, but would be interested in thoughts.
I checked out their web site and ended up ordering one. Must say I'm very impressed. Perfect for prints up to 13x19" and fun and useful to see them under different color temperatures. The dimmer is sticky, so easy to match monitor for good screen to print match that comports well with my larger inspection station. This item is great for "sitting next to the monitor" evaluation of proof prints/smaller prints.
Beautifully made as well.
Rand
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I checked out their web site and ended up ordering one. Must say I'm very impressed. Perfect for prints up to 13x19" and fun and useful to see them under different color temperatures. The dimmer is sticky, so easy to match monitor for good screen to print match that comports well with my larger inspection station. This item is great for "sitting next to the monitor" evaluation of proof prints/smaller prints.
Beautifully made as well.
Rand
Does the Fiilex desk lamp render cadmium yellow with a slight green or cyan tint at any color temperature? I noticed Fiilex site's CRI for yellow requires a quite bluish 6500K to render yellow at CRI 96.
What I've noted about overall CRI claims on a wide range of daylight CFL & LED bulbs/tubes' is that it doesn't indicate hue differences which is more noticeable than saturation. Most of the colors viewed under these lights look acceptable except for yellow and WB looking a bit too cyan blue or slightly greenish pastel beige but I've never come across a CRI table that measures and rates each individual color patch as noted on the Fiilex site. For me if cadmium yellow looks as it should under any light that's all I need to know.
$200 for a lamp? Understandable for professionals but not sure it's enticing for hobbyists, but then they're known to spend over $3000 for a lens & camera system. Hope its AC to DC converter holds up better than my discontinued Eiko Solux task lamp.
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Apparently the Argyll PRO ColorMeter will run on Android v4 and later . I already have an i1 Display Pro, so it looks like I could get n RCA 7" tablet running Android 4 something for 45 bucks at Walmart and be able to measure all my lights. This cheap tablet has the microUSB needed. Its resolution is 1080x640 but who cares. I could also get a Nexus 7 for 149 from Newegg that is quite a nice tablet. I'm not happy with my 1st gen iPad anyway. Any thoughts?
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So I am seeing now my Phillips A19 100w equivalent, 5000K bulb side by side with the Lavish desk lamp 6500K fluorescent. The Phillips claims 1500 lumens and the Lavish 1300. i have moderate north light coming in thru a basement window well. Both lamps compare fairly well with the north light. The Lavish is bluer, the Phillips is brighter. I also have a CFL in another desk lamp that is not on but is 3000k and is considerably warmer when I want it. I'm quite pleased with this setup. So pleased that I think I'll go ahead and get something Android to use the Argyll with so that I'll know exactly what I'm seeing.
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Apparently the Argyll PRO ColorMeter will run on Android v4 and later.
Yes. I have ColorMeter (http://www.argyllcms.com/pro/index.html) and it works great. This is what I used to get the spectro plots I put in my posts (http://forum.luminous-landscape.com/index.php?topic=102190.msg843095#msg843095) here.
I use an 8" Samsung Galaxy Tab Pro tablet, but it also works on my wife's discarded Samsung Galaxy III smartphone. The UI is designed to run on a 7" tablet. You can download it and try it on your own device in demo mode (everything works, except that it won't takes any real measurements--it substitutes dummy sample measurements.) You need an OTG adapter (http://www.bhphotovideo.com/c/product/964912-REG/startech_sdcotg_usb_otg_adapter_cable.html) to connect your spectrometer (I use ColorMunki Design).
Highly recommended.
Wayne
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...So pleased that I think I'll go ahead and get something Android to use the Argyll with so that I'll know exactly what I'm seeing.
I missed this line. If you are already using Argyll with a spectrometer, you can get some of what ColorMeter does with Argyll spotread (http://argyllcms.com/doc/spotread.html). Both ColorMeter and spotread will display the spectral plot of whatever you are measuring. Both will give CRI (Color Rendering Index) and CCT (Correlated Color Temperature).
But ColorMeter on a tablet is easier to use and does a lot more than spotread does.
Wayne
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Does the Fiilex desk lamp render cadmium yellow with a slight green or cyan tint at any color temperature?... (snip)
Tim, you are asking all the right questions. But the results from the current eight color CRI test (https://en.wikipedia.org/wiki/Color_rendering_index#Test_color_samples) (most CRI ratings only rest for the first eight pastel colors and don't measure the saturated colors (9-14)) aren't going to tell you the nuances of how cadmium yellow will render.
I'm curious about the Filex lamp too. But not $200 curious. I want to see valid color rendering tests first that answer the same questions that you are asking. Rather than hand wavy endorsements.
If anybody reading this has a Filex lamp, please measure it and publish the spectrum plot. Then we can at least see some hard data.
Wayne
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The future now... ;D
CoeLux http://blogs.discovermagazine.com/d-brief/2015/02/17/led-skylight-authentically-recreates-suns-rays/
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The future now... ;D
CoeLux http://blogs.discovermagazine.com/d-brief/2015/02/17/led-skylight-authentically-recreates-suns-rays/
With the only minor issue being
The only downside for these lights, right now at least, is their price: roughly $61,000 plus $7,000 for installation.
Wayne
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For the CoeLux LED skylight to come out of extensive scientific research and development there sure isn't a lot of scientific data to back up their claims. Google image search of spectral distribution graphs doesn't bring up anything. Hope the light doesn't cause sunburn as someone stated in the comment section. The only way to know is to provide a spectral graph showing how far down into the UV spectrum the light reproduces. Environmental regulators limit it to around 400nm. Anything below that has to have some warnings similar to tanning booths.
I couldn't find the page on their website that states their photos are not doctored. I also find it odd that most of the photos are of wide swaths of blank walled interiors with questionable paint color. The skin tones look good but cadmium yellow objects are missing. Green apples vary in appearance in the amount of cyan (fresher) to orangish yellow (too ripe) which makes them not a good test subject for determining accurate color rendering. I've tried it.
Plastic cadmium yellow objects like a BIC lighter or cleaning product container show the green spike differences under artificial daylight CFL, flotube and LED lighting where the 50 watt Solux 4700K halogen and Soraa 5000K LED render it as close to a sunbeam as possible.
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With the only minor issue being
The only downside for these lights, right now at least, is their price: roughly $61,000 plus $7,000 for installation.
Wayne
We have to wait for a Chinese version... ;D
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Recently made another viewing light for a friend with the same parts I made my own a year or so ago. A recycling shop provided the two lamp houses of a ceiling armature, I bought two GU 5.3 sockets, two Osram Decostar 51 50 watt 12V Cool Blue halogen lamps, in my spare parts archive were two 60 Watt 12 volt transformers and frosted clear PET foil 175 micron for diffusion The output drops just below 4000 Kelvin, continuous spectrum. It stands besides the monitor and shines on a magnetic white board. In the EU the Osram lamps can still be bought I think given several ads, I bought about 20 lamps five years ago, they are cheap. To get 4500 output you will need a somewhat higher transformer voltage, possibly more than 60 watt too. 4000 Kelvin is fine for me and I have two Normlight 5000 K viewing lights too.
The picture has another DIY project too, a data transfer cable + mounts/adapters between a Sigma EF 50 mm macro reversed mounted on a Canon FD bellows with an FD>EF adapter to a Canon 5D MK II. For the lens diaphr. control, Sigma set on manual focus. The concept will drive focusing too if the Sigma is used in its normal position but there are better ideas to start from.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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If you are already using Argyll with a spectrometer, you can get some of what ColorMeter does with Argyll spotread (http://argyllcms.com/doc/spotread.html). Both ColorMeter and spotread will display the spectral plot of whatever you are measuring. Both will give CRI (Color Rendering Index) and CCT (Correlated Color Temperature).
ColorMeter V1.2 and ArgyllCMS V1.8 now support the R9 value to supplement the CRI Ra value (R9 is the saturated Red CRI value, and should be above zero for reasonanble red rendering), and also now display the TLCI (Television Lighting Consistency Index) value.
TLCI is oriented towards TV camera spectral responses rather than Humans, but this may be more like a still camera sensor response, and in any case TLCI is a much more modern standard than CRI, in that it uses a wider set of test colors, and weights the value is a way that makes it hard for the bad rendering of one hue to be hidden in the average.
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I've emailed Aurelien David, Soraa's Chief Scientist from the linked Soraa blog and I'll see what he says.
That's from my August 9th quote. Never got a response.
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Hi Andrew,
I have a question.
Why are you using a Solux lamp to light prints in your Soft-View booth?
Regards
Len
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ColorMeter V1.2 and ArgyllCMS V1.8 now support the R9 value to supplement the CRI Ra value (R9 is the saturated Red CRI value, and should be above zero for reasonanble red rendering), and also now display the TLCI (Television Lighting Consistency Index) value.
Yay! Thanks. I measured a bunch of bulbs today with the new version of ColorMeter. Most noteworthy for this thread is that the Soraa 00807 that we have been discussing has a crazy good TLCI rating (but see comments, below)
(http://pics.fishcreekstudio.com/Other/Spectrum-11/i-KJLt9jj/0/M/0009_Screenshot_2015-08-21-16-26-32-M.jpg)
But the 12V Solux 4700K bulb is still (sigh) better.
(http://pics.fishcreekstudio.com/Other/Spectrum-11/i-jmTctVD/0/M/0007_Screenshot_2015-08-21-12-12-41-M.jpg)
The 120 V 3500 K Solux Par 38 lamp doesn't measure too bad, but the 12V one is still better.
(http://pics.fishcreekstudio.com/Other/Spectrum-11/i-3kvTWSc/0/M/0008_Screenshot_2015-08-21-12-17-31-M.jpg)
All the more conventional CFLs and LEDs had worse TLCI measurements than their CRI measurements. Most of the "no CRI listed" CFLs and LEDs had real terrible R9s.
One anomaly is that the Soraa 00807 only measured CRI 88.6 but it is rated as being CRI 95. None of the other lamps I measured measured worse than their manufacturer's ratings. And I don't think that any had a TLCI that was higher than the CRI95.
Here are the bulbs I measured today (http://pics.fishcreekstudio.com/Other/Spectrum-11/51471151_sppwNq). Let me know if I made any errors with the annotations.
Wayne
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Could you please identify your charts. I can't believe Color Meter doesn't allow you to insert the name of the item you are measuring.
I just got a NextBook tablet from Walmart for fifty bucks. Runs Android 4.4, 7 inch screen 32 GB, fast processor. When I finally get Google to stop asking me questions and destroying my other email accounts, I may be able to measure all my lamps with my i1 Display Pro. It only took Dell nine months to verify that their idiotic read me file in the Dell UltraSharp Color Calibration Solution did not mean that MY Mac would crash, so I never got around to calibrating my Dell U2413 and the Display Pro has been sitting there wondering if I would ever fondle it.
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what he measured is labeled under the large version of the image - is that what you were looking for?
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(...)It only took Dell nine months to verify that their idiotic read me file in the Dell UltraSharp Color Calibration Solution did not mean that MY Mac would crash, so I never got around to calibrating my Dell U2413 and the Display Pro has been sitting there wondering if I would ever fondle it.
Try the updated version, works for UP2715K/UP3214Q/UP2414Q/U3014/U2713H/U2413.
http://www.dell.com/support/home/bg/en/bgdhs1/Drivers/DriversDetails?driverId=1T7VK
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Could you please identify your charts.
Sorry. The labels are above each chart. The top one is the Soraa; the middle one is the 12V 4700K Solux; and the bottom one is the 120V 3500K Solux.
Wayne
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I just got a NextBook tablet from Walmart for fifty bucks. Runs Android 4.4, 7 inch screen 32 GB, fast processor. When I finally get Google to stop asking me questions and destroying my other email accounts, I may be able to measure all my lamps with my i1 Display Pro.
The i1Display Pro is a colorimeter and can't do spectral measurements. (CRI and TCLI are spectral measurements.) See the ColorMeter instrument capabilities chart (http://www.argyllcms.com/pro/cmdoc/instrument_capabilities.html).
ColorMunki Design and ColorMunki Photo are the cheapest spectrometers.
Wayne
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Try the updated version, works for UP2715K/UP3214Q/UP2414Q/U3014/U2713H/U2413.
http://www.dell.com/support/home/bg/en/bgdhs1/Drivers/DriversDetails?driverId=1T7VK
Thank you very much for that update. It is so difficult to find that page by going to the Dell site that I had to ask X-Rite how to do it the first time.
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what he measured is labeled under the large version of the image - is that what you were looking for?
Please see Wayne Harmon's reply to understand why I asked.
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The i1Display Pro is a colorimeter and can't do spectral measurements. (CRI and TCLI are spectral measurements.) See the ColorMeter instrument capabilities chart (http://www.argyllcms.com/pro/cmdoc/instrument_capabilities.html).
ColorMunki Design and ColorMunki Photo are the cheapest spectrometers.
Wayne
Not sure what you mean. The i1 Display Pro colorimeter is one of the compatible instruments, and I want to measure my lamps just as you did.
I opened the DEMO on my Android and looked at the various examples, and I am about to hook up my i1 with a USB To Go cable to see what happens.
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Not sure what you mean. The i1 Display Pro colorimeter is one of the compatible instruments, and I want to measure my lamps just as you did.
I opened the DEMO on my Android and looked at the various examples, and I am about to hook up my i1 with a USB To Go cable to see what happens.
You won't be able to measure lamps like I did with an i1 Display Pro colorimeter. "Compatible" means that ColorMeter will work with an i1 Display Pro. But "compatible" doesn't mean that all ColorMeter features will be available. This is explained in the ColorMeter documentation, if you dig deep enough. See ColorMeter doc page for the lighting tests (http://www.argyllcms.com/pro/cmdoc/P_Lighting.html) It says
Measure the Illuminance, Correlated Color Temperature and Color Rendering Index (CRI) & Television Lighting Consistency Index (TLCI) of an illuminant.
A spectrometer type instrument is needed to compute the CRI. (Emphasis added)
See the doc page for the spectral graph (http://www.argyllcms.com/pro/cmdoc/spectral_graph.html):
The spectral graph is only available for measurements that have spectral measurement information, and this is only possible from spectral measurement instruments.
and then references the Instrument Capability (http://www.argyllcms.com/pro/cmdoc/instrument_capabilities.html) page.
With a i1 Display Pro, you can measure the CCT (color temperature). You can also use most (or all) of the features in the Photography Preset (http://www.argyllcms.com/pro/cmdoc/P_Photography.html), which is a nifty light meter/color meter. This can be handy if you want a light/color meter (say, if you are using gels to balance light temperatures.)
I already have an i1 Display Pro and I use it to calibrate my monitors. But you need a spectrometer type instrument to make spectrum plots like I did. I bought my ColorMunki Design (http://www.bhphotovideo.com/c/product/555132-REG/Pantone_MEU115_ColorMunki_Design_Color_Management.html) expressly so I could do those measurements. And as an incentive to learn more about color science.
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Thanks for the explanation. All I want is the color temperature, CRI is too ambiguous anyway.
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well, i found an expensive lamp: http://arcadianhome.com/LS-2037-PS i emailed the company who makes it and they pointed me to this retailer. (EDIT, i emailed them the link to the solux mr16 bulbs and this is what they said would work with it) i've ordered it and a couple of solux non-black bulbs + diffuser. the price of the lamp doesn't irk me as much as the 50% of total order price for shipping. really? solux doesn't offer any information or help when it comes to some type of free standing desk light and the shipping charge is 1/2 the cost of 2 bulbs and a diffuser. $15 shipping $30 bulbs/diffuser. i know i shouldn't complain because i did it, but i will :) anyway, they must just do big commercial projects and probably do consumer stuff because enough people bugged them.
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If you've ordered the non-black Solux you may find you need to paint the inside of the lamp housing black. I have the non-black Solux in ordinary flush down-light fittings and I found that the light leaving the back of the Solux was being reflected back through the lamp and "contaminating" the forward beam, reducing the colour temperature.
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pardon the late update! i got the lamp and the solux bulbs. lost the diffuser somewhere - it didn't have it's own box. wouldn't have worked because turns out i need the frame to attach it.
anyway... 50 watts is WAY to bright for a desktop lamp. i mean wow. looks good though! prints look awesome. the ott light just isn't as rich looking or something.
the lamp i have definitely has an open back, it's surprising to see how yellow the light is coming out the sides/back.
i'm going to go ahead and order the 4700k 35watt and diffuser. i'm not sure how that's going to work... the diffuser has a black shield that allows you to attach it over the bulb. i'm guessing it will work just like the black bulbs would work? just in case i think i'll order the black bulbs. i might try the 3500k too. i have one but it's 50w and i haven't tried it yet, i'll do that this week.
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I have an update on this. The lamp I referenced above has an interesting way to mount the bulb. The bulb attaches to the socket on the top side (back side) of a ring. the bulb then shines down through the ring onto the desk. The back side of the bulb is exposed and leaks light (so I did order the black backs).
I just received my two 4700k 35watt bulbs and it is MUCH better in that it's not blindingly bright like the 50watt. I also got the black back bulbs.
The opening in the ring of the lamp is perfect size to first drop in the diffuser, curved side facing down towards the desk. Then the socket and bulb can slide down on top of that at an adjustable height. My only concern is whether or not there should be a gap between the diffuser and the rim of the bulb for heat purposes? I'll email solux about that.
I'm REALLY liking this lamp although it's not as tall as I would like it, but it's working out very nicely with the black back mr-16 bulbs!
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I've attached a photo of the lamp head/socket with the diffuser and black back bulb.
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how tall is it?
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19" from my desk to the top of that little flexible electrical line. at that height, it puts the bottom of the lamp ring at 16" off the desk. if you tilt the lamp forward fully (which means moving the head assembly further out over the desk) the lamp ring is 14.5" off the desk. you can't tilt it forward too far.
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i just tried a spotread via argyllcms and colormunki. spotread -a. these are the results. the diffuser might have something to do with the CCT being less than 4700 (unless i need to let the lamp warm up?) and honestly i'm not exactly sure i'm doing the ambient light reading correctly. also, that mounting ring could be coloring the light due it the bulb being reflected on the inside edges.
Result is XYZ: 3661.682140 3776.785013 2606.918954, D50 Lab: 373.193350 3.080063 38.701747
Ambient = 3776.8 Lux, CCT = 4454K (Delta E 6.691731)
Suggested EV @ ISO100 for 3776.8 Lux incident light = 10.6
Closest Planckian temperature = 4324K (Delta E 5.473168)
Closest Daylight temperature = 4412K (Delta E 2.011641)
Color Rendering Index (Ra) = 96.4
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I have been surprised that the OTTLITE has not been mentioned in this forum. I find the light a very pleasing addition to my desktop and as it is very reasonably priced in Costco Canada it would likely be much cheaper in the US. It has three levels of brightness 766 Lux @ 5219 K, 308 lux @ 5211K ,and 81 Lux @ 5195 K. Measured by I1Pro 11 and Babelcolor CT& A the spectrum seems reasonably flat and the more detailed specifications are in the attached
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the spectrum seems reasonably flat
does that look "reasonable" ?
(http://s8.postimg.org/d1ja2msqt/flat.jpg)
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the CCT being less than 4700
voltage...
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I have been surprised that the OTTLITE has not been mentioned in this forum. I find the light a very pleasing addition to my desktop and as it is very reasonably priced in Costco Canada it would likely be much cheaper in the US. It has three levels of brightness 766 Lux @ 5219 K, 308 lux @ 5211K ,and 81 Lux @ 5195 K. Measured by I1Pro 11 and Babelcolor CT& A the spectrum seems reasonably flat and the more detailed specifications are in the attached
What about the Fiilex V70 Color Viewing Lamp? There are 3000K, 4000K, 5000K, and 6500K color temperature selections. It has a CRI greater than 90, whatever this means. And it can be continuously dimmed from 100% to 25% of its light intensity. This viewing lamp also has a diffuser dome attachment. This costs a whole $195 from B&H. I have not measured this with my i1Pro yet. Oh yes, the description states it is good for 50,000 hours of light.
It may not be as accurate as a viewing booth, but it appears to give me an idea of how the print will change with each setting.
Bob
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What about the Fiilex V70 Color Viewing Lamp?
datasheet with spectrums = http://fiilex.com/pdf/Fiilex_V70_DataSheet.pdf
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datasheet with spectrums = http://fiilex.com/pdf/Fiilex_V70_DataSheet.pdf
Thanks for the link!
The lamp has a CRI, on the average, of over 90. I would think that this should make it accurate enough for my purposes. But there are some problem areas, particularly with R9 on their chart, deep red, and R12, deep blue. Interesting. I am not sure this is a good thing. Since the color temperature spectrum goes from more predominantly blue to yellow to more predominantly red, the color lamp is perhaps not that accurate for photo use at the extremes.
I wonder how this will effect real world use of the lamp? I would think that the red and blue components of the spectrum of each temperature would be paramount to its accuracy for use by photographers. At each of its color temperatures, both the blue component and the red component have a CRI well below 90, closer to 70. Most of my use will be toward the blue end of the color temperature spectrum. I wonder where this places the visual accuracy of D65?
This does not make any sense. Why should such a lamp be constructed in this way? What do you think? Perhaps this lamp will only give me an idea of how the photo will change in differing color temperatures. But accurate inspection may only be possible using a different method. So that relegates this lamp to be used for educational purposes.
Bob
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does that look "reasonable" ?
(http://s8.postimg.org/d1ja2msqt/flat.jpg)
Is this a graph of the frequency spectrum for the given light temperature of the lamp? I would not expect the frequency spectrum at a given temperature to be flat. As you move from red to yellow to bluish light temperatures, there is a dominant frequency of color. So there should be the appropriate "spike". But that significant dip and rebound after the "spike" appears to be a problem area.
I am probably thinking about this in the wrong way. :(
As a side note, I wonder if the difference between 5000K and D50 is the actual color spectrum for that temperature of light. While there can be different color spectrums for a 5000K light, D50 specifies one particular color spectrum map for that temperature of light? Interesting. So that makes 5000K represent a Correlated Color Temperature? Sorry guys!
Andrew? :)
Bob
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So there should be the appropriate "spike".
check solux and try find there such "spike" as you have here
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The Lavish 6500K 1399 lumen lamp I bought last month has a four tube bulb. I liked it a lot until the bulb failed today. I'll probably replace the bulb once and if it doesn't last I will try to return it.
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check solux and try find there such "spike" as you have here
Thank you for pointing this out.
Perhaps "spike" is the wrong term. Perhaps there really should not be an actual spike. Perhaps a more subtle "peaking" at the color which represents the color temperature in question? I saw a frequency map of a Solux light during my search. There appeared to be a curve that ramped up and peaked through a smaller range of values and then fell back a bit. What do you think? Am I seeing things? LOL Daylight is not perfectly white. It tends toward the blue, correct?
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What do you think?
I suggest this = http://forum.luminous-landscape.com/index.php?topic=100698.0 ( and this post with graphs = http://forum.luminous-landscape.com/index.php?topic=100698.msg830255#msg830255 from that topic )... Solux is not the ideal solution some people here will say, but its SPD looks better than the LED you are suggesting... however that might be OK for your purposes
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And this is what the Ottlight spectra does to OBA distinctions in paper vs the Solux. The Ottlight is great for hiding OBA's in paper but at the sacrifice of color accuracy.
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I did not think of this aspect of the lamp that I have suggested. It looks like I will have to find a light that provides a good representation of daylight for my own purposes.
PS: As I suspected, the chromaticity at D65 is way off. Even the Correlated Color Temperature (CCT) is off at 6347K. The other light settings are off, but IMO close enough for my purposes for now. I will eventually have to get a light viewing booth when I get into making fine art prints, one that includes UV for its D50 setting. I guess you get what you pay for. And the advertised CRI does not tell the whole story, particularly when UV is involved. FWIW I used the ISO 3664+ from BabelColor for my measurements and evaluation.
Bob