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Author Topic: Choosing a new desk lamp for digital processing.  (Read 75109 times)

WayneLarmon

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Re: Choosing a new desk lamp for digital processing.
« Reply #80 on: August 14, 2015, 10:21:17 pm »

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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 (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
« Last Edit: August 14, 2015, 10:24:42 pm by WayneLarmon »
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Pictus

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« Last Edit: August 14, 2015, 10:36:18 pm by Pictus »
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WayneLarmon

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Re: Choosing a new desk lamp for digital processing.
« Reply #82 on: August 15, 2015, 08:54:10 am »

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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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Tim Lookingbill

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Re: Choosing a new desk lamp for digital processing.
« Reply #83 on: August 15, 2015, 04:22:47 pm »

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.
« Last Edit: August 15, 2015, 04:30:04 pm by Tim Lookingbill »
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Pictus

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Re: Choosing a new desk lamp for digital processing.
« Reply #84 on: August 15, 2015, 07:17:59 pm »

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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Ernst Dinkla

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Re: Choosing a new desk lamp for digital processing.
« Reply #85 on: August 16, 2015, 08:38:32 am »

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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GWGill

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Re: Choosing a new desk lamp for digital processing.
« Reply #86 on: August 20, 2015, 08:24:30 am »

If you are already using Argyll with a spectrometer, you can get some of what ColorMeter does with Argyll spotread.  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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Tim Lookingbill

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Re: Choosing a new desk lamp for digital processing.
« Reply #87 on: August 20, 2015, 02:28:50 pm »

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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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LenR

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Re: Choosing a new desk lamp for digital processing.
« Reply #88 on: August 21, 2015, 02:05:28 pm »

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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WayneLarmon

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Re: Choosing a new desk lamp for digital processing.
« Reply #89 on: August 21, 2015, 06:46:32 pm »

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)



But the 12V Solux 4700K bulb is still (sigh) better.



The 120 V 3500 K Solux Par 38 lamp doesn't measure too bad, but the 12V one is still better.



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.  Let me know if I made any errors with the annotations.

Wayne
« Last Edit: August 21, 2015, 08:32:44 pm by WayneLarmon »
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Lundberg02

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Re: Choosing a new desk lamp for digital processing.
« Reply #90 on: August 21, 2015, 10:45:47 pm »

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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sgwrx

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Re: Choosing a new desk lamp for digital processing.
« Reply #91 on: August 21, 2015, 11:12:04 pm »

what he measured is labeled under the large version of the image - is that what you were looking for?
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Pictus

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Re: Choosing a new desk lamp for digital processing.
« Reply #92 on: August 22, 2015, 12:05:25 pm »

(...)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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WayneLarmon

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Re: Choosing a new desk lamp for digital processing.
« Reply #93 on: August 22, 2015, 01:34:03 pm »

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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WayneLarmon

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Re: Choosing a new desk lamp for digital processing.
« Reply #94 on: August 22, 2015, 01:59:10 pm »

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.

ColorMunki Design and ColorMunki Photo are the cheapest spectrometers. 

Wayne

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Lundberg02

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Re: Choosing a new desk lamp for digital processing.
« Reply #95 on: August 22, 2015, 07:11:10 pm »

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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Lundberg02

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Re: Choosing a new desk lamp for digital processing.
« Reply #96 on: August 22, 2015, 07:12:32 pm »

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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Lundberg02

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Re: Choosing a new desk lamp for digital processing.
« Reply #97 on: August 22, 2015, 07:17:02 pm »

The i1Display Pro is a colorimeter and can't do spectral measurements.  (CRI and TCLI are spectral measurements.) See the ColorMeter instrument capabilities chart.

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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WayneLarmon

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Re: Choosing a new desk lamp for digital processing.
« Reply #98 on: August 22, 2015, 09:48:07 pm »

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  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:

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 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, 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 expressly so I could do those measurements.   And as an incentive to learn more about color science.
« Last Edit: August 22, 2015, 09:59:29 pm by WayneLarmon »
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Lundberg02

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Re: Choosing a new desk lamp for digital processing.
« Reply #99 on: August 23, 2015, 10:48:31 pm »

Thanks for the explanation. All I want is the color temperature, CRI is too ambiguous anyway.
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