Evaluation of BenQ desktop LED lamp for print viewing booth

[Louie]

I am curious has anyone here evaluated this lamp as a potential light source for a print viewing booth? My previous viewing booth was an easel and a Solux desktop task lamp. Unfortunatly that has broken in two and is no longer in production. And a fruitless search has failed to locate any desk task lamp using MR16 bulbs.  The are all LED with unknown quality.

The BenQ e-Reading lamp has some promising features especially adjustable color temp and a CRI 95, however, it still could have problems in the spectral curve that could make it unusable for print evaluation.

-louie

[digitaldog]

Ignore CRI, nearly meaningless. Its a bit of a kludge to make a light source appear to be closer to daylight for marketing and light manufacturers. CRI was developed in large part to aid in the sales of Fluorescent tubes. There are BCRA tiles used to compare under a reference light source but 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 48 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.  A better metric is called CQS (15 very colorful patches). That doesn't tell us about the spectrum which is even a better way to evaluate the illuminant. 

[Czornyj]

I'm using custom made MR20 LED bulbs with TRI-R SunLike LED (violet emitter with R,G,B phosphors), it's perfect for print evaluation (97% CRI-14 and CQS Qa)

http://www.seoulsemicon.com/en/technology/sunlike/

[JRSmit]

I have a set of high cri Vic led 5000k on metal strips from yujiintl, looking for some time to install, and compare with my current high cri fluorescent tubes .

[Louie]

That doesn't tell us about the spectrum which is even a better way to evaluate the illuminant. 

Right, so probably necessitates purchasing the lamp and measuring the spectrum which could be done with BableColor CT&A and my i1Pr02.  I was hopping that perhaps someone here had already done that.

Back to plan A build a light booth making use of the two goose-neck, clamp on MR16 fixtures I found in storage.

-louie

[digitaldog]

You get me the lamp, I'll measure it and send it back. Otherwise, I can't comment on that specific lamp, other than again suggesting that their CRI spec means little.
One has to wonder why manufacturers don't provide a spectral plot....

[PhilipCummins]

Right, so probably necessitates purchasing the lamp and measuring the spectrum which could be done with BableColor CT&A and my i1Pr02.  I was hopping that perhaps someone here had already done that.
Back to plan A build a light booth making use of the two goose-neck, clamp on MR16 fixtures I found in storage.

You could probably ask a reseller like Image Science or a local reseller who specialises in colour management to see if they can quickly get a SPD reading from the lamp to see if it fits your requirements?

[Richard.Wills]

I'm intrigued by the bias and desk lights from Medialight.

If my understanding is correct, then motion picture colour grading is every bit as serious (and then some) as print workflow. These are being sold via Flanders Scientific, the cost of whose monitors make Eizo look like pocket change.

[Czornyj]

I'm intrigued by the bias and desk lights from Medialight.

If my understanding is correct, then motion picture colour grading is every bit as serious (and then some) as print workflow. These are being sold via Flanders Scientific, the cost of whose monitors make Eizo look like pocket change.

There's an adaptation difference between same CCT broadband (full spectrum LED) and narrowband (display) stimuli that makes display white look warmer, so in practice a D65 LEDs will look too bluish. A 5000-5500K LED gives much better match.

[Louie]

You get me the lamp, I'll measure it and send it back. Otherwise, I can't comment on that specific lamp, other than again suggesting that their CRI spec means little.
One has to wonder why manufacturers don't provide a spectral plot....

Thanks Rodney,

If I decide to get one I'll just get BableColor for my own and measure it myself.

CRI is interesting in that a good quality daylight light source will have high CRI but a high CRI doesn't mean a flat curve spectrum. Great marketing tool though. But as you said good enough for household use.

The current crop of LED bulbs are way better that the original ones that made it to market. I tried some a number of years ago and they were ghastly green/blue. Even worse than the CFLs of the time. I now have a bunch of Soraa PAR20 bulbs in my downstairs. They are quite pleasant. However,  Soraa doesn't provide spectral curves either so you don't know what's lurking there.

The Solux MR16 bulb is the best but the LED explosion has killed the market for MR16 fixtures. (sigh) Only track and rail systems are available.

-louie

[digitaldog]

Great call; awesome piece of software.

[Richard.Wills]

There's an adaptation difference between same CCT broadband (full spectrum LED) and narrowband (display) stimuli that makes display white look warmer, so in practice a D65 LEDs will look too bluish. A 5000-5500K LED gives much better match.

Thanks Marcin, I should have spotted that. Looking for a small lamp to go in my grey space... Now to find a 5000K light, to go with the GTI graphic tubes.

[Czornyj]

Thanks Marcin, I should have spotted that. Looking for a small lamp to go in my grey space... Now to find a 5000K light, to go with the GTI graphic tubes.

https://store.yujiintl.com/collections/standard-illuminant/products/standard-illuminant-cri-98-d50-5000k-t8-led-tube-pro-iso3664-2009

[TechTalk]

My previous viewing booth was an easel and a Solux desktop task lamp. Unfortunatly that has broken in two and is no longer in production. And a fruitless search has failed to locate any desk task lamp using MR16 bulbs.  The are all LED with unknown quality.

You might want to take a look at the Fiilex V70 viewing light. B&H sells it for $195 and there are several end user reviews there. The light is continuously dimmable and has four CCT settings of 3,000, 4,000, 5,000, and 6,500 K. It produces a hard direct light or comes with a magnetically attached diffusion dome.

I have no personal experience with their viewing light. If it's returnable, should it be unsatisfactory for you, it might be worth trying. I have rented Fiilex LED lights for video and still photography on occasion and liked their engineering, features, and light quality and found them quite useful for some applications.

Their LED technology is unique to Fiilex. They engineer and manufacture their own LEDs into what they call a "dense matrix" array. It essentially consists of a large number of tiny LEDs with differing spectral characteristics packed together in a very small matrix array with several addressable color channels within the array. The array in their first light had 50 multi-spectrum LEDs in a matrix the size of a dime. They attracted a lot of attention in the video world, when their first lighting products hit the market, due to producing a hard LED optical light source which differentiated them from the broad LED light panels that had been commonly used.

If anyone is interested in the background technology, I found a couple of YouTube videos with a Fiilex engineer giving basic descriptions of the concepts involved.

https://www.youtube.com/Fiilex's Unique LED Technology

https://www.youtube.com/Fiilex's 192-Point LED Calibration Process

One purchaser on Amazon did post some photos of his own spectral measurements. I also discovered that there are people who are very serious about measuring the color of wine! The author of the wine color measuring research paper, Mark Fairchild at the Program of Color Science/Munsell Color Science Laboratory, Rochester Institute of Technology, mentions the Fiilex V70 at the bottom of the article in the conclusion (#3) section. He also includes this table in the conclusions section which gives CCT measurements along with TM-30 scores for fidelity and gamut. (I don't know how Andrew feels about the ever evolving TM-30 color reference standard)

[TechTalk]

I'm intrigued by the bias and desk lights from Medialight.

If my understanding is correct, then motion picture colour grading is every bit as serious (and then some) as print workflow. These are being sold via Flanders Scientific, the cost of whose monitors make Eizo look like pocket change.

The MediaLight Desk Lamp is only intended as a task lamp for lighting the keyboard and console areas when doing video color grading. It isn't designed for color comparison.

Since D65 is the standard for video color grading, it's just meant to light work areas on the desk with a complimentary CCT task lamp to avoid the color difference distraction that say a tungsten balanced task light might produce. It appears to work well for that purpose.

They also make similar bias lighting used behind the display to reduce eyestrain in dark editing rooms. The same type of bias and task lights are used in dark medical diagnostic reading room environments.

[Louie]

You might want to take a look at the Fiilex V70 viewing light. B&H sells it for $195 and there are several end user reviews there. The light is continuously dimmable and has four CCT settings of 3,000, 4,000, 5,000, and 6,500 K. It produces a hard direct light or comes with a magnetically attached diffusion dome.

One purchaser on Amazon did post some photos of his own spectral measurements.

Thanks for the additional sleuthing. Looks like a nice option for a desk lamp. However based on the spectral plots provided by the Amazon reviewer the blue spikes are quite prominent at all settings especially the higher CCTs that one would be using for print evaluation.

-louie

[TechTalk]

I was kind of hoping that you might try one out and give us your visual assessment. The online reviews are generally favorable, but not very detailed. I saw the one blue spike which is not uncommon to see in LED SPD graphs. Often in LED or fluorescent SPD graphs there are multiple spikes and valleys, including lights in the standard viewing booths that are widely used. It isn't a SoLux, but I was just hoping to get a set of critical eyes on the light in real world use to give some visual comparison and feedback. Perhaps we'll eventually find a volunteer to do that to add to the one set of user generated SPD graphs and multiple online reviews.

[Louie]

I was kind of hoping that you might try one out and give us your visual assessment. T

Ha! That's what I was hoping that you would do...

I'm leaning towards the BenQ for two reasons. 1) long articulated arm like the old architect lamps. And 2) the really wide beam spread.

Years and years ago I had one of those fluorescent desk lamps with probably a 12" pair of tubes. Other than all the problems with fluorescent light source it has the best coverage of the workspace of any desk lamp that I've ever owned. Even the Solux task lamp with the wide diffuser had annoying small coverage.

I haven't ordered on yet but if and when I do I promise post back my observations.

-louie     

[MfAlab]

Waveform lighting has some good LED lightings. https://www.waveformlighting.com/

They show you SPD and TM30 data, not just CRI Ra. And they have color comparison standard light called ABSOLUTE SERIES. If you want to build a DIY light booth, it's a great choice.

[Arlen]

I'm using custom made MR20 LED bulbs with TRI-R SunLike LED (violet emitter with R,G,B phosphors), it's perfect for print evaluation (97% CRI-14 and CQS Qa)

http://www.seoulsemicon.com/en/technology/sunlike/

Marcin, can you give us more detailed information about which products you bought and how you set this up? The Sunlike website you linked to has a lot of different products, and it's not clear (to me anyway) how one would proceed to set something up like you have.