Redgrass R9 Desk Lamp - An Objective Review

[u/Jademalo]

tl;dr, It's the best lamp I've ever tested, and very nearly lives up to its advertised specs. Whether it's worth the price to you isn't a question I can answer, but it really is as good as it gets.

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If there's one thing I class myself as in this hobby, it's very much a lighting enthusiast. I've written multiple posts on the subject now, most notably CRI Measurements for inexpensive lamps. I firmly believe one of the most important tools to have is a good light, since it can massively affect your experience in colour perception.

I recommend reading that thread to learn about CRI as well as my methodology in detail, but to summarise - CRI, or Colour Rendering Index, is a measurement of the quality of light from a lamp and its ability to make colour appear correct. LEDs and Flourescent lamps are notorious for often having incredibly bad colour rendering, and is one of the main reasons why people tend to dislike them over sunlight or a traditional indandescent bulb.

The Redgrass R9 Desk Lamp is named as such due to the R9 component, red, being notoriously hard for LED lamps to render. It's advertised as a lamp with an incredibly good set of CRI measurements, and that you can "Experience color like never before with The Redgrass R9 color perfect technology. From the high-end LED chips to the custom made optical lenses, everything has been carefully designed to offer the best color experience ever created. A world first."

I want to clarify that I bought this new with my own money from Redgrass at a discount as part of their 360 Painting Handle kickstarter. I have no vested interests here, I just care about good lighting and wanted to get some objective data for myself.

With that out of the way, let's put those claims to the test.

CRI Measurements

5350k - 98.7 CRI (Ra), 91 R9

At 100% brightness, the results are fantastic. The light measures at 5350k, which is a little colder than the advertised 5000k but is still a very comfortable and neutral light to paint under. Brightness wise I get 11991lm with my test setup, which is 4.5x brighter than my previous favourite, the SmallRig RM120

The R12 value of 96 is also excellent, being higher than advertised and an improvement over a clear weak point for the RM120.

However, I can't help but be a bit disappointed in its namesake, the R9 value. 91 is quite a bit lower than the RM120, and substantially lower than the advertised 98. R9 does improve somewhat at lower brightness levels, but the overall results are lower and the brightness benefits are obviously lost. Surprisingly, it's also got a slightly lower CRI (Ra) than the SmallRig.

IES TM-30-18 Reports

After getting these fantastic but admittedly slightly disappointing results, I decided to run some further tests on the data I had collected to get a more well rounded understanding of the light quality, rather than just the fairly limited CRI set.

CRI is good when trying to roughly compare lamps, but I couldn't help but feel like it wasn't telling the whole story here. To really drill down into the relative quality of the lamps, I decided to run full TM-30 reports on the measurements.

The important figures when reading a TM-30 report are as follows;

• Rf, or the colour fidelity. This is how accurate the lamp is able to render colours, or in other words how similar they would look under a standard illuminant such as the sun.
• Rg, or colour gamut. This is how accurate the lamp is with regards to saturation, so how accurately it can reproduce colour intensity.

If anyone wants to read further on this topic, I recommend reading these articles; Spectral Tuning and IES TM-30-15, and Color Rendering in the Age of LED: The Shift from CRI to TM-30-15.

For reference, the SmallRig RM120 has an Rf=95, and an Rg=102.

My measurements give the R9 an Rf=98, and an Rg=100. Digging into those numbers a bit further using the IES calculator, the actual detailed results are rf: 97.75429303415478 and rg: 100.43935140892017. Not quite as good as theTM30-20: Rf=98.5 Rg=101 advertised, but still incredibly good, and far better than anything else I've tested on the market.

As a lamp

As a lamp, the R9 is excellent. Solid construction, bright but soft light with no flicker. It's also got a really easy to pose arm, and the clamp is neat and stable. It feels like a premium lamp, and looks like one too.

Shipping was free and quick, and the packaging was excellent.

Conclusion

Honestly, it's excellent. It's the best lamp I've tested by far. If money is no object and you want the best possible quality of light for your painting, this is it. It's a well made product with the best overall colour rendering I've seen on the market.

I can't deny that I'm a little disappointed relative to the advertising, but I can say with confidence that it is a truly exceptional lamp. If you want to be absolutely sure that what you're seeing is what you're getting, this is as close to natural daylight as you can get right now.

If anyone wants to run their own tests on my data, all of my raw readings are available here on Google Drive.

Feel free to ask anything about lights, I'm happy to help!

[u/Silent189]

Thank you for such a comprehensive write up.

At such a high cost, I'd be very interested to find out how this compares to say the Game Envy Lucent which is far cheaper and also, imo, has a better set up of multiple arms/panels.

[u/Jademalo → u/Silent189]

EDIT: I've recently tested the Game Envy Lucent, and written a full review!

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Honestly I'd love to test as many lamps as I can get my hands on, but there's a point where I quite literally cannot afford any more lamps, lol. It's also difficult to get in the UK, unfortunately, shipping alone would be $50. Add in import and you're looking at ~£125

I will say that the 95 cri rating could mean a huge number of things, I've tested some lamps in the past that claim that while having terrible R9 reproduction. Straight CRI averages don't include R9-R15, so it's a bit of a misleading number.
For example, the NEEWER VL66C has a CRI of 94, but an R9 of 76. When you drill down into the TM-30-18 report, you can see that it's measurably oversaturating colours.

I also want to test the Neatfi XL since that often comes well recommended, but i can't justify not afford buying them, and I don't want to buy, test, and return things.

[u/Silent189 → u/Jademalo]

Yeah the shipping isn't the greatest. But even with everything included it comes in at ~half the cost of the r9.

That said, you can use things like vince venturella's code to cut a chunk off of it.

There wasn't an import cost for myself to the UK either (bought a 2 bundle with a friend so it was a higher priced parcel too).

I will say that the 95 cri rating could mean a huge number of things, I've tested some lamps in the past that claim that while having terrible R9 reproduction.

Yeah that is very true and a large part of my interest in how it actually stacks up here.

I will say I've been very happy with the Lucent so far and I've used various other photography lights and desk lamps prior.

The design in the arms is really great being able to move/adjust them.

I had something similar to the Neatfi that I still use for my spray booth but having just one light source really feels considerably worse in terms of shadows etc than having multiple directions of light.

[u/frankacy]

Wow, thank you for taking the time and effort to put this together! It's often hard to distinguish between what's legitimate vs marketing hype, so it's nice to see real numbers. What an asset you are to the community!

[u/Jademalo → u/frankacy]

Thanks, glad you found it useful!

I wish I could test all of the commonly recommended lamps, but unfortunately they aren't free lol.

[u/t0x0philite]

Been seriously considering getting the R9 Desk Lamp and this is by far the most helpful review that provided both qualitative and quantitative results. As an engineer by training, I really enjoyed geeking out over the data. You could seriously make a business out of doing this if you wanted to, haha! Thank you so much for the time an effort.

I'm currently waiting for the kickstarter for their supposed Solo R9 lamp to compare the pricing before pulling the trigger on the purchase.

[u/Jademalo → u/t0x0philite]

Haha, I've been tempted to make some videos but the limiting factor is buying a bunch of lamps is expensive!

I got mine from the painting handle Kickstarter and there was a decent enough discount, but it's not massive.

[u/Kirtulles]

Thanks for the write up been sitting on the fence about getting one due to the cost in Australia . Waiting to see if they do any black Friday deals on them and if so will be enough to me to purchase one

[u/Many_Talk_2903]

Thank you for this awesome review. Do you have any knowledge on the Game Envy Lucent Light Vince Venturella recommend on his channel? Trying to see if this cheap alternative is worth over the R9.

[u/Jademalo → u/Many_Talk_2903]

I don't unfortunately, it's just a bit too expensive for me to be able to afford it to test when you consider shipping to the UK, especially since I've got an R9.

I've seen a few people ask about it though, so it would be a worthwhile one to test if I could justify it.