Yuji: WELL24 Day 4000K A19

4117KCool whiteDiscontinued
LEDA19E2611WPlasticDimmable

Yuji WELL24 Day 4000K A19 light bulb test results

The verdict

A 4117K LED A19 bulb, now discontinued. Its color rendering is fair (CRI 85, R9 75) and its body-clock signal is very high (83% of daylight).

A strong daytime light. Too stimulating for the last hours before bed. It is no longer sold.

Tested Jun 17, 2023 · handheld spectrometer · how I test

How true do colors look?Fair

CRI 85 · Rf 81

CRI Re, the average of all 15 samples (Ra 87). #63 of 84 white-light bulbs.

4060809095100
How do reds look?Good

R9 75

Saturated red: skin, wood, food. 100 is perfect. #50 of 86 white-light bulbs.

-6005090100
What color is the light?Cool white

4117K

Sold as 4000K. Gap from natural light 18% (moderate). Tint +0.0042, close to neutral.

1000K1800K candle2700K4000K6500K
How strong is its body-clock signal?Very high

83% of daylight

Melanopic DER 0.83. Low is easier on sleep at night; high helps you feel alert by day.

00.2 candle0.5 incandescent1.0 daylight

The light

Measured spectrum, 380 to 780 nm, scaled to its peak.

Spectrum
Light color4117K
RosyNeutralGreen
Gap from natural light18%Moderate. Average spectral difference (ASD) from natural light at 4117K, 425 to 690 nm. 0% is natural light. The yellow line on the spectrum.
Melanopic DER0.83Body-clock stimulus per lumen. Daylight is 1.0, a candle about 0.2.

How colors look

The red line pulls out where colors get more vivid and pinches in where they dull. Hover a bin for its numbers.

Color Shift Map
TM-30 Rf81
TM-30 Rg91Slightly dulls colors (100 is neutral)
CRI Re85
CRI Ra87
Not measured

Where it ranks

Every white-light bulb I have tested, in its own light color. Left is warmer, up renders color more truly. Tap a dot to open that bulb.

Shaded: CRI 90 and up1500K2000K2700K3500K5000K7000K5060708090100Measured color temperature (log scale). Left is warmer.CRI ReBlock Blue Light Bio Light 1800 to 4000K A21: 4311K, CRI 97GE Halogen 2700K A19: 2780K, CRI 99GE Halogen 2800K A19 29W: 2870K, CRI 98GE Halogen 2800K A19 53W: 2956K, CRI 99GE Halogen 2850K A19: 2911K, CRI 99GE Incandescent 2850K A21 150W: 2907K, CRI 99GE Incandescent 2850K A21 200W: 2927K, CRI 98GE Sun Filled 2700K A21: 2794K, CRI 96GE Sun Filled 2700K BR30: 2748K, CRI 96GE Sun Filled 5000K A21: 5136K, CRI 98GE Sun Filled 5000K BR30: 5332K, CRI 98GE Vintage 2000K A15: 2050K, CRI 80GE Vintage 2000K ST19: 2080K, CRI 80GE Vintage 2150K A15: 2231K, CRI 81GE Vintage 2150K A19: 2135K, CRI 78GE Vintage 2200K G25 4.5W: 2131K, CRI 78GE Vintage 2200K G25 5.5W: 2212K, CRI 80GE Vintage 2200K ST19: 2240K, CRI 81Harth Nite Nite 1600K A15: 1658K, CRI 58Harth Nite Nite 1900K C35: 1947K, CRI 61Harth Sleep Shift 1600K A19: 1600K, CRI 58Kinur Sleep 1800K A15: 1912K, CRI 49Kinur Sleep 1800K A19: 1905K, CRI 49Koze Day 5000K A19: 4976K, CRI 96Koze Sleep 1600K A15: 1590K, CRI 57Lighting Science Sleepy Baby 2100K A15: 2063K, CRI 77Low Blue Lights Sleep Light Bulb 2200K A19: 2200K, CRI 53Norb Everyday-Sun 5000K A19: 4928K, CRI 90Norb Everyday-Sun Soft 4000K A19: 4033K, CRI 92Norb Sleep CA 2650K A19: 2708K, CRI 96Norb Smart 2650 to 5000K A19: 5201K, CRI 97Norb Smile 5000K A19: 5257K, CRI 98Norb Smile Soft 4000K A19: 4226K, CRI 98Philips Ultra Definition 2700K A15: 2853K, CRI 96Philips Ultra Definition 2700K A19 5W: 2818K, CRI 95Philips Ultra Definition 2700K A19 8W Clear Glass: 2841K, CRI 96Philips Ultra Definition 2700K A19 8W Frosted Glass: 2775K, CRI 96Philips Ultra Definition 2700K A21 11W: 2719K, CRI 95Philips Ultra Definition 2700K A21 13.5W: 2659K, CRI 95Philips Ultra Definition 2700K BA11: 2777K, CRI 96Philips Ultra Definition 2700K BR30: 2747K, CRI 93Philips Ultra Definition 2700K G25: 2818K, CRI 96Philips Ultra Definition 2700K R20: 2730K, CRI 90Philips Ultra Definition 5000K A15: 5238K, CRI 96Philips Ultra Definition 5000K A19 5W: 5281K, CRI 96Philips Ultra Definition 5000K A19 8W Clear Glass: 5296K, CRI 95Philips Ultra Definition 5000K A19 8W Frosted Glass: 4871K, CRI 95Philips Ultra Definition 5000K A21 11W: 5335K, CRI 96Philips Ultra Definition 5000K A21 13.5W Clear Glass: 5242K, CRI 95Philips Ultra Definition 5000K A21 13.5W Frosted Glass: 4961K, CRI 93Philips Ultra Definition 5000K BR30: 5246K, CRI 96Philips Ultra Definition 5000K G25 5W Clear Glass: 5198K, CRI 96Philips Ultra Definition 5000K G25 5W Frosted Glass: 5160K, CRI 94Philips Vintage 2000K A15: 2048K, CRI 77Philips Vintage 2000K A19: 2017K, CRI 77Philips Vintage 2000K B11: 2034K, CRI 78Sunlite Incandescent 2600K A15: 2666K, CRI 98Sunlite Incandescent 2850K C7: 2344K, CRI 98Sylvania Natural 2700K A19 11W: 2699K, CRI 91Sylvania Natural 2700K A19 8W: 2760K, CRI 91Sylvania Natural 2700K A21: 2746K, CRI 90Sylvania Natural 2700K BR30: 2796K, CRI 92Sylvania Natural 2700K BR40: 2771K, CRI 91Sylvania Natural 3500K A19: 3536K, CRI 89Sylvania Natural 3500K A21: 3418K, CRI 90Sylvania Natural 5000K A19 11W: 4893K, CRI 89Sylvania Natural 5000K A19 8W: 5462K, CRI 91Sylvania Natural 5000K A21: 5248K, CRI 87Sylvania Natural 5000K BR30: 5508K, CRI 90Sylvania Natural 5000K BR40: 5369K, CRI 89Waveform Candelabra 2400K CA11: 2500K, CRI 96Waveform Centric Daylight 5000K A21: 5085K, CRI 96Waveform D50 5000K A19: 5135K, CRI 96Waveform FilmGrade 5600K A19: 5804K, CRI 93Waveform Lux24 2400K A19: 2457K, CRI 91Waveform Superwarm 1700K A19: 1705K, CRI 80Yuji CRI-MAX 5000K A19: 5091K, CRI 93Yuji CRI-MAX 5600K A19: 5740K, CRI 92Yuji NormLite 5000K A19: 5254K, CRI 97Yuji SunWave 3000K A19: 3074K, CRI 98Yuji SunWave 4000K A19: 4115K, CRI 97Yuji SunWave 6500K A19: 6623K, CRI 95Yuji WELL24 Nite 2200K A19: 2213K, CRI 82This bulb

This bulbOther bulbsFaded: discontinued

Truer color, same color temperature

Still sold, within 300K of this bulb, with a higher CRI.

Norb Smile Soft 4000K A19CRI 98 · R9 93 · 4226KBlock Blue Light Bio Light 1800 to 4000K A21CRI 97 · R9 -41 · 4311KYuji SunWave 4000K A19CRI 97 · R9 98 · 4115KNorb Everyday-Sun Soft 4000K A19CRI 92 · R9 98 · 4033K

Similar bulbs

Still sold, near the same color temperature, same E26 base where one qualifies.

Truer colorNorb Smile Soft 4000K A194226K · CRI 98 · R9 93 · 74% melanopicBetter redsNorb Everyday-Sun Soft 4000K A194033K · CRI 92 · R9 98 · 73% melanopicStronger daytime lightYuji SunWave 6500K A196623K · CRI 95 · R9 92 · 104% melanopic

Specs

Power, brightness and efficacy marked "rated" are the manufacturer's numbers. I have not measured them yet.

Brand
Yuji
Model
WELL24 Day
Type
LED
Shape
A19
Base
E26
Finish
Plastic
Power (rated)
11W
Brightness (rated)
1,100 lumens
Efficacy (rated)
100 lumens per watt
Dimmable
Yes
Sold as
4000K
Measured
4117K
Gap from natural light
18% (ASD)
Tested
Jun 17, 2023
Instrument
Handheld spectrometer (before the integrating sphere)
Status
Discontinued