Block Blue Light: Bio Light 1800-4000K A21
Block Blue Light Bio Light 1800 to 4000K A21 light bulb test results
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The verdict
An adjustable LED A21 bulb. I measured 3 settings from 1834K to 4311K. Its color rendering runs from poor to excellent depending on the setting (CRI 58 to 97) and its body-clock signal runs low to high (15% to 75% of daylight).
Use the warm setting in the evening and the cool one by day: the body-clock signal changes 5 times between them. Colors only look right on the cooler setting.
CRI 58 to 97
CRI Re by setting: 58 at 1834K, 76 at 2177K, 97 at 4311K.
R9 -41 to 95
R9 by setting: -41 at 1834K, -1 at 2177K, 95 at 4311K. Saturated red: skin, wood, food.
1834K to 4311K
Sold as 1800 to 4000K. Gap from natural light 10 to 49%. Tint +0.0061, leans green.
15% to 75% of daylight
Melanopic DER by setting: 0.15 at 1834K, 0.32 at 2177K, 0.75 at 4311K. Low is easier on sleep at night; high helps you feel alert by day.
The settings
Pick a setting. Everything below follows it.
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.
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.
This bulbOther bulbsFaded: discontinued
Truer color, same color temperature
Still sold, within 300K of this bulb's best setting (4311K, CRI 97), with a higher CRI.
Norb Smile Soft 4000K A19CRI 98 · R9 93 · 4226KSimilar bulbs
Still sold, near the same color temperature, same E27 base where one qualifies.
Specs
Power, brightness and efficacy marked "rated" are the manufacturer's numbers. I have not measured them yet.
- Brand
- Block Blue Light
- Model
- Bio Light
- Type
- LED
- Shape
- A21
- Base
- E27
- Finish
- Frosted plastic
- Power (rated)
- 8W
- Brightness (rated)
- 700 lumens
- Efficacy (rated)
- 88 lumens per watt
- Dimmable
- No
- Sold as
- 1800 to 4000K
- Measured
- 1834 to 4311K (3 settings)
- Gap from natural light
- 10 to 49% (ASD)
- Tested
- Nov 18, 2024
- Instrument
- Handheld spectrometer (before the integrating sphere)
- Status
- Available