The science
At night, you need to reduce your blue light exposure.
Abendrot targets the root cause of sleep disruption by minimizing the specific short-wavelength, melanopic light (blue/cyan) that tricks your body clock into thinking it's still daytime.[1,4-6]
Your body's internal clock processes light differently than your eyes do.1 The real goal is to reduce your exposure to sleep-disrupting blue and cyan light (short-wavelength, melanopic light) in the evening, aligning with your natural circadian rhythm.[4-6]
1 Your clock reads blue differently than your eyes do.
Rods and cones make the picture. A separate melanopsin system helps tell the brain whether it is day or night, and it is most sensitive around blue-cyan light near 480–490 nm.12 That is the band screen warming is meant to attenuate first.4
2 Warmth is a spectral edit, not a sleep claim.
Lowering Kelvin is useful only because it changes the spectrum: less energy in the short wavelengths the melanopic system weights heavily.4 Abendrot’s everyday warm range is built around that input-side change: remove blue first, then leave the rest of the evening tradeoff to your eyes and the slider.
3 Melanopic load is the better evening word than brightness.
In a controlled display study, the melanopic content of evening screen light mattered even when ordinary brightness and color appearance were separated from it.5 That is why Abendrot talks about blue-rich light, not just whether the screen looks bright or beige.
4 Dim still matters.
Warming changes color. Dose still depends on intensity. Expert consensus frames evening light in melanopic EDI at the eye, and nocturnal light response rises steeply with brightness.68 The honest habit is warm and dim, not warm and glaring.
5 There is no perfect setting for everyone.
People vary by more than fifty-fold in sensitivity to evening light, so a single universal number would be fake precision.7 Abendrot gives you an adjustable evening nudge, not a clinical tool or an outcome guarantee.
How it compares
Distinctly better than Night Shift and f.lux
Night Shift is the easy option built into macOS; f.lux is the powerful veteran that goes deeply warm. Abendrot reaches further than both - and stays out of your way while doing it.
Warmest setting
~2700–3400 K1 - never reaches candlelight
Down to ~1200 K at its warmest ember3
Down to 500 K in Cozy mode4 - deeper than f.lux, near pure candlelight
Blue at the warmest setting
Reduced, but not eliminated2
Heavily reduced at its warm settings
Driven to zero by 1900 K4
External & multiple displays
Apple’s own displays; inconsistent on third-party monitors1
Every display, via software gamma
Warms external monitors at the hardware level (DDC), with gamma + overlay fallback - and re-applies when you plug or unplug a screen
Background memory use
Built into macOS - no separate app process
Runs as a separate background app
Small menu-bar helper with no per-frame overlay
Fullscreen apps & video
Stays applied
Can stop applying after a fullscreen app until relaunched5
Stays applied at the system color level - no quit-and-relaunch
Open & private
Closed-source; Apple’s telemetry
Closed-source
Open source (MIT), zero telemetry by default