By Ra Optics
Your Screen.
After Dark.
The screen tint app that actually protects your circadian rhythm.
Your screen is destroying your sleep.
Blue light after sunset suppresses melatonin, disrupts your circadian rhythm, and causes eye strain, headaches, and poor sleep. Night Shift barely helps — it only goes to 2700K. Your biology needs deeper.
Poor Sleep
Blue light suppresses melatonin production by up to 50%
Eye Strain
Hours of bright screens cause headaches and digital fatigue
Disrupted Rhythm
Your body can't tell it's nighttime when your screen is daylight
Try it right now.
Same color science as the real app. Drag the sliders.
“Protect your light.” — Ra Optics
Drag the sliders — the photo tints in real time
Not all screen tints are equal.
Night Shift stops at 2700K — a mild warm orange. Sundown goes all the way to 500K. That's the difference between a nightlight and actual circadian protection.
Install
Download. Drag to Applications. Done. 398 KB.
Set your warmth
Slide from gentle amber to deep crimson. You choose how deep.
Forget about it
Auto-sunset mode activates at sunset, off at sunrise. Zero effort.
Engineered for your biology.
500K Deep Red
Goes deeper than any other app. Pure red for serious circadian protection. Night Shift stops at 2700K.
Glass UI Sliders
Warmth, intensity, and brightness — three separate controls. Gradient tracks with liquid glass thumbs.
Auto-Sunset
Activates at sunset, off at sunrise. Uses your location for precise timing. Set it and forget it.
Zero CPU
Uses macOS gamma tables — the same approach as Night Shift. No rendering loop. No battery drain.
Zero Tracking
No analytics. No databases. No phone-home. Your screen tint is your business.
Presets
Evening, Night, Sleep, Biohacker. One click. Plus custom scenes with golden hour, campfire, candlelight, and ember.
What people are saying.
“We have an audience of 100,000 perfectly aligned customers ready today. This will blow up across social media.”
Matt Maruca
Founder, Ra Optics
“It's already looking like it's gonna be much better than the other two. Much darker, deeper red. A lot simpler and easier to use.”
Jack R.
Co-founder, Sundown
“398 KB vs 83 MB. Zero tracking vs Google Analytics. This is what software should be — one thing done perfectly.”
Beta Tester
Biohacker
“I've been using Iris for years and always hated how glitchy it was. Sundown just works. Set it and forget it.”
Beta Tester
Software Engineer
Start protecting your eyes tonight.
7-day free trial. Cancel anytime.
The full picture.
Here's what you're actually installing.
| Night Shift | Flux | Iris | Sundown | |
|---|---|---|---|---|
| Blue Light Blocked | ~40% | ~85% | ~85% | 99.7% |
| Deepest Kelvin | 2700K | 1200K | 1200K | 500K |
| App Size | Built-in | 5 MB | 83 MB | 398 KB |
| CPU Usage | <1% | ~0.5% | 1-40% | 0.0% |
| Tracking | Apple | Minimal | Google Analytics | None |
| Bundled Databases | No | No | MySQL + PostgreSQL | No |
| Native ARM | Yes | Universal | x86 (Rosetta) | Yes |
| Price | Free | Free | $2/mo | $4.99/mo |
The Science of Light & Sleep
Get cutting-edge research on circadian rhythm, blue light, and screen health. Weekly insights from the frontier of light biology — free forever.
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Questions
How is Sundown different from Night Shift?+
Night Shift maxes out at 2700K — a mild warm orange that blocks about 40% of blue light. Sundown goes to 500K (pure red), blocking 99.7% of blue light. It's built for people who take circadian health seriously.
Does it really use 0% CPU?+
Yes. Sundown modifies your display's gamma tables — the same technique macOS uses for Night Shift. There's no rendering loop, no screen capture, no overlay window. The color shift happens at the display level.
Why is Iris 83 MB and Sundown is 398 KB?+
Iris bundles the entire Qt web framework, jQuery, MySQL client, PostgreSQL client, and Google Analytics. Sundown is pure Swift with zero dependencies. It does one thing and does it well.
Does Sundown track me?+
No. Zero analytics, zero telemetry, zero network calls. Your screen tint is your business. We don't even have a server to send data to.
Will this actually improve my sleep?+
Studies show that reducing blue light exposure 2-3 hours before bed can increase melatonin production by up to 58% and improve sleep quality significantly. Sundown goes deeper than any other software solution.
Can I get a refund?+
Yes. 30-day money-back guarantee, no questions asked.
Protect your eyes.
Starting tonight.
7-day free trial. 398 KB download. 30-second setup.
Start Free Trial — 7 Days Free