CRI measures how accurately a light source renders colors compared to natural daylight (CRI 100). Always choose CRI 90+ for living areas, kitchens, and bathrooms — it’s independent of color temperature.
Food & Produce
CRI 90+ makes reds vibrant and meat look fresh. CRI 80 makes tomatoes appear dull and brownish.
Wood & Finishes
Low CRI flattens grain and makes oak look orange. CRI 90+ reveals natural texture and depth.
Skin Tones
High CRI prevents the greenish or washed-out cast common in offices with fluorescent lighting.
Circadian Lighting Guide
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Dawn
Morning
Midday
Afternoon
Evening
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6 am8 am10 am12 pm3 pm6 pm9 pm
Morning (6–10 am)Use 5000–6500K to boost alertness and suppress melatonin. Great for kitchens and home offices.
Midday (10 am–3 pm)4000–5000K maintains energy and focus. Ideal for task areas and offices.
Afternoon (3–6 pm)Transition to 3000–3500K to begin winding down. Dining and living areas benefit here.
Evening (6–10 pm)Drop to 2700K or lower. Avoid blue-rich light — it delays sleep onset by up to 90 minutes.
Night (10 pm+)Use 1800–2200K amber only. Dim lights to 10–30%. Avoid ceiling lights; use floor and table lamps.
Dim-to-Warm Technology
🕯 What is Dim-to-Warm?
Standard LED bulbs maintain their color temperature when dimmed (e.g. a 3000K bulb stays 3000K at 10%). Dim-to-Warm LEDs mimic incandescent behavior — as you dim, the light automatically shifts warmer.
1800K (dim)2200K2700K3000K (bright)
Look for bulbs labeled “Dim to Warm”, “Candle Dim”, or CCT range like 1800K–3000K. They cost more but produce the most natural, relaxing ambience in dining rooms, bedrooms, and lounge spaces.
Application Warnings
⚠️ 6500K in Bedrooms
Daylight-spectrum light at night significantly suppresses melatonin. Avoid in any room used in the evening. Even brief exposure (20–30 min) before bed can delay sleep.
⚠️ 1800–2200K for Task Work
Candlelight temperatures are too dim and warm for reading, cooking prep, or detail work. Reserve for ambience and mood lighting only.
ℹ️ CCT vs Brightness
Color temperature and brightness are separate. A 2700K bulb can be very bright (1200+ lumens). Don’t confuse warm color with dim output — choose both independently.
ℹ️ Mixed CCT in One Room
Mixing 2700K and 4000K fixtures in the same room creates a jarring, incoherent feel. Stick to one temperature per space, or use tunable white fixtures.
✅ Tunable White Solution
Smart tunable white bulbs (e.g. Philips Hue White Ambiance, LIFX) let you change CCT throughout the day from one fixture. The best of all worlds.
✅ Layer Your Lighting
Combine ambient (overhead, 3000K), task (under-cabinet, 4000K), and accent (warm 2200K) in the same kitchen. Different layers, different CCTs — intentionally chosen.
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The calculators and tools on LightingCalc.lighting are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. LightingCalc.lighting makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.
