know before buying LED Bulbs ( LESSON :2)
(3) Correlated Color temperature (CCT):
- Color temperature refers to the light’s color characteristics.
- Color Temperature is measured in Kelvin.
- It refer to the warmness or coolness of the light that bulb produces.
- The color temperature of a light source is a numerical measurement of its color appearance.
- This temperature is based on the principle that any object will emit light if it is heated to a high enough temperature and that the color of that light will shift in a predictable manner as the temperature is increased.
- Color temperature is a description of the warmth or coolness of a light source. When a piece of metal is heated (temperature increases) the color of light it emits will change. This color begins as red in appearance and graduates to orange, yellow, white, and then blue-white to deeper colors of blue.
- Color Temperature is not an indicator of lamp heat.
- The sun, for example, rises in morning at approximately 1800 Kelvin and changes from red to orange to yellow and to white as it rises to over 5000 Kelvin at high noon. It then goes back down the scale as it sets in evening.
- The warm white ranges from about 2700k to 3800k, natural white ranges from 3800k to 4800k, pure white or daylight from about 4800k to 6000k. Cool white starts from around 6000k upwards.
- Colors and light sources from the red/orange/yellow side of the spectrum are described as warm (incandescent) and those toward the blue end are referred to as cool (natural daylight).
- In Color Temperature Value higher Kelvin temperatures (3600–5500 K) are consider cool and lower color temperatures (2700–3000 K) are considered warm.
- When choosing a color, the two considerations are important one is color rendering (How well the light shows the true color of objects) and temperature.
(1) Soft White / Warm White (2700K- 3000K):
- Warm light is preferred for living spaces because it is more flattering to skin tones and clothing.
- Recommended for indoor general and task lighting applications.
- Living rooms
- Bed rooms
- Rooms decorated in earthy tones (reds, oranges, and yellows)
- It gives effect like incident or halogen Light.
(2) Natural / Cool White (3500K- 4500K):
- Cool light is preferred for visual tasks because it produces higher contrast than warm light.
- Recommended for use in Domestic Applications.
- Warmer Whites are preferable in living and dining areas as well as reception areas to create a more relaxed environment.
- Natural Whites are preferable for kitchens and bathrooms where tasks are performed.
- Suitable for work areas where contrast is important.
- Kitchen
- Bath rooms
- Rooms decorated in airy, fresh hues (blues, greens, whites)
- It gives effect like Fluorescent Light.
(3) Bright White (4500-5000K):
- Recommended for use in:
- Office
- Study Room
(4) Daylight / Full Spectrum (5000K- 6500K):
- Recommended for use in:
- Garage
- Office
- Industrial and hospital areas.
| Lighting Source CCT | |
| Source | Color temperature in Kelvin |
| Skylight (blue sky) | 12,000 – 20,000 |
| Average summer shade | 8000 |
| Light summer shade | 7100 |
| Typical summer light (sun + sky) | 6500 |
| Daylight fluorescent | 6300 |
| Xenon short-arc | 6400 |
| Overcast sky | 6000 |
| Clear mercury lamp | 5900 |
| Sunlight (noon, summer, mid-latitudes) | 5400 |
| Design white fluorescent | 5200 |
| Special fluorescents used for color evaluation | 5000 |
| Daylight photoflood | 4800 – 5000 |
| Sunlight (early morning and late afternoon) | 4300 |
| Brite White Deluxe Mercury lamp | 4000 |
| Sunlight (1 hour after dawn) | 3500 |
| Cool white fluorescent | 3400 |
| Photoflood | 3400 |
| Professional tungsten photographic lights | 3200 |
| 100-watt tungsten halogen | 3000 |
| Deluxe Warm White fluorescent | 2950 |
| 100-watt incandescent | 2870 |
| 40-watt incandescent | 2500 |
| High-pressure sodium light | 2100 |
| Sunlight (sunrise or sunset) | 2000 |
| Candle flame | 1850 – 1900 |
| Match flame | 1700 |
| Skylight (blue sky) | 12,000 – 20,000 |
| Average summer shade | 8000 |
| Light summer shade | 7100 |
| Typical summer light (sun + sky) | 6500 |
| Daylight fluorescent | 6300 |
| Xenon short-arc | 6400 |
| Overcast sky | 6000 |
| Clear mercury lamp | 5900 |
| Sunlight (noon, summer, mid-latitudes) | 5400 |
| Design white fluorescent | 5200 |
| Special fluorescents used for color evaluation | 5000 |
| Daylight photoflood | 4800 – 5000 |
| Sunlight (early morning and late afternoon) | 4300 |
| Bright White Deluxe Mercury lamp | 4000 |
| Sunlight (1 hour after dawn) | 3500 |
| Cool white fluorescent | 3400 |
| Photoflood | 3400 |
| Professional tungsten photographic lights | 3200 |
| 100-watt tungsten halogen | 3000 |
| Deluxe Warm White fluorescent | 2950 |
| 100-watt incandescent | 2870 |
| 40-watt incandescent | 2500 |
| High-pressure sodium light | 2100 |
| Sunlight (sunrise or sunset) | 2000 |
| Candle flame | 1850 – 1900 |
| Match flame | 1700 |
CCT – Correlated Color Temperature
| |||
| Kelvin | Associated Effects | Type of Bulbs | Appropriate Applications |
| 2700° | Warm White, Very Warm White | incandescent bulbs | Homes, Libraries, Restaurants |
| 3000° | Warm White | most halogen lamps, Slightly ‘whiter’ than ordinary incandescent lamps | Homes, Hotel rooms and Lobbies, Restaurants, retail Stores |
| 3500° | White | Fluorescent or CFL | Executive offices, public reception areas, supermarkets |
| 4100° | Cool White | Office, classrooms, mass merchandisers, showrooms | |
| 5000° | Daylight | Fluorescent or CFL | Graphic industry, hospitals |
| 6500° | Cool Daylight | Extremely ‘white’ | Jewelry stores, beauty salons, galleries, museums, printing |