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Natural light color range (Color Temperature 1800-6500K)  


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Joined: 2 years ago
Posts: 11
01/01/2020 6:34 pm  

Natural light color range (Color Temperature 1800-6500K)

Daylight goes from a “warm” reddish-orange at dawn to bright white at high noon, and back to warm at dusk. With LEDs, you can adjust the natural color* by having either a “tunable” or self-adjusting light, which changes color as you dim it, between warm and white. Changing natural color has the enormous advantage of being more comfortable at different times or moods, and useful for different purposes. The current WindowLED is at a fixed level, and we should try developing adjustable options.

For comfort, a light too warm can be either relaxing like candlelight or gloomy depending on the time of day or your mood, and a cold light can be either brighten your day like a sunny day, or it can be harsh when you want to relax. For usefulness, it also has the great advantage of seeming much more dim when warm and much brighter when white, despite the same intensity and power (lumens). This is important when you’re wanting softer light when you’re watching a movie, or needing to focus and see more.

The halogen floor lamps and incandescent lights had this enormous advantage, which has gone unnoticed by most people as we moved to fluorescent lights, which are set at a single level, and LEDs, which are rarely adjustable, and both of which are almost always cold and white, to make up for them being too dim during the day, and require different bulbs for different times of day and purposes.

Because floor lamps use bulbs that are very low intensity, for years after the halogen lamps, people were stuck with diffuse lighting which used a 60w (500 lumen) bulb, and now that LEDs are around and have reached 3000 lumens, they have started to point upwards, but have to have are very white (3500-5000K) to compensate. Like the halogen lamps, with the WindowLED being so bright, you can have much warmer light. The current WindowLED is set at a warm level similar to the old incandescent lights (2700K), which is the best across its overall range (according to the current developers). If you’d like different LEDs with different natural color levels, you can make your own or have options you can swap out. With the replaceable LED assemblies, this will hopefully be somewhat easy. In developing a tunable or adjustable WindowLED, we can perhaps eliminate that necessity, and make it standard, or a separate option if it’s a lot more expensive.

Developing an adjustable warmth however has some difficulties that are fundamental. A major problem with changing natural color with an LED light is that it goes to being half as bright at it’s lowest and highest natural colors and brightest in the middle, as a bell curve rather than an upward curve. This is because an LED light with an adjustable warmth requires two sets of LEDs, one for the lowest end and one for the highest end. One goes dimmer as the color temperature is changed, and turns off at its lowest or highest end, and when both of them are at full brightness, it mixes the two. So, if an LED source were 10,000 lumens, it would only be 5,000 lumens at its warmest or whitest, and 10,000 in the middle. In order to have the ends be over 10,000 lumens, you would have to have a 20,000 lumen light.

Ideally you can have it at any natural color and brightness, but it may not be a huge deal for some people, or would be better than not having it adjustable at all. If we wanted to make it adjustable and also over a certain brightness across its range, we would have to program it to have a 20,000 lumen light and program it to max out at 10,000 lumens, and it would require an LED driver with twice the power.

An LED light with an adjustable color temperature also requires a different LED driver to power both sets of LEDs. This would require finding a driver that goes across the ideal range. Currently there is only one we have found that goes to 0.1%, but has a maximum of 60 watts, below 8,000 lumens, which would be 4,000 lumens at the extreme ends.

With a tunable LED, it would require two dimmers, again to power both LEDs. You’d also have to add this capability to the bluetooth program and app.
[NOTE: Forgot, could you just program it to be at any range, with one dimmer?

*This is called color temperature (CT), and can be made brighter or darker (lumens). It may seem counterintuitive that higher brightness is called “cold”. It is measured by how bright steel gets as it is heated, from cold to hot.