#2 What Kelvin has to do with Melatonin!?

Aug 19, 2019




“I will love the light for it shows me the way, yet I will endure the darkness for it
shows me the stars.”
Og Mandino


Imagine life without light. We all would be lost in the black field. Everything would be here and now. No distance between us, no place to go, no time left. We would witness quantum filed, where al possibility exists and where there is no place, no time.

We would experience life differently. We would be just one thought away from everything that we imagined. But, it is still not time to write about the quantum filed. This time, I want to speak about the light, what is the role of the light in our daily living and what we should know about it to live life more joyously and according to the circadian rhythm.

When you are trying to determine what light will work for you, you need to find the optimum solution between the following measurement units: lumens, wattage, color temperature, and color rendering index. For each project, these performances need to be well designed. Also, to get the best outcome in your space, you need to choose carefully. Letʼs start with the Kelvins.


What is Kelvin?

Kelvin is a measurement unit for temperature. We are used to expressing the temperature in Celsius degrees. But, anyway, we are not talking about measuring the temperature of the room. We are talking about light.

Yes, let me easily explain.

Colour temperature is the color appearance of the lamp itself and the light it produces expressed on the Kelvin Scale. Kelvin is Celsius +273 (example: 20 Celsius Degrees = 293 Kelvins).

The color temperature of a light source is the temperature of an ideal blackbody radiator that radiates light of a color comparable to that of the light source.

You can imagine that you steadily heat a block of steel. You will see that at first, the steel glows orange, then yellow and so until it becomes white-hot. At any time during heating, we can measure the temperature of the metal in Kelvins and assign that value to the color being produced. This is the theoretical foundation behind color temperature.

Ever since Edison introduced us to the very first modern, prototypical, electric light bulb in 1879, we are used to that everything is illuminated by incandescent bulbs with their warm white color temperature (2700 K). This has resulted that for the last 130 years, everything around us with a slightly yellowish glow, especially in our homes, making the colors around us feel warm and cozy.

There are three primary types of color temperature for light bulbs:

    1. Warm White (Soft White) 2700 K – 3000 K
    2. Cool White (Bright White) 3500 – 4100 K
    3. Daylight 5000 K – 6500 K


Source: https://www.lightingdesignlab.com/resources/articles/articles-lightingfundamentals/color-temperature


More lumens = more light

Well, I would also like to introduce you to the lumen. It is one of the essentialparameters while doing light calculation process for the project.

Lumens are the amount of the visible light a source can produce. More lumens the light bulb has, the more brightness there is. This is not the case with watts.
This does not mean that watts are bad, but they measure energy use, not light output. With the energy-efficient LED technology, we do not have to rely any more upon wattage to indicate how bright a bulb is.

Wattage is the amount of the watts or units of power the light requires.

Colour Rendering Index (CRI) is a measure of quality and help to reveal light sources ability to show colors as they indeed are. The higher CRI is, it will produce a better quality of light. CRI is different than color temperature because instead of determining what color light will provide, the CRI will evaluate how well colors will look under that light.


Source: http://www.westinghouselighting.com/lighting-education/colorrendering-index-cri.aspx


Recommendation for illumination

The higher the degrees Kelvin is, the whiter the color temperature. It is also important to understand that the whiter lights will appear brighter than those of a lower Kelvin degree, but the amount of the lumens (amount of light, I will explain more in details further) does not change, so the true brightness of the object is not affected.

Although many feel cool white lights are brighter than warm white lights, it is more a perception than a reality. Cool white has a higher wavelength frequency and therefore is more intense to our eyes, making it appear brighter. However, If you compare a warm and cool white light that delivers the same amount of lumens, they will both be as bright as the other, but produce different colors.

Even though our eyes have adjusted to the soft white color temperature of incandescent bulbs over the years, it is not correct to state that this is the best option for all lighting applications. Here are some recommendation also taking into account altering the contrast throughout the space.

  1. Less than 2000 K glow of light, similar to candlelight, the best option for low-light areas where ambient illumination is welcomed.
  2. Warm white (2000 K – 3000 K) is the best option for bedrooms, living rooms, dining rooms, and outdoor spaces because in those spaces we want
    to have traditional warm colors and to feel cozy.
  3. Cool white (3100 K – 4500 K) is best in kitchens, bathrooms, offices, workspaces and vanities where task lighting is needed since we want more
    whiter and energetic feeling.
  4. 4600 K – 6500 K gives off a bright amount of blue white light, similar to daylight. This is the best option for display areas and work environments
    where very bright illumination is needed.
  5. 6500 K and more is the best for the places for reading, intricate project, concentration, applying the makeup since it provides the greatest contrast
    among colors. It is usually found in commercial locations.

In general, if you need to be more productive, it is better to choose cool white, which has a higher frequency and it is more intense to our eyes. On the other hand, warm white carries a lower frequency than cool whites and therefore are less intense to our eyes, so for our eyes, it is more relaxing mood to be around warm white light (as well as in my case).


Source: https://blog.birddogdistributing.com/color-temperature-originapplication/


What is Melatonin?

The circadian rhythm is a natural, internal process that regulates the sleepwake cycle and repeats roughly every 24 hours. At 9 p.m. humans body starts preparing to get rest. This means that the body adapts to produce the melatonin. The pineal gland is a small endocrine gland, found in the vertebrate brain, which is a part of your endocrine system, producing the hormone melatonin.

Melatonin helps to control our wake and sleep cycles. During the day melatonin production is lowered, but once the sun goes down, its rises and tired feelings start to appear. Production of melatonin helps keep our mind sharp, and it is produced in the night and decreases in the day. Sleeping in complete darkness helps our body produce more natural melatonin. This hormone induces rest and also anticancer properties.



How does the light affect your sleep and health?

Although it is environmentally friendly, blue light can affect our sleep and potentially cause disease. Until the advent of artificial lighting, the sun was a significant source of lighting, and people spent their evening in relative darkness. Now, in the world, evening are illuminated, and we take our easy access to all those lumens pretty much for granted. At night, light throws the bodyʼs biological clock – the circadian rhythm, out of the balance, so this means that sleep suffers.

Not all colors of light have the same effect. Blue wavelengths are beneficial during the daylight hours because they boost attention, reaction time, and mood, but on the other hand, they seem to be the most disruptive at night

With the proliferation of electronics with screens, as well as energy-efficient lighting, we are increasingly exposed to blue wavelengths, especially after sundown.

In order to protect yourself from blue light at night, it is an excellent choice to use warm white color temperate light in bedrooms. Before going to sleep two to three hours, avoid looking at bright screens. So, if you have to use your phone, you can turn on the night shift option to eliminate blue light. If you watch TV, you can use glasses to reduce the blue light, also during the working period. But, I would suggest you read a book or listen to music — additionally, no stress from the bad news on TV in order to be more calmer.

Hope that you will test advice and I hope that you will benefit from it!


Source: https://www.health.harvard.edu/staying-healthy/blue-light-has-a-darkside


“To shine your brightest light is to be who you truly are.”
Roy T. Bennett


Petra Mesarić, PhD 

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