What is Full Spectrum Light?

You have heard people describe a particular light as full-spectrum and you have always asked the question, what is full-spectrum light? Not so many people can give a straight out answer to this question without having to explain first. We have broken this question to digestible nuggets to help you understand what a full spectrum light is.

Understanding Full Spectrum Light

Understanding how the full-spectrum light works have to start with understanding how the sun works, and the natural daylight feels. The essence of why plants grow isn't because of the compost you pour on them or the water, it isn't about the fertilizer too but the amount of light photosynthetic light they are exposed to. If you are growing outdoors, then you may not need a full spectrum light as the sun is sufficient to provide all the photosynthetic requirements that your plant needs.

Flowing from this, it then becomes apparent that full-spectrum light is designed to replicate the natural daylight and spectral distribution of the sun. In other words, it is the completeness of the spectral energy present in a light set that best replicates that of natural daylight. Since it tries to imitate natural light, full-spectrum lights are not only useful for planting or gardening alone. They are used in the art industry and for color matching, they are used in aquariums too. Although spectral energy is easily determined, whether it is full or not isn't something that is easily determined. One would have to use special spectrometric equipment to evaluate the nature of the spectrum in a light set to know whether it is a full spectrum light or note. 

Thankfully, there are standard full-spectrum lights designed and tested to be complete in this natural light replication.  So anytime you want to understand what a full spectrum light looks like, just imagine yourself seeing the natural sun rays or beams on a very sunny day.

How a Full-Spectrum Light Works?

Full-Spectrum Light

Let's pick it up from where we stopped. When you try to imagine the daylight, you will notice how evenly distributed the light energy is across an entire visible spectrum. You wouldn't see any spike, gap, or dips while under natural daylight. Now, compare with a daylight florescent and you will notice the light distribution then becomes different and unevenly distributed. This is to say that not every white daylight imitation lamps are full-spectrum lights.

Also, most full-spectrum lights are designed to have a higher color rendering index than your average fluorescent light or other types of lamps. They even appear brighter than the regular lamps when powered. This is because full-spectrum light uses phosphors to achieve a wider range of color temperatures, especially the Kelvin color temperature scale. There is nothing technical about the color temperature scale and color rendering index. It is just a way of determining how colors appear under a light source. Since the full-spectrum light is about replicating the natural light, it must be done perfectly. The natural daylight always has the CRI value of 100 and that means whenever you are looking at purchasing a full-spectrum light, it must equally have, at least, a CRI value of 95 and above. Anything lower than this CRI requirement will render colors poorly or inaccurately, and the difference between the natural daylight and the light source will render it quite unusual for which you need a full-spectrum light in the first instance.

Again, the color temperature scale is a way of measuring the warmness of the light. Your normal incandescent light source may have a color temperature rating ranging between 2500K to 3000K.  This produces a very yellowish and too warm color temperature which is different from the natural daylight and won't offer the same spectral distribution. The fluorescent also comes with a ranging color temperature between 2700K to 3500K and will not also offer any full-spectrum advantage because it has topo whitish-warm feeling. 

For a perfect full-spectrum source, it has to come with about 6500K color temperature rating with a perfect imitation of daylight that is often a balance between the yellow and warm-white color temperature. Together, the Color temperature rating and the color rendering index form the two major ways of measuring the fullness of a full-spectrum light source.

Advantages of the Full-Spectrum Light

Full-spectrum lights aren’t just for show or for imitating natural daylight only, they are important for all, but not limited to, all of the reasons below:

The Human Benefit

Aside from being awesome for gardening and planting, by stimulating a perfect PAR rate that the sun gives for the total benefits of plants, the full-spectrum light is also beneficial to humans. It reduces eyes strain that poor lighting may cause. Our eyes are quite sensitive and when colors are unnaturally portrayed, and we stare for too long, it may result in eyes fatigue or glare. Installing full-spectrum lights will help you retain that natural daylight color that your eyes are quite used to.

If adequately manufactured, under the right and CTR, full-spectrum light is capable of improving the human mood as well as mental health. Light is arguably a great determinate of mood, and that is why total darkness may throw people to sad or angry moods sometimes. Full-spectrum may improve Vitamin-D on our skin and this benefit may be as far-reaching as helping to improve dental health.

The Art Benefit

Art is all about colors and the greater you can improve colors; the more artistic an object becomes. Full-spectrum light helps in improving the color rendition of an object by making them as appealing as the natural daylight would have them be. The distribution of light from incandescent or fluorescent light sources may alter their natural color. For example, a glass of red wine may appear more pinkish under these light than normal.

A full-spectrum light helps in maintaining this color balance. It helps in illuminating true colors of objects, and also the true expression and details of things. That is why photographers, graphics designers, and general artists make full-spectrum lights their preference. Even the interior designers use full-spectrum light to bring the natural outdoor feel to the inside of a home.

Biological Productivity

Full-spectrum light helps to maintain the light balance needed to make organisms very active. The same way it helps to boost the growth and health of plants, grown without natural light, it helps other light-dependent animals such as fishes, especially those in aquariums, and even your pets. The same way light can change the mood of humans, it can change the productivity and activeness of animals and pets too.


As beneficial as full-spectrum light seems to be, it is the most difficult type of light to buy. This is because there are so many brands out there ready to portray their products as what they aren't. However, understanding what makes a full-spectrum light, as explained in this article, will help you ask the relevant questions when trying to purchase a full-spectrum light.

Incandescent light and fluorescent, no matter how well packaged and described, are not full-spectrum light.  What is full-spectrum light, being a question, is best answered by identifying a single distinguishing element which is, the ability to replicate the natural daylight.

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