It is very interesting sometimes when talking to our potential clients, just how fixated they become with the shape, size and finish of light fixtures. While this is an important factor for interior lighting with fixtures that are visible and compliment the décor of the house, it generally does carry the same importance when considering landscape lighting.
Landscape lighting is intended to make the landscape and external features of your architecture the star of the show, while the fixtures themselves remain less visible or out of sight altogether. The idea is to see the effects of the lighting and not the source of the light itself. This being the case, what becomes important is the quality and nature of the light itself.
Let's take a moment and review some of the terms and acronyms used to determine the quality of the light we are using.
In the days of halogen lamps, we would equate the "power" of a light source solely based upon the consumption of wattage for that particular lamp. The higher the wattage consumed by a filament, the brighter the lamp would be.
LEDs have revolutionized the way we measure the strength of light and we simply cannot rely on "wattage" consumption anymore because some LED sources are more efficient at translating energy to light than others. This is a term called efficacy and is a measure of how many LUMENS are being produced per watt of energy that is consumed. Therefore, it is particularly important to determine a LEDs usefulness for a specific task by understanding its measured LUMEN production.
Without getting overly technical, we measure light by 2 factors; Lux/cp (candle power) and Lumens. Lux/cp is a measurement of light levels at a particular distance from the source, whereas lumens are a measurement of the total amount of light output from the source itself (think of flashlights and brightness).
Most LED lamps today are measured in lumens but may also be accompanied by photometric data which includes Lux/cp data when used in a specific application or light fixture.
Color Rendering Index is a fractional measurement of the ability of the light to reflect or "render" the true color of the objects it is lighting.
For example, sunlight at noon has a CRI of 100% because most colored wavelengths of light are present in this bright, clean light. Because all the colored wavelengths are present in this light, the full spectrum of sunlight reflects back the true color of all objects that contain those spectral colors present in the light in a very true and accurate way.
In the same way, sunlight in the "golden hour" (about an hour before or after sunrise or sunset), the sunlight takes on a more red-golden tone. Blues and greens in the color spectrum of light are filtered out to a greater degree and reduced by the atmosphere, leaving more of the warm tones of the spectrum (reds, yellows, and oranges) to reflect back.
This is why photographers love this time of day because it makes their subjects look warm and inviting while filtering out more of the colder tones of blue and green.
Just as the sunlight contains all the colors of the spectrum, our LEDs do also, but much different varying degrees. Many LEDs are produced in varying degrees of true rendering ability.
Some LED sources will be high in the red and yellow spectrum but will suffer in the cool tones, leaving objects that contain these cooler tones looking bland and washed out.
LEDs with a higher CRI percentage produce a much more balanced and even spectrum of light and will render the true color of objects more accurately than light sources with a low rendering index.
Objects will look crisper and cleaner the higher the CRI index is.
There are many inexpensive LEDs on the market that are easy to acquire via the internet, but most will be using low-quality chipsets that have a very mediocre rendering percentage (usually less than 80%) and will be unflattering to the subjects that they are lighting.
A good CRI percentage for an LED will be anything 85% or greater. 90% or greater is a superb light source, but be prepared to spend more to get a quality product.
Correlated Color Temperature refers to the perceived "warmth" or "coolness" of the light itself. Most of us are very familiar with the light characteristics of incandescent and halogen light sources in our homes from years past.
These lamps were consistent and rendered light in the warm tone ranges of 2700° kelvin for standard incandescent lamps and up 3000° kelvin for halogen lamps. "Kelvin" is a measure a measurement of the color temperature of the light itself.
Cool tones such as daylight and moon light have cooler tones up to 9000° kelvin, whereas warmer tones of light such as candle light are down in the range of 1700-2200° kelvin.
The light color is very important when choosing how a person will interact with a particular environment or space. Cool white, or day light white light sources such as fluorescent lighting, are used in offices and commercial spaces to promote alertness and activity while warmer tones and sources are used in our living spaces to promote a calming and soothing effect that is warm and inviting.
Using quality light fixtures constructed of solid brass, copper, and stainless steel is incredibly important to ensure that your luminaires last a lifetime.
However, the key difference between a home and landscape that is simply "lit up" and one that looks truly exceptional, begins and ends with the quality of the light source itself. There is nothing more important than this.
At Lighthouse Outdoor Lighting®, we research, test and produce only the very highest quality LED light sources for use by our Lighthouse® team nationwide. Do not accept lower quality LED products offered by low-ball contractors and even some of the big-name lighting manufacturers in the marketplace today.
Lighthouse Outdoor Lighting® is a community of discriminating lighting designers who are passionate about providing the very best in product quality and lighting design to our discriminating clients across the country.