What does full visible spectrum reflectance mean and why does it matter?

ORCA Grow Film® is 94% reflective across the full visible spectrum. Which means it averages 94% reflectivity for every individual wavelength across the spectrum that is relevant for plant stimulation. See how ORCA Grow Film® performs against some well known materials in independent 3rd party testing. (More)

What we consider as visible light is actually a small portion of a continuous range of frequencies produced from the sun known as the electromagnetic spectrum. The subdividing of the entire spectrum into smaller spectra is done mostly on the basis of how each region of electromagnetic waves interacts with matter.

Human eyes are sensitive to only a very narrow band of wavelengths by which we see, we refer to it as the visible light spectrum. This visible light region consists of a spectrum of wavelengths which range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm.

Since each individual wavelength within this spectrum is “visible” to the human eye, the wavelengths are representative of a particular color.

People commonly use the acronym ROYGBIV for this narrow band of wavelengths to remember the order of color within the visible light spectrum, and its place in the overall electromagnetic spectrum. (Infrared spectrum (IR)/red wavelengths are to the right and violet wavelengths/ Ultraviolet (UV) spectrum are to the left.

The visible light spectrum is relevant to hydroponic gardening because it is roughly the same electromagnetic or “light” spectrum that is relevant to plant stimulation and growth. Simply speaking, a plant’s chlorophyll cells absorb light and in turn influence photosynthesis. Particular color bands or wavelengths (nm) found in the visible light spectrum can promote different cycles of plant growth; germination, growth, flowering, and budding.

Reflectance % Measurement, wavelength in the relevant spectrum:
The reflecting characteristics for any given material will be different for each electromagnetic wavelength. A measurement or reflective % for one wavelength is not a relevant indicator for an entire spectrum.

Example of relevant spectrum and measurement:
A material can claim to be 97% reflective, but what spectrum is it referencing - sound, heat, or light? Is it a single wavelength measurement, an average, a mean and in what range? It may sound good if a material claims to be 97% reflective, but if this value is measured at a single wavelength, say 216nm, it would mean the material is reflective in the ultraviolet spectrum, which would be detrimental for plant growth.

Why 94% reflectance matters:
Every time a light ray (radiant energy) contacts a surface, a portion of the energy is absorbed and a portion is reflected, but there is no energy loss. Materials that reflect significantly more radiant energy than they absorb are considered reflective. ORCA Grow Film® is 94% reflective across the full visible spectrum, or it only absorbs 6% of the radiant energy. Reflective materials are used to increase the overall effective coverage from the grow lights in a grow room. When you cover the walls, ceiling, and floors with a quality reflective material you can increase the overall efficiency of the grow room by 30 to 75 percent.

All grow room layouts and designs involve multiple reflections/light bounces due to corners, angles, and static objects in the grow room. A high performance reflector will minimize absorbance from multiple bounces and maximize the usable exiting light. A small difference in reflectance can make big difference for a grow room’s total lighting efficiency.