The light color balance is measured by a Temperature Color Scale that uses Kelvin degree (Kº) as a reference to measure the different light wave lengths that configure the color spectrum of that particular light.
This is just a pattern since the wave length spectrum of a light bulb, for instance, is changing as the light is getting warmer so it creates a ‘discontinuous’ color light that our sight cannot appreciate. We only appreciate that is 'warm'.
Our sight automatically balances these irregular color distribution. Makeup foundations cannot do it. We all have experienced the base color not matching the skin, or a lipstick that seemed too harsh when we walked outside the makeup room... that is the reason!
We need to have the right light to pick the right color so that everyone looks naturally beautiful.
How we measure Light Color
Something similar occurs when a light source is not emitting an even color spectrum distribution but concentrations of one or few color like the fluorescent lights do. They emit higher concentrations of blue, green and even magenta, depending of the manufacturer and what it's called Color Rendering Index or CRI.
The CRI is a scale from 0 to 100 percent indicating how accurate a "given" light source is at rendering color when compared to a "reference" light source.
The higher the CRI the better. Light sources with a CRI of 85 to 90 are considered good at average color rendering. When it comes to tasks requiring the most accurate color discrimination like professional makeup for media, light sources with a higher CRI are needed.
These are the light color spectrum diagrams of different sources of light. They show a wide color range that is missing when compared to the daylight.
Incandescent and fluorescent bulbs have a CRI of 75-86 at its best, which means that part of the color spectrum is missing.
With a CRI of 96 The Makeup Light provides a full color spectrum light, almost like the natural daylight. This means that all the color information is already present in a full array like in the daylight. So you will be see colours as they really are in your makeup application.
It's important to note that CRI is independent of Color Temperature.
(Example: one 5000K "daylight" color temperature light source fluorescent might have CRI of 75 and The Makeup Light with the same color temperature has a CRI of 96).