Light is a complicated phenomena but there are some major characteristics that makes human eyes register and perceive different lights in different way.
First the color temperature - it is generally separated in cool and warm colors. Daylight color temperature is normally 5500-6500 K and is per definition a cool color and the eye interpret this as a blueish/white color.
The second important thing is the so called CRI - Color Rendering Index. This defines how well the colors in the illuminated object is reflected back to the eye and how accurate the color of the object is. This is measured in a scale up to 100 Ra. The closer to Ra 100 the more accurate to the daylight perception.
The third thing is the luminous flux (Lu) - the amount of light emitted by a light source. It is sometimes easy to use the wattage of the lights when comparing the power of the light but the more important thing is the luminous flux. The wattage is the input and the luminous flux is the output if you simplify it. The ratio Lm/W gives the indication of the efficiency for the light.
The metal halogen technology - HMI - gives a very good combination of the CRI, the color temperature and the lumen efficiency - superior many other light technologies.
- The color temperature for HMI is 6000 K and is like daylight.
- The CRI is higher than 90 in general which gives very clear contrasts and natural colors.
- The light efficiency between 80-90 lm/w reduce the need of input wattage.