“The Perfect Light”
Quick Lighting Guide for Beginners

Artificial lighting is getting more and more important in our everyday life:
today we are aware that from the old halogen or incandescent lamps,
we have gained in terms of energetic efficiency,
however we have lost the quality of the light we were used to.

It is natural to expect that a lamp will make us perceive shapes and colours
exactly as we are used to see them in daylight.
No matter the time or the atmospheric conditions, the Sun light will always satisfy our expectations.
A good lighting, on top of granting the right level of light, has to make us perceive
the totality of natural colour, but also the tri-dimensionality of shapes and textures.

The arrival of LED brought a lot of enthusiasm and a lot of confusion amongst users,
mainly due to many parameters that we can select from (Watt, Lumen, Lux, Kelvin, CRI, …).

The fundamental data of a lighting source are featured by:

• Quality
• Tonality
• Quantity

Quality

When talking about light it’s normal to take sunlight as a reference.
The Sun, due to it’s nature, has a complete chromatic spectrum.

The spectrum of a light source determines the colours that will be perceived from our eyes.
A complete spectrum, like the solar one, grants the perception of around 10 million colours.

The more complete, the better the perception of reality in terms of colours, shades and vividness of the lit up surface.

Today the best parameter to value this characteristic is the Colour Render Index
The CRI value states how the light source spectrum is close to an ideal reference spectrum.

Tonality

The colour temperature is a parameter that measures the tone of light and allows to identify if it is cold, warm or neutral. 
During the day we perceive a variety of light tones, from the ethereal morning light to the white light of midday or the warm light at sunset.

The colour temperature of a light is measured in Kelvin (K).

Cold light lamps are luminous sources that appear white with a blue shade and are generally used to enhance cold colours:
for instance swimming pools, jewelleries, precious stones and metals, street lighting and car front lights.

Neutral light lamps are used to light working environments as offices and photographer sets.
This colour tone is also perfect in open-air sport locations such as stadiums and parks.

Warm light lamps are considered as the most comfortable ones, these lights are soft and enveloping.
They are usually associated to visual-comfort and indicated for residential, recreational and relax areas, restaurants.

Quantity

There are two measures that identify how much light a lamp generates:

– luminous flux 
– illuminance

The luminous flux of a lighting source is the quantity of light generated by a lamp and spread in the environment.
It is affected by its own design: materials, colours and engineering solutions.

The luminous flux is measured in Lumen (lm)

The illuminance is the quantity of light reaching a surface. 
It is determined by the luminous flux, the distance between the source and the surface
and the angle at which the light hits the surface. 

The illuminance is measured in Lux [lx]. 

Different norms indicate the optimal values for the type of context and use.