Talking about lighting by Leonardo

Leonardo

Elite Cafe Member
Joined
Jan 9, 2008
Messages
564
Location
Cordoba - Argentina
Thread starter #1
Hi everybody!

I will try to give you some technical tips about lighting from my best knowledge… and English language!

-At noon, in a sunny day, we have about 100,000 lux. This is a highest amount of natural light and the human eye is prepared to drive this level perfectly. So, no matter what quantity of lighting bulbs we have powered on, we cannot reach this level in a house or shop.

-The more difficult task requires more light. It is easy to find levels about 15,000 to 25,000 lux in an Operating Room in a Hospital.

-Indirect light eliminates the shadows. Also a frozen filter smooths the light bean providing a more comfortable illumination.

-The microscope optics lenses reduce the amount of light that effectively reaches the eyes. So, the more power optics would need even more lighting.

-For the engraving work, a level of lighting about 2,000 to 5,000 lux would be desirable.

-As a reference, a 36W fluorescent lamp setting about 1.5-1.7 meters over a table will give to us about 200 lux ON the table.

-The lighting level obtained on a surface is inversely proportional to the distance from the light source and this relation is quadratic; in other words, if we move the light source to the double distance we will have one quarter of the effective light on the surface. This is valid for the cameras flashes too.

-If we are working in a highly illuminated area, it is desirable to have a well-illuminated room too, to prevent being dazzled when changing from one point of view to another.

-Better color reproduction is obtained with warm lighting lamps.

-The highest human eye response (definition) is about 550nm (nano-meters), which is an orange-like color emitted by the sodium lamps but… the worst color reproduction is obtained in this wavelength.

Note: 1 FC (one candle by square foot) is about 10 lux. For example: 10 footcandles are about 100 lux.
When you are choosing a lamp or a lighting fixture, the power would be specified in lumens (!!!???). We have one lux when, on a one by one meter surface fall the light projected from one lumen source at one meter of distance; 1 lux is equal to 1 lumen per square meter (1 lm/m2). The difference between the lux and the lumen is that the lux takes into account the area over which the luminous flux is spread.

I have attached a guide scanned from a General Electric Lighting Estimator.

Hope this help! :) Leonardo.
 

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