Photometry and Colorimtry (Basic terms and Principles)

Following from my last blog, I completed a daylight research on 2 buildings: L’ hemisferic in Spain and the Kanazawa Umimirai Library in Japan. Findings are detailed in the images below

This slideshow requires JavaScript.

The topic above is very theory based however as lighting designers  it is imperative to know these as well.

First I must introduce you to the C.I.E Chromaticity Diagram. The best way I remember this is a colorful acrylic nail for the index finger. The C.I.E Chromaticity Diagram is the standard for primary colors developed in 1931. One must note that the CIE does not correspond to real colors as there are no real colors to be combined to give all possible colors. This relates back to my post in week 2 where I stated that whilst a standard is created on human perception each person has different levels of how Rods and Cones adjust to make out an object.

The second terminology is the Correlated Color Temperature (CCT) . This is measured in Kelvins and tells  how warm or cool white light appears. 1 Celsius = 273 Kelvin where 1000K is candle light (warm) 6000k is day light and 10000k is North light / blue sky

The color rendering index  (CRI)is a number which shows how well color comes out under light. It has nothing to do with CCT .

Luminous flux, measured in lumen is the total amount of light emitted by the light source

Luminous intensity measured in Candela is direction of the luminous flux

Illuminance is the amount of luminous flux falling on a given surface

Luminance measured in candela/meter squared indicates the perceived brightness of an illuminated or luminous surface

These terms are absolutely critical for any lighting designer to know. for the everyday person who for some reason seeks to remember these, here is a short story I put together to help myself remember these term… Enjoy!

‘I bought a bright red bag today. It was a very bright bag with an intensive luminous flux. It was so bright that the luminous intensity filled the entire room and illuminated at a 180 degree angle on the 4 black walls from the door way. Alas the luminous flux from the bright red bag produced a dull red luminance of the walls. I have never used that bag since!’


UTS Master of Design – lighting Studio


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: