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On 02/11/2012 06:44 PM, Hellraiser wrote:
> I tada nas je Danijel Turina počastio još jednim biserom iz svoje
> nepregledne škrinje znanja:
>> imaju grozan
>> spektar,
> 
> one jeftinije imaju.

Sve imaju.

> skuplje osram i philips su mi oku ugodne. pretpostavljam da ti je jasan i
> pojam temperature boje, jer ako si kupovao samo one od 6000K, jasno da ti
> se nisu previše svidjele :)

Nećemo sad o kolorimetriji ali recimo samo da temperatura u Kelvinima
nije realistično mjerilo spektralne karakteristike bilo koje tehnologije
rasvjete osim žarne niti, zato što taj kriterij ne opisuje zastupljenost
pojedinih spektralnih komponenti u svjetlu, tako da većina rasvjetnih
tijela ima velike "rupe" i jako loše emuliraju sunčevu svjetlost koja
ima vrlo ravnomjernu spektralnu zastupljenost. U prijevodu, neonka od
5000K nije fazno pomaknuta volframska žarulja od 3000K, nego svjetlost
potpuno drugačije karakteristike koja bi u fotografskom smislu
zahtijevala ne fazni pomak, nego ulazni kalibracijski profil.

Više detalja:
http://en.wikipedia.org/wiki/Color_temperature#Spectral_power_distribution

"To the extent that a hot surface emits thermal radiation but is not an
ideal black-body radiator, the color temperature of the light is not the
actual temperature of the surface. An incandescent light bulb's light is
thermal radiation and the bulb approximates an ideal black-body
radiator, so its color temperature is essentially the temperature of the
filament.

Many other light sources, such as fluorescent lamps, emit light
primarily by processes other than thermal radiation. This means the
emitted radiation does not follow the form of a black-body spectrum.
These sources are assigned what is known as a correlated color
temperature (CCT). CCT is the color temperature of a black body radiator
which to human color perception most closely matches the light from the
lamp. Because such an approximation is not required for incandescent
light, the CCT for an incandescent light is simply its unadjusted
temperature, derived from the comparison to a black body radiator."

- -- 
http://www.danijel.org/
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