Is it true that halogen lamps only produce warm light, whereas the new energy-saving fluorescent lamps and LED lights only produce cold light?
Incandescent light sources create light with greater emission in the red and yellow field, therefore a warm white light is perceived. Fluorescent and LED sources create light due to the conversion of blue and ultraviolet radiation. The first fluorescent lamps had a greater emission in the blue and green field, therefore a cold white light was perceived. Today, lamps are available in shades of white as required.
The UNI EN 12464 standard establishes 3 different classes:
warm white: < 3300K
neutral white: from 3300 to 5300K
cold white: > 5300K