Well our SUN is in the 5000 - 6000k range with up to 6700k considered sunlight.
10k is very white with the blues starting in at 14k and 20k considered blue.
Actinic is in te 50k range (near violet/ ultra violet).
But that's only part of the story. You also have to consider the full spectrum output of a bulb, not just it's peak output. That is measured in nano meters (03 Actinic is 420 nm)...
Light Spectrum in NM
Violet Light
The visible violet light has a wavelength of about 400 nm. Within the visible wavelength spectrum, violet and blue wavelengths are scattered more efficiently than other wavelengths. The sky looks blue, not violet, because our eyes are more sensitive to blue light (the sun also emits more energy as blue light than as violet).
Indigo Light
The visible indigo light has a wavelength of about 445 nm.
Blue Light
The visible blue light has a wavelength of about 475 nm. Because the blue wavelengths are shorter in the visible spectrum, they are scattered more efficiently by the molecules in the atmosphere. This causes the sky to appear blue.
Green Light
The visible green light has a wavelength of about 510 nm. Grass, for example, appears green because all of the colors in the visible part of the spectrum are absorbed into the leaves of the grass except green. Green is reflected, therefore grass appears green.
Yellow Light
The visible yellow light has a wavelength of about 570 nm. Low-pressure sodium lamps, like those used in some parking lots, emit a yellow (wavelength 589 nm) light.
Orange Light
The visible orange light has a wavelength of about 590 nm.
Red Light
The visible red light has a wavelength of about 650 nm. At sunrise and sunset, red or orange colors are present because the wavelengths associated with these colors are less efficiently scattered by the atmosphere than the shorter wavelength colors (e.g., blue and purple). A large amount of blue and violet light has been removed as a result of scattering and the longwave colors, such as red and orange, are more readily seen.
Color Wavelength (nm) Frequency (THz)
Red 780 - 622 384 - 482
Orange 622 - 597 482 - 503
Yellow 597 - 577 503 - 520
Green 577 - 492 520 - 610
Blue 492 - 455 610 - 659
Violet 455 - 390 659 - 769
OK so now we have Temperature ratings and spectrum output.
What does it all mean. You may need to read this next aprt a couple of times. It's an excerpt from an article by Andrew Treveo-Jones:
"Yet another factor to consider is that different brands of lamps will have different output spectra and light output even if they are the same wattage and claimed colour temperature. You may even see differences between lamps of the same brand and same claimed colour temperature. Also,the claimed colour temperatures of lamps is only very approximate and gas discharge lamps don't really simulate theoretical black bodies.
Assuming that you are measuring each lamp under the same conditions and the sensor is not under reading blue light, you should still expect to see less PAR with lamps of the same wattage but with a higher colour temperature because there will be proportionally more photons with higher energy levels. As energy can not be created nor destroyed, the same amount of input energy (the wattage of the lamp) cannot produce more energy and so there will be fewer total photons produced by a lamp that has more blue light."
Clear as mud?
