Lighting Color

[Moisted]

This may have been discussed before, please forgive the redundancy, but I'm getting confused lately about how to determine the color of a bulb.

Is the color temperature (in degrees kelvin) a good measure of what color light you're gonna get from the bulb, or does that also depend on different peeks in the spectrum?

In other words, is a 6500K bulb always bluer than a 5300K, or does it also depend on other stuff (like peeks in color spectrum, etc.)? I've been getting different responses from different sources.

Thanks in advance.

[m.lemay]

or does it also depend on other stuff (like peeks in color spectrum, etc.)?

Color temp. is not an accurate way to select bulbs for a planted tank. You want bulbs with peaks in the blue and red spectrum. Check out the post at the top of the lighting section titled "Lumens and PAR" for more specific info.


Marcel

[Moisted]

Thanks Marcel. I appreciate that plants need light that peeks in red and blue regions. But I wanted to know how we can determine the color of a bulb (regardless of the intensity or appropriateness).

Tell you why I'm asking. I needed to replace my florescent bulb, and was deciding between a 6500K and a 5300K. The spectra distribution of both lamps seemed pretty close. I went with the 6500K because I thought it'd be bluer, I like a little hint of blue. But it's actually pretty yellow...

The guy at LFS tells me the 5300K is bluer than the 6500K. But that doesn't make sense to me.
Thanks

[m.lemay]

I'm sorry, I misread the question.
Generally speaking , the red tones refer to lower kelvin #s, blue tones refer to high kelvin #s.
Kelvin temp ratings refer more to how the light looks rather than spectral peaks.

Marcel

[GulfCoastAquarian]

The Kelvin rating is merely an indicator of the color that the bulb will appear to our eyes. The popular Perfecto strip with 9325K Power Compact bulbs is more red/violet to the eye than most 6500K Power Compact bulbs.

As a rule of thumb, higher Kelvin bulbs tend to be more blue in appearance but each bulb is different. It's best to find an example and see for yourself.

[STAT 007]

The guy at your LFS is mistaken. I like the bluer bulbs, particularly 6500Ks and up. 5300K looked WAY too yellow for me. Now I'm running one of both but will go with two 6500Ks when it's time to replace. I'm also thinking about adding a third 55 Watt strip when I get some extra money (yeah, right...hahaha), but that's another story...