Can we get a sticky for kelvin colors?

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knifegill

knifegill

Peacock Bass
MFK Member
Sep 19, 2005
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I've found very affordable 5800ºK and 6500ºK bulbs. I wonder, "Will this make my fish look more blue or red?" Can somebody who knows about this briefly list which common numbers cast which approximate hues? Are these significantly different in color? Plants aren't a big deal here, I've just got java moss and a few stragglers of "water weeds". I mostly want to bring out the right colors in my fish. So:

5800ºK= (color description here)

6500ºK= (color description here)

I've found only this:http://www.onstagelighting.co.uk/lighting-design/colour-temperature-guide/
Is there a more specific guide somewhere?
 
The higher the number, the closer the emitted light is to the blue end of the spectrum. The only way to determine what you like is to experiment with different lamps. A sticky that attempts to describe the "redness and blueness" of different lamps isn't going to help you much.
 
one problem however, is that not all bulbs with the same color temperature rating look the same.

eg. Hagen Powerglo and Hagen Aquaglo are both rated at 18,000K

but are very different looking bulbs.

the Aquaglo is dull and pink. the Powerglo is bright and whitish with a hint of blue.

but you would never know that simply by going at the kelvin temperature.
 
anything under 10k will havea yellow tint to it and bring out greens,yellows
 
When you are buying a lamp/tube/bulb/whatever you need to look in several places.

I'll use a Hagen Aqua-Glo as an example:

The front says 18,000K, but this is only a relative measurement of the FINAL COLOR of the light output & is a simple way to express color. Thanks to jcardona1 for the images used below.

Now, turn to the side of the box where it has several graphs/tables of the lamp's light spectrum. First, note the lumens. This is the total AMOUNT of light output, but there is actually no universal measurement standard for lumens (used to be ANSI lumens, but not anymore). The better measurement of output is the LUX table. This is lumens/square meter & a much better judge of light output, because they cant just measure it a millimeter away from the lamp. The 20w, 24" Aqua-Glo I'm looking at is 80 lux. This will vary greatly with wattage & length of the lamp.

The really important graph is the one that looks like a rainbow-colored mountain range. This has many different names (depending on the measurement used for x and y), so I'll just call it "the spectrum graph". This is how the color temp (degrees K) is manipulated to make up the 18,000K you saw on the front. There are usually 3 spikes in this graph, in the red, blue, and green wavelengths. The green spike is usually shifted more toward yellow, though... Plants & corals need UV light around 450nm (nm=wavelength measurement) and under, although your eye will not see all of the UV. Plants also need IR light (also not necessarily visible) above 700nm. The range of hi-UV & low-IR light emitted (the blue & red your eye can see) will determine if the lamp gives off a blueish, reddish or purplish light. It takes a lot of IR to counter the UV, but since IR light produces heat, most lamps will try to use the yellow area of the spectrum (between green & red) to balance the UV. This gives them control of the overall color temp of light output (18,000k in this case) that your eye will see. Consider the Coralife "Colormax" lamp... They dont give you a K measurement to look at because the large visible, IR & UV spikes would not give you an accurate idea of the lamp's color, although it is very nice bright white. Gosh I hope all this helps!

art_maxwell_color_temperatures.gif

headlight color chart.jpg

Kelvin%20Scale.jpg
 
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