Mountain's Green Water Options

[CyberET]

u no understand me
what i mean is the lighting color
use 6500 Kelvin
not 10000 Kelvin

[dennis]

u no understand me

Hehehehehe ........ this is funny!

When I was schooling, it actually took me awhile to accept that the meansurement of "colour" of light being measured in degree of hotness too.

[mountain]

u no understand me
what i mean is the lighting color
use 6500 Kelvin
not 10000 Kelvin

*faint* pai say pai say

[Jos Nana]

u no understand me
what i mean is the lighting color
use 6500 Kelvin
not 10000 Kelvin

Kelvin is refering to the intensity of the light spectrum. Not temperature. MH light of the same wattage will emit the same amount of heat.

The higher the Kelvin value, the better cos it will penetrate deeper into the water.

[CyberET]

Kelvin is refering to the intensity of the light spectrum. Not temperature. MH light of the same wattage will emit the same amount of heat.

The higher the Kelvin value,  the better cos it will penetrate deeper into the water.

oh.. i see.. so as PL light penetration is lower, one requires higher Kelvin for PL as compared to MH? would the green produced be similar to MH @ 6500K, or sunlight?

[Jos Nana]

oh.. i see.. so as PL light penetration is lower, one requires higher Kelvin for PL as compared to MH? would the green produced be similar to MH @ 6500K, or sunlight?

PL lights and flourescent tubes (Dupla/Arcadia etc..) also have the same kelvin value at the beginning. However, the rate of depletion is very fast. The Green water you get now with new tubes will be very different one month later.

MH tubes maintains its spectrum longer. For MH tubes, replacement period is about 1 year. Flourescent and PL tubes - 3 months max.

[dennis]

Kelvin is refering to the intensity of the light spectrum. Not temperature. MH light of the same wattage will emit the same amount of heat.

The higher the Kelvin value,  the better cos it will penetrate deeper into the water.

I think you might be mistaken. Kelvin is a temperature scale ...... below is an extract from http://www.infoplease.com/ce6/sci/A0827335.html

****** Extract Starts *********

Kelvin temperature scale, a temperature scale having an absolute zero below which temperatures do not exist. Absolute zero, or 0K, is the temperature at which molecular energy is a minimum, and it corresponds to a temperature of -273.15° on the Celsius temperature scale. The Kelvin degree is the same size as the Celsius degree; hence the two reference temperatures for Celsius, the freezing point of water (0°C), and the boiling point of water (100°C), correspond to 273.15K and 373.15K, respectively. When writing temperatures in the Kelvin scale, it is the convention to omit the degree symbol and merely use the letter K. The temperature scale is named after the British mathematician and physicist William Thomson Kelvin, who proposed it in 1848. Another absolute temperature scale, the Rankine temperature scale, is used by some engineers. See also Fahrenheit temperature scale.

****** Extract Ends ***********

When a light is rated in Kelvin it's usually refers to the color spectrum of the light it emmits rather then it's intensity, I think the intensity is measured in something call footcandles or lux. The following is an extract from http://members.shaw.ca/jimht03/light.html.

******* Extract Starts **********

Black Body Illuminants
The first group of light sources are the black body illuminants. These are materials that produce light when they are heated. The sun is a black body illuminant, as is a candle flame. The color of light of these types of sources can be characterized by their Kelvin temperature. Note that this temperature has nothing to do with how "hot" a light source is - just with the color of its light. A light source with a low Kelvin temperature is very red. One with a high Kelvin temperature is very blue. More accurately, when we see two light sources side by side in a scene, the higher Kelvin light appears more blue, and the lower Kelvin light appears more red. Its all relative.

Black body illuminants produce a fairly even, continuous spectrum of colors, and so are perceived as "white" by our visual sense. Therefore, in the absence of comparative light sources in our scene, these should be rendered with warm, nearly white lights.

Below is a chart of some common Kelvin Light Source temperatures coupled with their RGB Equivalents. These equivalents were arrived arbitrarily - I eyeballed them. There were a couple of converters I found online, each taking a different approach. One of them colored the sources by reference - you input a Kelvin temperature that you want to be "white" and the temperature to convert into an RGB value. Visually, however, the results were disappointing. They were scientifically correct, but failed to take into account the adaptability of the human visual sense. The other converter did even worse, ending up with greenish shades in the 4500K range that black body illuminants are incapable of creating. So, the alternative was to use my eye and judgment to arrive at these values.

Light Source...........Kelvin temperature...............R G B Values Color
Candle.......................1900....................................255, 147, 41
40W Tungsten.............2600....................................255, 197, 143
100W Tungsten...........2850....................................255, 214, 170
Halogen.....................3200....................................255, 241, 224
Carbon Arc................5200....................................255, 250, 244
High Noon Sun...........5400....................................255, 255, 251
Direct Sunlight...........6000....................................255, 255, 255
Overcast Sky.............7000....................................201, 226, 255
Clear Blue Sky..........20000...................................64, 156, 255

******** Extract Ends **************

Do go to the hyperlink attached to see the colour chart and images used to illustrate the spectrum. BTW I think the last entry in the above table is wrong, bright blue light should be 10,000K instead of 20,000K.

Incidentally I also have a site http://www.automatedaquariums.com/mw_m700.htm for a meter which reads light intensitywhich is meant for a aquarium.

Here a thread in another forum where they discuss alittle about the spectrum and intensity require to achieve photosynthesis. Well actaully just some arguement that is The link is http://fins.actwin.com/aquatic-plants/mont...7/msg00378.html Do read the other threads, they do make good reading.

This post has been edited by dennis: Fri, 26 Dec 2003 10:41 am

[Jos Nana]

Reply to dennis :-

Thank you for your info.

If base on the info from the extract, then 373.15K = 100 degrees C. Then 6500K = 1741 degrees C ! It don't seems to make sense. As mention in the later part of your extract, in Aquarium lighting, K denotes the colour spectrum rather than the temperature.

Yes, the essence in relation to K is the correct mix of Red, Green and Blue spectrum. I have use a loose word "intensity" to simplified things. Guess its was a bad choice of words.

For Green water, it needs more and undisturbed Blue spectrum, Thus a higher K value tube is better.

Many thanks for your info. Will keep in file.

[square_guy]

Reply to dennis :-

Thank you for your info.

If base on the info from the extract, then 373.15K = 100 degrees C. Then 6500K  = 1741 degrees C !  It don't seems to make sense. As mention in the later part of your extract, in Aquarium lighting, K denotes the colour spectrum rather than the temperature.

Yes, the essence in relation to K is the correct mix of Red, Green and Blue spectrum. I have use a loose word "intensity" to simplified things. Guess its was a bad choice of words.

For Green water, it needs more and undisturbed Blue spectrum, Thus a higher K value tube is better.

Many thanks for your info. Will keep in file.

not really relevant (more like point of interest), kelvin is an actual scientific temperature scale. it is absolute, so zero kelvin is the lowest temperature possible in the physical world. using kelvin to grade colour temperature stems (i believe) from the fact that body giving out certain degree of heat will exhibit certain colour. in fact some intruments can measure the temperature of something purely on its colour. a body glowing red will be of certain kelvin, likewise for a body glowing blue.

so we have the common terms such as red-hot or white-hot.

hope i got most things corret

[dennis]

If base on the info from the extract, then 373.15K = 100 degrees C. Then 6500K  = 1741 degrees C !  It don't seems to make sense.

Yah I understand what you mean. Thats why in the initial post I said that I have problem accepting Kelvin as a measurement for the color of light while I was in school until I saw a documentary on TV where they heat some steel pipes as an experiment, but for that simple experiment they could only reach white or white-hot as square_guy put it

This post has been edited by dennis: Fri, 26 Dec 2003 2:46 pm

[Seacucumber]

who is this Kelvin guy anyway??

This post has been edited by g-string: Fri, 26 Dec 2003 6:34 pm

[LASERGUY]

who is this Kelvin guy anyway??

The one who sold you those G-STRING !!!!

This post has been edited by LASERGUY: Fri, 26 Dec 2003 6:56 pm

[HappyBuddha]

who is this Kelvin guy anyway??

Kelvin is actually his last name...



Whoa, he helped laid the world's first transatlantic g-string?

Okay, so now I know who Kelvin is... and that Kelvin refers to the colour spectrum a light source emits. But how do you explain "intensity". Go to a dark room, and light up a candle. The room is now dimly lit. Now, light up 64 candles. The room is now a lot brighter. How do you measure this brightness?

[mountain]

uncle me onli 26yrs old.. dun talk spaceship to me lei.. dun understand

[mountain]

haha.. give u chance make a lousy guess...