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Chihiros RGB VIVID 2 - First impressions video

https://www.ukaps.org/forum/threads/modding-the-chihiros-a-series-to-include-rgb-led.55743/page-2

Should have read this b4 all my comments.. You've been down this road before..

couple of comments for the above photos..
The "muddy" one was running the 3000k diodes as you can see. Really cheap. Basically all yellow phosphor.
Last one is labelled 6500k so I assume just those diodes were on. It's sort of surprising since normally it won't look THAT white.
Doesn't look like any of the other colors were on.
 
rebel said:
Does this mean that you need even more chips like 6500k or 3000k to be in the mix for perfection?
Click to expand...

No, adding any type of white LED just ruins the colour rendition, I've tried. White LED's just end up washing out the other colours, losing saturation, and push everything back to yellow (even cool white LED's).

All the lights I have tried produce the same effect, including the Twinstar 600S, AI Prime Freshwater, Fluval Plant 3.0 and Kessil A360X. They all use white LED's of varying types, and all lack the kind of colour saturation the RGB LED's provide.

I suspect they only way to improve the RGB colour rendition is to broaden the RGB peaks without adding in too much yellow. Maybe by combining other single colour LED's like Royal Blue, Red/Orange, and Green LED's with differing nm centre frequencies, maybe even low output amber and cyan LED's - or maybe future manufacturing techniques that give RGB chips broader output on each channel.

For now though, I think RGB is as good as it gets with current tech as far as I have tested.
 
Wookii said:
I suspect they only way to improve the RGB colour rendition is to broaden the RGB peaks without adding in too much yellow. Maybe by combining other single colour LED's like Royal Blue, Red/Orange, and Green LED's with differing nm centre frequencies, maybe even low output amber and cyan LED's - or maybe future manufacturing techniques that give RGB chips broader output on each channel.

For now though, I think RGB is as good as it gets with current tech as far as I have tested.
Click to expand...

* MIXING LIST
----------------------------------------
LED Blue (470nm) [120°] x1
LED Cyan (500nm) [120°] x1
LED Green (530nm) [120°] x1
LED Amber (590nm) [120°] x1
LED Red (620nm) [120°] x1
----------------------------------------

* SIMULATION DATA
----------------------------------------
Luminous flux : 300 lm
Radiant flux : 1,035 mW
PPF : 4.6 umol/s
TCP : 6250 K
CRI : 90
λp : 472 nm
Color : #FFF9F2
Click to expand...

rgbca.JPG

 
Wookii said:
Not nearly enough green in that graph. Interesting though - what software are you using to model that output - or is it actually measured?

Are you anything to do with SBReef lights by any chance? I’ve seen those graphs on their site.
Click to expand...
Composite w/ ADA RGB..
ADA colors are inverted.
Because of the cyan just more blue-green to green-blue.
Yellow is in short supply.
But.. it is an estimate..
with a color temp of 6350 and a CRI of 90 specs really good.
compositergb.JPG
 
Wookii said:
No, adding any type of white LED just ruins the colour rendition, I've tried. White LED's just end up washing out the other colours, losing saturation, and push everything back to yellow (even cool white LED's).
Click to expand...
The washout effect is due to the eye being more sensitive to yellow and green?

How would you widen the RGB spectra. You'd have to add each individual colours to 'fill' the void isn't it? This could expensive/tedious fast.

Any suggestions on what sort of RGB diodes one could try to DIY a light? My only hangup is that I want it to look schmick but can't find really nice looking heatsinks for my projects. I could put in some 1W RGB diodes to my Chihiros heatsink. It might just be ok if I space them out and drive them at 350ma.
 
rebel said:
The washout effect is due to the eye being more sensitive to yellow and green?
Click to expand...
Partly.. it's just glare..Simulation, just adjusted brightness up
Since all the "colors" are present what's left?
Beam white light to a leaf and it returns green, same w/ a green LED
Same w/ the difference between photographs on a cloudy day vs clear :
glare2.JPG
glare1.JPG
This tank was running 4000k Luminous Devices COB's (thus the yellow) and one 5000K SORRA ( I think)


rebel said:
How would you widen the RGB spectra. You'd have to add each individual colours to 'fill' the void isn't it? This could expensive/tedious fast.
Any suggestions on what sort of RGB diodes one could try to DIY a light? My only hangup is that I want it to look schmick but can't find really nice looking heatsinks for my projects. I could put in some 1W RGB diodes to my Chihiros heatsink. It might just be ok if I space them out and drive them at 350ma.
Click to expand...
Listed that above.. Red,Green,Cyan, Amber, Blue. Exact wavelengths aren't really that important.
Some would skip cyan though PERSONALLY that would be a mistake.

Luxeon developed Lime and PCAmber to avoid the efficiency penalty of green and amber diodes.
They are phosphor converted blue pump diodes. Blue being the most efficient diode.
https://www.digikey.com/en/articles/lime-green-leds-encourage-color-tunable-lighting
Old article and the section on CRI doesn't apply anymore..

Anyways fullish spectrum w/ no whites.
Low K so output needs to be tailered.
91CRI is not judged against d65. D65 would only be 61 so far from "daylight'
You would need the blue output 3x the others

rgbpclime.JPG
 
oreo57 said:
Low K so output needs to be tailered.
Click to expand...
Very interesting!

How does one shift that 3300K to the 7000K range? Increase intensity of the Blues? Honestly I don't understand the concept of K in this 'single colour' LED context. Any links for me to learn more?

Thanks!!
 
rebel said:
Very interesting!

How does one shift that 3300K to the 7000K range? Increase intensity of the Blues? Honestly I don't understand the concept of K in this 'single colour' LED context. Any links for me to learn more?

Thanks!!
Click to expand...
https://en.wikipedia.org/wiki/Color_temperature

Simple version is K is just the temp of a "black" body radiator.
At each temp the color of the emitting light changes.
think "white hot"...

Now diodes,tubes,metal halides are NOT black bodies but the color is matched to a particular Kelvin temperature.
Since the spectrum is derived differently it is really called Correlated Color Temp..Correlated to a K value.
https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/lightsources/whatisCCT.asp
ABOVE link really does explain it all. The closer one gets to the locus the closer the color is err "normal"
Maybe fuller is a better term.
It gets messy since a particular K value is derived from the sum of its "colors" there is really an infinite amount of combinations possible to one K value.
Point is the "K value " or CCT of these punctated light sources can have an infinite amount of looks.
Some will be toned yellow, green, magenta ect.
REAL black body 6500k curve
https://www2.pvlighthouse.com.au/resources/courses/altermatt/The Solar Spectrum/Comparison with blackbody radiation - Plancks law.aspx

6500k tube..just to take a break from LEd's
tropical-wave-lampLG.jpg

And yes you can "cool" (funny since it's really "hotter) a white w/ blue .. warm it w/ red well somewhat.
High k white and red really go to pink not orange. Blame the "holes" in the spectrum
Leading back somewhat to the 7000k /red thing. You avoid, somewhat that yellow/orange intermediate color.
And why RGB is missing the yellow part. And why to increase your palette of tones people (stage/enviromental) add amber or Warm whites.
 
Last edited:
oreo57 said:
Partly.. it's just glare..Simulation, just adjusted brightness up
Since all the "colors" are present what's left?
Beam white light to a leaf and it returns green, same w/ a green LED
Same w/ the difference between photographs on a cloudy day vs clear :
Click to expand...

That's not how it works in practice in an aquarium though. The greens under the RGB LED's are significantly more vibrant and saturated than under the any white LED.
 
Wookii said:
That's not how it works in practice in an aquarium though. The greens under the RGB LED's are significantly more vibrant and saturated than under the any white LED.
Click to expand...
This doesn't exactly address your statement but it has some fun information.

LightStudy

Unlike color matching, the appearance of the light depends not simply on the physical
property of the light but also upon the visual infrastructure of the observers as well. Colorimetry
is based solely upon the spectral characteristics of the light source. But apparent color is not.
The color apperance of a light or of an illuminated object is not determined directly by the
neural signals from the three cone types (long, middle, and short wavelength sensitive cones);
rather, our perception of color represent processed information from the neurons that receive
input from those cone types [22]. Results presented here support the hypothesis that the white
light perception can be enhanced by shifting the chromaticity below the blackbody line and
observers prefer slightly reddish/bluish white light. This will be further explained in section 3.3.
...
So the real observers
perceive light differently with that obtained by the theoretical calculation. This phenomenon is
referred as observer metamerism. Also, the lens pigment density, the cone density and the cone
sensitivity are different for different people, so even same light might look differently for
individual people [27].....
Click to expand...

Sadly concentrates on RGB enhanced White LED's and a warm K.
 
Bit more on "light theory".. Warning, it is a company blurb.
https://www.etcconnect.com/uploaded...ublic/White_Papers/Selador_white_paper_US.pdf
Red, green and blue cannot, in fact, produce extremely saturated color at any hue except red, green and blue. Other colors mixed by RGB tend to appear washed-out or grayish, particularly in the amber-yellow, cyan-turquoise, and deep purple regions .....
The ultimate multiple-color approach Returning to the color-wheel diagrams, one can see that by adding many more colors to the LED mix, the gamut of saturated colors can be greatly expanded within a luminaire. These diagrams show an LED array with seven colors in the mix. The colors are spaced across the spectrum to fill many of the large gaps left by RGB.When the ratios of the various colors of LEDs are managed very carefully in a fixture like this – so that their relative output is well-balanced – color mixing becomes intuitive, and the range of beautiful, deep jewel tones and rich, satisfying pastels can surpass that of other luminaires.
Click to expand...

Each has to decide on what approach they want..
There is no right or wrong here.

Just different..
 
Would anyone know if two RGB Vivid 2 is enough for a 180cm tank? I mostly see people using three but I am wondering if one is enough for a 90cm tank wouldn't two be enough for a 180cm?

Thanks for your input.
 
Would you recommend having 2 of these lights with a 120cm long tank or would you think 1 would be enough
 
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