frequency of a specific colour...

[hiverjr]

the basic EMS chart is not detailed enough to tell me the wavelength/frequency of specific colours. is there any way(without conducting a lab experiment), such as an already existant chart, that i can find these things? key word being "specific". i would very much like to also find the wavelength of my favourite colour as well ...vermillion. any tips, tricks, calculations or perhaps LINKS?

 

[pico]

File:Rendered Spectrum.png - Wikipedia, the free encyclopedia

File:EM spectrum.svg - Wikipedia, the free encyclopedia

 

[BradtheRad]

Look into diffraction gratings (rainbow window). This can become a low-cost spectroscope.

Edmund Scientific did (or does) have one of these, mounted in a cardboard slide. Included free with any order. It was interesting to see spectrographic displays generated by a light.

To figure out the wavelength you're looking at, you might need to get a simultaneous view of known wavelengths. This might be fluorescent tubes, sodium light, strontium light, etc.

Another possibility is simultaneous views of led's of known wavelength. See if the LEDmuseum website has more info:

The Led Museum

 

[DartPlayer170]

Color Theory and Wavelength

Good question: There are numerous problems with giving a concrete and accurate answer to this question. Believe it or not, color theory is perhaps more art than science. Or at least, there are many issues with any version of color theory that you might subscribe to. If you're looking for a color chart on the Internet, then you have an additional problem. Everybody has monitors that are not calibrated the same with respect to hues. Ie: they all have tint adjustments. Not to mention that some aspects of color classification are subjective.

Still, I have been looking for the same answer and found none. However, by combining pieces of information from various sources I managed to come up with a solution. Albeit, I don't guarantee the accuracy. There were disagreements from various sources even on simple color vs wavelength data. But with a little bit of creative jerry-rigging I have a formula:

Y = -0.000045 * x^3 + 0.0167 * x^2 - 2.1886 * x + 660.71
where Y is the wavelength of the color in nm and x is the RGB Hue Phase Angle in degrees.

You can lookup color hue phase angles from this site: Red • RGB Color Wheel & Color Map • Color • Procato.com
or you can calculate the phase angle from the RGB values with a little math.
Note: only phase angles from 0 to 270 degrees are valid. Colors between 270 and 360 degrees are not part of the rainbow. They are created by combining red and blue. But they do not have wavelengths associated with them because there is no real saturated sources of them.

Here are some data from the formula for common colors:

Violet 401
Blue Violet 423
Indigo 442
Persian Blue 460
Blue 475
Phtalo Blue 489
Sapphire Blue 501
Cobalt Blue 512
Azure 521
Cornflower Blue 203
Cerulean 535
Arctic Blue 541
Cyan 545
Opal 549
Turquoise 552
Aquamarine 554
Spring Green 556
Sea Green 558
Malachite Green 559
Emerald Green 560
Green 561
Sap Green 562
Harlequin 563
Pistachio 564
Charteuse Green 566
Spring Bud 569
Lime Green 572
Apple Green 575
Yellow 580
Gold 585
Amber 592
Gamboge 600
Orange 609
Tangelo 619
Vermilion 631
Scarlet 645
Red 661