Chromaticity - Revision history

Cmditradmin at 20:44, 3 September 2009

2009-09-03T20:44:23Z

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	~~== Chromaticity ==~~

	Engineers and designers have very specific requirements for light emitting and light absorbing materials. They frequently use a color measurement system called tristimulus to precisely specify any possible color, even those that can not be described with a simple wavelength.		Engineers and designers have very specific requirements for light emitting and light absorbing materials. They frequently use a color measurement system called tristimulus to precisely specify any possible color, even those that can not be described with a simple wavelength.

24.19.10.162: /* External Links */

2009-08-27T00:33:28Z

External Links

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	[http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colper.html#c2 Hyperphysics materials about chromaticity]		[http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colper.html#c2 Hyperphysics materials about chromaticity]

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	<table id="toc" style="width: 100%">		<table id="toc" style="width: 100%">
	<tr>		<tr>

Cmditradmin: /* Chromaticity */

2009-08-26T21:57:01Z

Chromaticity

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	== Chromaticity ==		== Chromaticity ==

	Engineers and designers have very specific requirements for light emitting and light absorbing materials. They frequently ~~used~~ a system called tristimulus ~~system~~ to precisely specify any possible color, even those that can not be described with a simple wavelength.		Engineers and designers have very specific requirements for light emitting and light absorbing materials. They frequently use a color measurement system called tristimulus to precisely specify any possible color, even those that can not be described with a simple wavelength.

	=== Tristimulus measurement and chromaticity diagrams ===		=== Tristimulus measurement and chromaticity diagrams ===

Cmditradmin at 21:55, 26 August 2009

2009-08-26T21:55:01Z

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	<td style="text-align: left; width: 33%">[[Color\|Previous Topic]]</td>		<td style="text-align: left; width: 33%">[[Color\|Previous Topic]]</td>
	<td style="text-align: center; width: 33%">[[Main_Page#Luminescence and Color\|Return to Luminescence Menu]]</td>		<td style="text-align: center; width: 33%">[[Main_Page#Luminescence and Color\|Return to Luminescence Menu]]</td>
	~~<td style="text-align: right; width: 33%">[[Additive and Subtractive Color Mixing\|Next Topic]]</td>~~
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	<td style="text-align: left; width: 33%">[[Color\|Previous Topic]]</td>		<td style="text-align: left; width: 33%">[[Color\|Previous Topic]]</td>
	<td style="text-align: center; width: 33%">[[Main_Page#Luminescence and Color\|Return to Luminescence Menu]]</td>		<td style="text-align: center; width: 33%">[[Main_Page#Luminescence and Color\|Return to Luminescence Menu]]</td>
	~~<td style="text-align: right; width: 33%">[[Additive and Subtractive Color Mixing\|Next Topic]]</td>~~
	</tr>		</tr>
	</table>		</table>

Cmditradmin: /* Tristimulus measurement and chromaticity diagrams */

2009-08-26T21:54:35Z

Tristimulus measurement and chromaticity diagrams

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	Around the horseshoe shaped periphery are the pure saturated colors , beginning with 400nm (violet) and going around to 700 nm (red). Those are the colors of the visible spectrum. The straight line across the bottom are colors that come from the non-spectral mixing of violet and red, they do not correspond to a single wavelength.		Around the horseshoe shaped periphery are the pure saturated colors , beginning with 400nm (violet) and going around to 700 nm (red). Those are the colors of the visible spectrum. The straight line across the bottom are colors that come from the non-spectral mixing of violet and red, they do not correspond to a single wavelength.
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	[[Image:300px-CIExy1931_twocolors.png\|thumb\|300px\|]]		[[Image:300px-CIExy1931_twocolors.png\|thumb\|300px\|]]

Cmditradmin: /* Plotting CIE values */

2009-08-26T21:54:04Z

Plotting CIE values

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	<br clear='all'>=== Incandescent light sources ===		<br clear='all'>
			=== Incandescent light sources ===

	[[Image:533px-PlanckianLocus.png\|thumb\|300px\|]]		[[Image:533px-PlanckianLocus.png\|thumb\|300px\|]]

Cmditradmin: /* Tristimulus measurement and chromaticity diagrams */

2009-08-26T21:53:54Z

Tristimulus measurement and chromaticity diagrams

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	'''z = Z/(X + Y + Z)'''		'''z = Z/(X + Y + Z)'''

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	[[Image:Cie_chromaticity_diagram_wavelength.png\|thumb\|300px\|]]		[[Image:Cie_chromaticity_diagram_wavelength.png\|thumb\|300px\|]]

Cmditradmin: /* Incandescent light sources */

2009-08-26T18:57:00Z

Incandescent light sources

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	The dominant color designation is then obtained by extrapolating the line in the opposite direction to a saturated spectral color it is given as "complementary dominant wavelength 495 nm" or 495c. The color of this apple is therefore the visual equivalent of a mixture of white light and the 495c saturated purple-red in the intensity ratio of the distances p to q shown in the figure with a purity of 100p/(p + q) percent.		The dominant color designation is then obtained by extrapolating the line in the opposite direction to a saturated spectral color it is given as "complementary dominant wavelength 495 nm" or 495c. The color of this apple is therefore the visual equivalent of a mixture of white light and the 495c saturated purple-red in the intensity ratio of the distances p to q shown in the figure with a purity of 100p/(p + q) percent.

	=== Incandescent light sources ===
			<br clear='all'>=== Incandescent light sources ===

	[[Image:533px-PlanckianLocus.png\|thumb\|300px\|]]		[[Image:533px-PlanckianLocus.png\|thumb\|300px\|]]
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	The color of daylight changes over the course of a day. LED designers could make the color of their devices change during the day to better match the daylight experience. Some white lights feel “warmer “ or “colder “depending on the color balance. LEDs will have the same descriptives.		The color of daylight changes over the course of a day. LED designers could make the color of their devices change during the day to better match the daylight experience. Some white lights feel “warmer “ or “colder “depending on the color balance. LEDs will have the same descriptives.

	== External Links ==		== External Links ==

Cmditradmin at 18:56, 26 August 2009

2009-08-26T18:56:14Z

← Older revision		Revision as of 11:56, 26 August 2009
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	</tr>		</tr>
	</table>		</table>

			== Chromaticity ==

	Engineers and designers have very specific requirements for light emitting and light absorbing materials. They frequently used a system called tristimulus system to precisely specify any possible color, even those that can not be described with a simple wavelength.		Engineers and designers have very specific requirements for light emitting and light absorbing materials. They frequently used a system called tristimulus system to precisely specify any possible color, even those that can not be described with a simple wavelength.

	== Tristimulus measurement and chromaticity diagrams ==		=== Tristimulus measurement and chromaticity diagrams ===

	The tristimulus color measurement system is based on visually matching a color under standardized conditions against the three primary colors, red, green, and blue; the three results are expressed as X, Y, and Z, respectively, and are called '''tristimulus''' values		The tristimulus color measurement system is based on visually matching a color under standardized conditions against the three primary colors, red, green, and blue; the three results are expressed as X, Y, and Z, respectively, and are called '''tristimulus''' values
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	Around the horseshoe shaped periphery are the pure saturated colors , beginning with 400nm (violet) and going around to 700 nm (red). Those are the colors of the visible spectrum. The straight line across the bottom are colors that come from the non-spectral mixing of violet and red, they do not correspond to a single wavelength.		Around the horseshoe shaped periphery are the pure saturated colors , beginning with 400nm (violet) and going around to 700 nm (red). Those are the colors of the visible spectrum. The straight line across the bottom are colors that come from the non-spectral mixing of violet and red, they do not correspond to a single wavelength.
			[[Image:300px-CIExy1931_twocolors.png\|thumb\|300px\|]]

			=== Plotting CIE values ===

			By plotting the calculated x = 0.245 and y = 0.421 of the emerald-green pigment at point E on the chromaticity diagram and extending a line through it from the achromatic point W to the saturated spectral boundary, it is possible to determine the dominant wavelength of the pigment color, 511.9 nm. Emerald green is not a pure color. But it can be made by mixing the pure color with wavelength 511.9nm with white light.

			The color of the pigment is the visual equivalent of adding white light and light of 511.9 nm in amounts proportional to the lengths '''n''' (the distance between points '''E''' and '''W''') and '''m''' (the distance between '''E''' and the point of the dominant wavelength) in the figure. The saturation or purity equals 100n/(m + n) percent - in this case, 22.8 percent. A purity of 100 percent corresponds to a pure saturated spectral color and 0 percent to the achromatic colors (white, gray, and black)


			Another example, a red apple marked '''R''' on the diagram. If you connect the line through '''w''' and '''R''' it intersects the bottom line which are not pure spectral colors. In this case this shade of red must be defined in terms of the complementary color on the opposite side of the achromatic point.

			The dominant color designation is then obtained by extrapolating the line in the opposite direction to a saturated spectral color it is given as "complementary dominant wavelength 495 nm" or 495c. The color of this apple is therefore the visual equivalent of a mixture of white light and the 495c saturated purple-red in the intensity ratio of the distances p to q shown in the figure with a purity of 100p/(p + q) percent.

			=== Incandescent light sources ===

			[[Image:533px-PlanckianLocus.png\|thumb\|300px\|]]
			Light from incandescent sources falls on the solid curve marked with temperatures in this figure, following the sequence saturated red to saturated orange to unsaturated yellow to white to unsaturated bluish white for an infinite temperature.

			The points A, B, and C on the curve are CIE standard illuminants that approximate, respectively, a 100-watt incandescent filament lamp at a color temperature of about 2,850 K, noon sunlight (about 4,800 K), and average daylight (about 6,500 K)

			The color of daylight changes over the course of a day. LED designers could make the color of their devices change during the day to better match the daylight experience. Some white lights feel “warmer “ or “colder “depending on the color balance. LEDs will have the same descriptives.
	== External Links ==		== External Links ==

Cmditradmin at 18:53, 26 August 2009

2009-08-26T18:53:14Z

← Older revision		Revision as of 11:53, 26 August 2009
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	</table>		</table>

			Engineers and designers have very specific requirements for light emitting and light absorbing materials. They frequently used a system called tristimulus system to precisely specify any possible color, even those that can not be described with a simple wavelength.

	== Tristimulus measurement and chromaticity diagrams ==		== Tristimulus measurement and chromaticity diagrams ==