File:Blackbody sRGB quantal-units.png
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DescriptionBlackbody sRGB quantal-units.png |
English: Example of a sRGB-rendered blackbody color spectrum to illustrate the scaling problems energy versus quantal units. This image should be examined for scientific validity by an expert, and in the positive case replaced by a scalable (albeit larger) SVG file. This file is a response to File:Blackbody-sRGB.svg. The colors are generated via the following steps: 1. Calculate the Planck spectral energy density as a function of the wavelength for a range of temperatures. 2. Calculate the CIE XYZ 1931 tristimulus (version modified by Judd 1951 and Vos 1978, [1]), weighted by reciprocal wavelength for quantal scaling (with λ0=500 nm is arbitrary chosen as reference to keep the ratio near 1), for the spectra in each temperature step:
3. convert into sRGB using the corresponding matrices (this requires some rescaling to avoid oversaturation of any color channel). The sRGB gamma correction is the done for all C = R, G, B as follows:
To get quantal weighting, the XYZ color-matching functions are divided by the wavelength (relative to 500 nm to keep the order of magnitude near 1). Finally, 3. convert into sRGB using the corresponding matrices (this requires some rescaling to avoid oversaturation of any color channel). The result is written into an RGB palette file which can than be visualized by gnuplot. In contrast to File:Blackbody sRGB energy-units.png the white point is near 5300 K implying a slightly bluish-white hue of the Sun (5800 K), which contradicts everyday experience. |
Date | |
Source | Own work |
Author | SiriusB |
Other versions | File:Blackbody sRGB energy-units.png |
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This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication. | |
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.
http://creativecommons.org/publicdomain/zero/1.0/deed.enCC0Creative Commons Zero, Public Domain Dedicationfalsefalse |
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 20:59, 3 September 2011 | 2,000 × 200 (5 KB) | SiriusB (talk | contribs) | Applied gamma correction | |
09:45, 3 September 2011 | 2,000 × 200 (5 KB) | SiriusB (talk | contribs) | Cropped the margins | ||
09:25, 3 September 2011 | 2,000 × 200 (5 KB) | SiriusB (talk | contribs) | {{Information |Description ={{en|1=Example of a sRGB-rendered blackbody color spectrum to illustrate the scaling problems energy versus quantal units. This image should be examined for scientific validity by an expert, and in the positive case replaced |
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