{ "mode": "man", "parameter": "ppmcie", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/ppmcie/1/json", "generated": "2026-05-30T05:14:49Z", "synopsis": "ppmcie [-rec709|-cie|-ebu|-hdtv|-ntsc|-smpte] [-xy|-upvp] [-red rx ry] [-green gx gy] [-blue\nbx by] [-white wx wy] [-size edge] [-xsize|-width width] [-ysize|-height height]\n[-noblack] [-nowpoint] [-nolabel] [-noaxes] [-full]\nAll options can be abbreviated to their shortest unique prefix.", "sections": { "NAME": { "content": "ppmcie - draw a CIE color chart as a PPM image\n\n", "subsections": [] }, "SYNOPSIS": { "content": "ppmcie [-rec709|-cie|-ebu|-hdtv|-ntsc|-smpte] [-xy|-upvp] [-red rx ry] [-green gx gy] [-blue\nbx by] [-white wx wy] [-size edge] [-xsize|-width width] [-ysize|-height height]\n[-noblack] [-nowpoint] [-nolabel] [-noaxes] [-full]\n\nAll options can be abbreviated to their shortest unique prefix.\n\n", "subsections": [] }, "DESCRIPTION": { "content": "ppmcie creates a PPM file containing a plot of the CIE ``tongue'' color chart -- to the ex‐\ntent possible in a PPM image. Alternatively, creates a pseudo-PPM image of the color tongue\nusing RGB values from a color system of your choice.\n\nThe CIE color tongue is an image of all the hues that can be described by CIE X-Y chromatici‐\nty coordinates. They are arranged on a two dimensional coordinate plane with the X chro‐\nmaticity on the horizontal axis and the Y chromaticity on the vertical scale. (You can\nchoose alternatively to use CIE u'-v' chromaticity coordinates, but the general idea of the\ncolor tongue is the same).\n\nNote that the PPM format specifies that the RGB values in the file are from CIE Rec. 709 col‐\nor system, gamma-corrected. And positive. See ppm(5) for details. If you use one of the\ncolor system options on ppmcie, what you get is not a true PPM image, but is very similar.\nIf you display such ppmcie output using a device that expects PPM input (which includes just\nabout any computer graphics display program), it will display the wrong colors.\n\nHowever, you may have a device that expects one of these variations on PPM.\n\nIn every RGB color system you can specify, including the default (which produces a true PPM\nimage) there are hues in the color tongue that can't be represented. For example, monochro‐\nmatic blue-green with a wavelength of 500nm cannot be represented in a PPM image.\n\nFor these hues, ppmcie substitutes a similar hue as follows: They are desaturated and ren‐\ndered as the shade where the edge of the Maxwell triangle intersects a line drawn from the\nrequested shade to the white point defined by the color system's white point. Furthermore,\nunless you specify the -full option, ppmcie reduces their intensity by 25% compared to the\ntrue hues in the image.\n\nppmcie draws and labels the CIE X-Y coordinate axes unless you choose otherwise with options.\n\nppmcie draws the Maxwell triangle for the color system in use on the color tongue. The Max‐\nwell triangle is the triangle whose vertices are the primary illuminant hues for the color\nsystem. The hues inside the triangle show the color gamut for the color system. They are\nalso the only ones that are correct for the CIE X-Y chromaticity coordinates shown. (See ex‐\nplanation above).\n\nppmcie also places a mark at the color system's white point and displays in text the CIE X-Y\nchromaticities of the primary illuminants and white point for the color system. You can turn\nthis off with options, though.\n\nppmcie annotates the periphery of the color tongue with the wavelength, in nanometers of the\nmonochromatic hues which appear there.\n\nFinally, ppmcie displays the black body chromaticity curve for Planckian radiators from 1000\nto 30000 kelvins on the image.\n\nYou can choose from several standard color systems, or specify one of your own numerically.\n\n\nCIE charts, by their very nature, contain a very large number of colors. If you're encoding\nthe chart for a color mapped device or file format, you'll need to use ppmquant or ppmdither\nto reduce the number of colors in the image.\n\n", "subsections": [] }, "OPTIONS": { "content": "", "subsections": [ { "name": "-rec709 -cie -ebu -hdtv -ntsc -smpte", "content": "Select a standard color system whose gamut to plot. The default is -rec709, which\nchooses CIE Rec. 709, gamma-corrected. This is the only color system for which\nppmcie's output is a true PPM image. See explanation above. -ebu chooses the pri‐\nmaries used in the PAL and SECAM broadcasting standards. -ntsc chooses the pri‐\nmaries specified by the NTSC broadcasting system (few modern monitors actually cov‐\ner this range). -smpte selects the primaries recommended by the Society of Motion\nPicture and Television Engineers (SMPTE) in standards RP-37 and RP-145, and -hdtv\nuses the much broader HDTV ideal primaries. -cie chooses a color system that has\nthe largest possible gamut within the spectrum of the chart. This is the same col‐\nor system as you get with the -cie option to John Walker's cietoppm program.\n\n" }, { "name": "-xy", "content": "" }, { "name": "-upvp", "content": "tage of u' v' coordinates is that equal intervals of distance on the u' v' plane\ncorrespond roughly to the eye's ability to discriminate colors.\n" }, { "name": "-red", "content": "specifies the CIE x and y co-ordinates of the red illuminant of a custom color sys‐\ntem and selects the custom system.\n" }, { "name": "-green", "content": "specifies the CIE x and y co-ordinates of the green illuminant of the color system\nand selects the custom system.\n" }, { "name": "-blue", "content": "specifies the CIE x and y co-ordinates of the blue illuminant of the color system\nand selects the custom system.\n" }, { "name": "-white", "content": "specifies the CIE x and y co-ordinates of the white point of the color system and\nselects the custom system.\n" }, { "name": "-size", "content": "Create a pixmap of edge by edge pixels. The default is 512x512.\n" }, { "name": "-xsize|-width", "content": "Sets the width of the generated image to width pixels. The default width is 512\npixels. If the height and width of the image are not the same, the CIE diagram\nwill be stretched in the longer dimension.\n" }, { "name": "-ysize|-height", "content": "Sets the height of the generated image to height pixels. The default height is 512\npixels. If the height and width of the image are not the same, the CIE diagram\nwill be stretched in the longer dimension.\n" }, { "name": "-noblack", "content": "" }, { "name": "-nowpoint", "content": "" }, { "name": "-nolabel", "content": "" }, { "name": "-noaxes", "content": "" }, { "name": "-full", "content": "fied color system.\n\n" } ] }, "SEE ALSO": { "content": "ppmdither(1), ppmquant(1), ppm(5)\n\n", "subsections": [] }, "AUTHOR": { "content": "Copyright (C) 1995 by John Walker (kelvin@fourmilab.ch)\nWWW home page: http://www.fourmilab.ch/\n\nPermission to use, copy, modify, and distribute this software and its documentation for any\npurpose and without fee is hereby granted, without any conditions or restrictions. This\nsoftware is provided ``as is'' without express or implied warranty.\n\n\n\n26th September 1994 PPMCIE(1)", "subsections": [] } }, "summary": "ppmcie - draw a CIE color chart as a PPM image", "flags": [ { "flag": "", "long": null, "arg": null, "description": "Select a standard color system whose gamut to plot. The default is -rec709, which chooses CIE Rec. 709, gamma-corrected. This is the only color system for which ppmcie's output is a true PPM image. See explanation above. -ebu chooses the pri‐ maries used in the PAL and SECAM broadcasting standards. -ntsc chooses the pri‐ maries specified by the NTSC broadcasting system (few modern monitors actually cov‐ er this range). -smpte selects the primaries recommended by the Society of Motion Picture and Television Engineers (SMPTE) in standards RP-37 and RP-145, and -hdtv uses the much broader HDTV ideal primaries. -cie chooses a color system that has the largest possible gamut within the spectrum of the chart. This is the same col‐ or system as you get with the -cie option to John Walker's cietoppm program." }, { "flag": "", "long": null, "arg": null, "description": "" }, { "flag": "", "long": null, "arg": null, "description": "tage of u' v' coordinates is that equal intervals of distance on the u' v' plane correspond roughly to the eye's ability to discriminate colors." }, { "flag": "", "long": null, "arg": null, "description": "specifies the CIE x and y co-ordinates of the red illuminant of a custom color sys‐ tem and selects the custom system." }, { "flag": "", "long": null, "arg": null, "description": "specifies the CIE x and y co-ordinates of the green illuminant of the color system and selects the custom system." }, { "flag": "", "long": null, "arg": null, "description": "specifies the CIE x and y co-ordinates of the blue illuminant of the color system and selects the custom system." }, { "flag": "", "long": null, "arg": null, "description": "specifies the CIE x and y co-ordinates of the white point of the color system and selects the custom system." }, { "flag": "", "long": null, "arg": null, "description": "Create a pixmap of edge by edge pixels. The default is 512x512." }, { "flag": "", "long": null, "arg": null, "description": "Sets the width of the generated image to width pixels. The default width is 512 pixels. If the height and width of the image are not the same, the CIE diagram will be stretched in the longer dimension." }, { "flag": "", "long": null, "arg": null, "description": "Sets the height of the generated image to height pixels. The default height is 512 pixels. If the height and width of the image are not the same, the CIE diagram will be stretched in the longer dimension." }, { "flag": "", "long": null, "arg": null, "description": "" }, { "flag": "", "long": null, "arg": null, "description": "" }, { "flag": "", "long": null, "arg": null, "description": "" }, { "flag": "", "long": null, "arg": null, "description": "" }, { "flag": "", "long": null, "arg": null, "description": "fied color system." } ], "examples": [], "see_also": [ { "name": "ppmdither", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/ppmdither/1/json" }, { "name": "ppmquant", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/ppmquant/1/json" }, { "name": "ppm", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/ppm/5/json" } ] }