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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2016-10-09 21:55:38 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2016-10-09 21:55:38 +0000 |
| commit | 925322ffeda23ca9cf3911ede7aab366859ab996 (patch) | |
| tree | 5630fef6230dadb2f883d4b6e5bf92552bb56c00 /ppm.html | |
| parent | e8b77a65fed29220abe8119e6f337d6979dbf80d (diff) | |
| download | netpbm-mirror-925322ffeda23ca9cf3911ede7aab366859ab996.tar.gz netpbm-mirror-925322ffeda23ca9cf3911ede7aab366859ab996.tar.xz netpbm-mirror-925322ffeda23ca9cf3911ede7aab366859ab996.zip | |
miscellaneous update
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@2834 9d0c8265-081b-0410-96cb-a4ca84ce46f8
Diffstat (limited to 'ppm.html')
| -rw-r--r-- | ppm.html | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/ppm.html b/ppm.html index c5cd1a3f..960c34be 100644 --- a/ppm.html +++ b/ppm.html @@ -6,7 +6,7 @@ </HEAD> <BODY> <H1>ppm</H1> -Updated: 02 November 2013 +Updated: 09 October 2016 <BR> <A HREF="#index">Table Of Contents</A> @@ -92,6 +92,8 @@ in the color universe of which the image is part (the color universe is all the colors in all images to which this image might be compared). +<p>BT.709's range of channel values (16-240) is irrelevant to PPM. + <p>ITU-R Recommendation BT.709 is a renaming of the former CCIR Recommendation 709. When CCIR was absorbed into its parent organization, the ITU, ca. 2000, the standard was renamed. This @@ -100,9 +102,9 @@ clear now that CIE ever sponsored such a standard. <P>Note that another popular color space is the newer sRGB. A common variation on PPM is to substitute this color space for the one specified. +There is no known program to convert between this variation and true PPM. -<p> -Note that a common variation on the PPM format is to have the sample +<p>Note that a common variation on the PPM format is to have the sample values be "linear," i.e. as specified above except without the gamma adjustment. <B>pnmgamma</B> takes such a PPM variant as input and produces a true PPM as output. |