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→External links: {{IBM personal computers}} |
Remove link to manualslib per WP:LINKVIO; they're not the original publisher of this manual, they don't own the rights, and they near-exclusively upload copyvios. (The spam blacklist folks are trying to clear these out so they can blacklist the entire site) |
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Color 6 is treated specially; normally, color 6 would become ''dark yellow'', as seen to the left, but in order to achieve a more pleasing brown tone, special circuitry in most RGBI monitors, starting with the IBM 5153 color display,<ref>International Business Machines Corporation (1983): IBM Personal Computer XT Technical Reference Manual, pages D-42 to D-43.</ref> makes an exception for color 6 and changes its hue from dark yellow to brown by reducing the analogue green signal's amplitude. The exact amount of reduction differed between monitor models: the original IBM 5153 Personal Computer Color Display reduces the green signal's amplitude by about one third,<ref>{{cite web|url=https://forum.vcfed.org/index.php?threads/representing-ibm-5153-color-output-more-accurately.1234458/ |title=Representing IBM 5153 color output more accurately | Vintage Computer Federation Forums |publisher=Forum.vcfed.org |date= December 2021|accessdate=2022-03-21}}</ref> while the IBM 5154 Enhanced Color Display internally converts all 4-bit RGBI color numbers to 6-bit ECD color numbers,<ref name=":5">{{Cite book|url=http://minuszerodegrees.net/oa/OA%20-%20IBM%20Enhanced%20Color%20Display%20(5154).pdf|title=IBM Personal Computer Hardware Reference Library: IBM Enhanced Color Display |page=4}}</ref> which amounts to halving the green signal's amplitude. The Tandy CM-2,<ref>{{Cite book|url=https://archive.org/details/tandy-service-manual-cm-2-color-monitor-26-3212|title=Tandy CM-2 Color Monitor Service Manual|page=48}}</ref> CM-4<ref>{{Cite book|
This "RGBI with tweaked brown" palette was retained as the default palette of later PC graphics standards such as [[Enhanced Graphics Adapter|EGA]] and [[Video Graphics Array|VGA]], which can select colors from much larger gamuts, but default to these until reprogrammed.
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