Editing MOS Technology VIC-II (section)

===Colors===
[[Image:VIC-II color map.svg|thumb|192px|right|The VIC-II chip has a fixed 16-color palette, shown above.]]

In multicolor character mode (160×200 pixels, which most games use) characters have 4×8 pixels (the characters are still approximately square since the pixels are double width) and 4 colors out of 16 colors. Three of the colors are the same for the entire screen (the background color, multicolor 1, and multicolor 2 registers), while the remaining color can be set individually for every such 4×8 pixel area as defined in color RAM. Sprites in multicolor mode (12×21 pixels) have three colors plus transparency: two colors shared among all sprites and one individual. Artists pick shared colors such that the combination with individual colors leads to a colorful impression. Some games reload shared colors during the raster interrupt; for example, the game ''[[Turrican II: The Final Fight|Turrican II's]]'' underwater area (which was vertically distinct) has different colors. Others, such as [[Epyx]]'s ''[[Summer Games (video game)|Summer Games]]'' and ''[[COMPUTE!'s Gazette]]'''s ''Basketball Sam & Ed'', overlay two high-resolution sprites to allow two foreground colors to be used without sacrificing horizontal resolution [https://web.archive.org/web/20071001045256/http://home.arcor.de/cybergoth/gamesa/summer1interview1.html]. Of course, this technique reduces the number of available sprites by half.

On [[PAL]] C64s, the PAL [[Analog delay line|delay line]] in the monitor or TV which averages the color [[hue]], but not the brightness, of consecutive screen lines can be used to create seven nonstandard colors by alternating screen lines showing two colors of identical brightness. There are seven such pairs of colors in the VIC chip.<ref>{{Cite web |title=Luma-Driven Graphics on the C64 |url=https://kodiak64.com/blog/luma-driven-graphics-on-c64}}</ref>

The C64's team did not spend much time on mathematically computing the 16 color palette. Robert Yannes, who was involved with the development of the VIC-II, said: <blockquote>''I'm afraid that not nearly as much effort went into the color selection as you think. Since we had total control over hue, saturation and luminance, we picked colors that we liked. In order to save space on the chip, though, many of the colors were simply the opposite side of the color wheel from ones that we picked. This allowed us to reuse the existing resistor values, rather than having a completely unique set for each color.<ref>{{cite web
 | last1      = Timmermann
 | first1     = Philip
 | title      = Commodore VIC-II Color Analysis (Preview)
 | url        = http://www.pepto.de/projects/colorvic/2001/
 | accessdate = 11 February 2018}}</ref>''</blockquote>

Early versions of the VIC-II used in PAL C64s have a different color palette than later revisions.<ref>{{cite web|last1=Sjöstedt|first1=Ilkka|title=Old VIC-II Colors and Color Blending|url=https://ilesj.wordpress.com/2016/03/30/old-vic-ii-colors-and-color-blending/|website=ilesj's blog|date=30 March 2016 |accessdate=11 February 2018}}</ref>

The full palette of sixteen colors is generated based on variations of [[YPbPr]] signals as shown below:

{| class="wikitable sortable" style="border-style: none;" border="1" cellpadding="5"
! style="width: 135pt;"| Number — name || [[YPbPr|Y]] || [[YPbPr|Pb]] (rel.) || [[YPbPr|Pr]] (rel.)
|- style="color: white; background: #000;"
|| 0 — black || 0 || 0 || 0
|- style="color: black; background: #fff;"
|| 1 — white || 1 || 0 || 0
|- style="color: white; background: #883932;"
|| 2 — red || 0.3125 || −0.3826834 || 0.9238795
|- style="color: white; background: #67b6bd;"
|| 3 — cyan || 0.625 || 0.3826834 || −0.9238795
|- style="color: white; background: #8b3f96;"
|| 4 — purple || 0.375 || 0.7071068 || 0.7071068
|- style="color: white; background: #55a049;"
|| 5 — green || 0.5 || −0.7071068 || −0.7071068
|- style="color: white; background: #40318d;"
|| 6 — blue || 0.25 || 1 || 0
|- style="color: black; background: #bfce72;"
|| 7 — yellow || 0.75 || −1 || 0
|- style="color: white; background: #8b5429;"
|| 8 — orange || 0.375 || −0.7071068 || 0.7071068
|- style="color: white; background: #574200;"
|| 9 — brown || 0.25 || −0.9238795 || 0.3826834
|- style="color: white; background: #b86962;"
|| 10 — light red || 0.5 || −0.3826834 || 0.9238795
|- style="color: white; background: #505050;"
|| 11 — dark grey || 0.3125 || 0 || 0
|- style="color: white; background: #787878;"
|| 12 — medium grey || 0.46875 || 0 || 0
|- style="color: black; background: #94e089;"
|| 13 — light green || 0.75 || −0.7071068 || −0.7071068
|- style="color: white; background: #7869c4;"
|| 14 — light blue || 0.46875 || 1 || 0
|- style="color: white; background: #9f9f9f;"
|| 15 — light grey || 0.625 || 0 || 0
|}

<!-- Format color contrast with Commodore colors:
     While Y ≤ 0.625 => Use white text;
     while Y > 0.625 => Use black text;
     /* See Commodore 16/Commodore Plus/4 inside the color palette article or MOS Technology TED */
-->