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Hermit
Registered: May 2008
Posts: 208 |
Where possibly C64 colour-codes came from
Hi Guys.
I wonder if any of you have ever noticed the similarity between electrical Resistor colour-codes and C64 colour-codes. I was surprised in electrical school how easily I could memorize resistor colours for the 1st time. If you look at my little comparison diagram, you won't be surprised either.
The only difference between resistor colour-codes and C64 colour codes is 2 pairs of swapped values, and 4 values out of 10 are pretty the same. There's no similarity at all in only 2 colours.
Maybe the C64 palette inherited some colours unconsciously or consciously by the VIC 6569 designers who must have been quite familiar with resistor colour-codes. You know, there's a symptom called synesthesia, and I can easily imagine that, for VIC 6569 designers some learnt colours meant numbers back & forth by first thoughts/feelings.
http://en.wikipedia.org/wiki/Synesthesia
Anyway, there's another story here on this page I found in the past:
http://www.pepto.de/projects/colorvic/
It seems designers could nearly freely put any colours they wanted by intuition. Here's a quotation referring to the fact:
"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.
I believe that Commodore actually got a patent on this technique. It was certainly superior to the Apple or Atari approach at the time, as they ended up with whatever colors that came out ours allowed the designer to freely select Hue, Saturation and Luminance."
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Mr. SID
Registered: Jan 2003
Posts: 424 |
I think this is just coincidence. The resistor colors are ordered by hue.
The C64 color ordering has a different interesting property. You can XOR the color codes for red/green/blue and you'll get the proper mixed color.
Red + Green = %0010 XOR %0101 = %0111 = Yellow
Red + Blue = %0010 XOR %0110 = %0100 = Magenta
Green + Blue = %0101 XOR %0110 = %0011 = Cyan
I think you'll have a hard time arguing that that's a coincidence... ;) |
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Monte Carlos
Registered: Jun 2004
Posts: 355 |
Do you know an application of the xor property or an example concerning demo effects? Would be interesting...
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Axis/Oxyron
Account closed
Registered: Apr 2007
Posts: 91 |
Fantasia/Oxyron: http://noname.c64.org/csdb/release/?id=3497. As far as I remember Slide used XOR to build the mixing colors for the rasterbars in the intro. |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
I think it's just a coincidence. The first 8 colors are just a composite version of an RGB palette, no big surprises there. On VIC20 (which seems to use a similar color circuit as the C64) the colors 10-15 share the same hue as the colors 2-7. Only colors 8 and 9 seem to be an exception, probably because colors 0 and 1 got some extra hardwired circuit to produce black and white luminances + no chrominance.
For C64 the devs removed some "useless" colors like dark cyan, dark purple and dark yellow to introduce shades of grey. Rest stayed quite similar if you ignore the different luminances.
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Cybortech
Registered: Jan 2009
Posts: 14 |
i think the $0A colour have a gay name called light red. the NORMAL name is _PINK_ |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
It has the same chrominance like normal red ($02). Same for dark and light green ($05, $0d) and dark and light blue ($06, $0e).
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Cybortech
Registered: Jan 2009
Posts: 14 |
but then $09 is brown and $08 is light brown. : ) |
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Mr. SID
Registered: Jan 2003
Posts: 424 |
Nope, they have different hues, (135 and 157.5 degrees). |
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enthusi
Registered: May 2004
Posts: 675 |
I dont even think that there are that many different colors you can come up with. Its hard to find even 16 colors that dont look too much alike...
Same for EGA and such.
(http://wiki.scummvm.org/index.php/AGI/Palettes) |
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linde
Registered: Jul 2006
Posts: 47 |
A friend told me that the that the 16 color PC CGA palette has a similar property about mixing -- if you OR the colors together, you get a mix.
Apparently it has two 8-color bright/halfbright palettes that work this way. So does the ZX spectrum. |
