Re: Color Reference of NTSC Formula?

["Bryan Parkoff" <nospam@nospam.com>]

"Mark McDougall" <markm@vl.com.au> wrote in message 
news:44ceaf68$0$1466$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> Bryan Parkoff wrote:
>
>>     It is only a question why Deep Red appears in the left of this pixel.
>
> This goes back to my earlier post.
>
> I believe artifacting like this occurs because the phase change is
> limited to +/- 90 degrees. So you can't get from one side of the colour
> wheel to the other (180 deg shift) in a single pixel - it takes two
> pixels to get there. Hence the colour of the artifact is half-way
> between the previous pixel and the next on the colour wheel. In effect
> its colour is totally dependent on the pixels either side of it.

Mark,

    Thanks again.  Do you realize that there is 427 pixels per horizontial 
line of NTSC?  I have no idea where number "427" comes from when I read on 
the website.  Apple II can only display 140 pixels per horizontial line in 
color on all LGR, HGR, and DHGR while 560 pixels per horizontial line in 
monochrome.
    We can't call 560 pixels in color because we have to follow 3.58 MHz 
color reference.  Pixel is defined a group of 4 pulses of 14MHz, but we can 
call four sub-pixels per one whole pixel out of 140 pixels.

Bryan Parkoff