Re: [stella] VGA vs. NTSC

Subject: Re: [stella] VGA vs. NTSC
From: Greg Troutman <mor@xxxxxxx>
Date: Fri, 05 Sep 1997 10:08:32 -0700
Glenn Saunders wrote:

> NTSC color tends to be "compressed" compared to RGB.  Blacks are greyer,
> colors more saturated, whites are whiter.  NTSC can't even faithfully
> represent 24-bit color because of this.  Any brightness over 211 in the R,
> G, or B or so will bloom out your monitor.
> 
> Any "antialiasing" is just blurring due to TV's having such poor dot
> pitch and the artefacts of pumping the signal through RF which degrades
> the signal signifiantly.  I'm not so fond of this.

Here's a related thing I'm wondering about.  Certain colors appear
shifted on both the emulator and television.  That is, objects drawn at
the exact same horizontal location will seem to be not quite as wide or
perhaps drawn a teeny bit further to the right as you change only the
color (darker, or lower luminosity seems to move further right).  Since
it happens on both TV and the emulator I guess there's something about
the eye and the visible light spectrum that might be involved here (an
optical illusion type thing).  The effect is much more pronounced on
television though.  So much so that when simple color striping is used,
objects other than plain bars can become too distorted to look good,
without experimenting to select "better" colors to avoid this problem. 
One additional thing I've noticed is that this effect is most pronounced
when colors are drawn on top of a black background, and can be somewhat
cured when a brighter colored background is used.  I'm not sure where
I'm going with this...  In experimenting with different colors to try
and understand this, I've stumbled upon at least one combination of a
background color with a color-cycle-striped, player-graphic that looks
completely awesome.  It produces a nice depth illusion, almost as if the
object were embossed on the screen.  The illusion works on both
television and the emulator, but not with the same color-scheme.  It
looks "right" on television with one luminosity setting, but the
emulator needs the background cranked up a couple more notches in
luminosity to achieve the same effect.  Perhaps over time, we will put
an option in our games to select "emulator mode" so we can change the
colors to look better???

--
mor@xxxxxxx
http://www.crl.com/~mor/

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