POV-Ray : Newsgroups : povray.advanced-users : Media and Opposite Colors Server Time
30 Jul 2024 14:26:17 EDT (-0400)
  Media and Opposite Colors (Message 11 to 20 of 51)  
<<< Previous 10 Messages Goto Latest 10 Messages Next 10 Messages >>>
From: Nieminen Juha
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 06:17:19
Message: <37f095af@news.povray.org>
Ken <tyl### [at] pacbellnet> wrote:
:>   Since when 1 has been equal to <1,0,0>?

: Read the rest of the thread and the answer shall be revealed to you...

  Sorry for the sarcasm...

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


Post a reply to this message

From: Ken
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 06:21:54
Message: <37F0965D.227ED5C3@pacbell.net>
Nieminen Juha wrote:

> > Read the rest of the thread and the answer shall be revealed to you...
> 
>   Sorry for the sarcasm...

You are forgiven my friend.

-- 
Ken Tyler
1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html


Post a reply to this message

From: Remco de Korte
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 08:03:57
Message: <37F0AEF1.A59057DA@xs4all.nl>
Ken wrote:
> 
> Ron Parker wrote:
> 
> > Cyan is the opposite of red.
> 
> Cyan = opposite of red = ok fine by me.
> 
> Thank you for your assistance gentlemen.
> 
> --
> Ken Tyler
> 1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html

That depends. In rgb-calculations cyan is the opposite of red, if for instance
you were using another hightech multimedia-tool like for instance fingerpaint
you'd have green as the opposite of red.
This is part of a list that seems rather inconsistent in rgb-vectors:
red    <-> green   <1,0,0> <-> <0,1,0>
blue   <-> orange  <0,0,1> <-> <1,.5,0>
yellow <-> purple  <1,1,0> <-> <1,0,1>

And even then this is just an arbitrary definition of these colors (is purple
really <1,0,1> or perhaps <.5,0,1>?).

There's no cyan here, nor fuchsia or whatever.
Also with fingerpaint adding more paint doesn't make the color brighter.

This gives you the impression that this way of working with colours is a bit
retarded, but still, that's how it was done for centuries? 
Of course rgb is based on a more scientific interpretation of the behaviour of
light. Fortunately art (?) needn't be dictated by science.

Just my 2 eurocents...

Remco


Post a reply to this message

From: Margus Ramst
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 08:11:21
Message: <37F0B044.F7DC4429@peak.edu.ee>
Ron Parker wrote:
> >so -
> >
> >rgb<1,1,1> - rgb<1,0,0> = rgb <0,1,1> = opposite color ?
> 
> Exactly.
> 
> Cyan is the opposite of red.

The only problem being when the original colour is not full intensity, i.e.
something like rgb <.5,0,0>

rgb<1,1,1> - rgb<.5,0,0> = rgb<.5,1,1>

which is of course spectrally correct, but much brighter than the original.

I simply use my HSL macros (I've all but abandoned RGB)
This is what I do:

hsl(OriginalHue-0.5, S, L) = hsl(OppositeHue, S, L)

If the original hue is <0.5 add 0.5 instead of subtracting. The brightness of
the colour remains the same, which is especially important in media.

Margus


Post a reply to this message

From: Nieminen Juha
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 09:18:59
Message: <37f0c043@news.povray.org>
When we talk about lights, the colors are additive, while when we are
talking about paint, the colors are substractive.
  We should know which color system we are using before we can tell the
correct answer.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


Post a reply to this message

From: Nieminen Juha
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 09:21:18
Message: <37f0c0ce@news.povray.org>
Yes, the answer depends on whether we want the negative color (for
example, the negative color of white is black and vice-versa) or the
opposite hue (where the opposite of black is still black) where we have
to play with the hue instead of the rgb values.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


Post a reply to this message

From: PoD
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 11:15:09
Message: <37F0DCCA.CFC15FE4@merlin.net.au>
Ken wrote:
> 
> Nieminen Juha wrote:
> >
> > Ken <tyl### [at] pacbellnet> wrote:
> >
> > :> (1 - OriginalColor)    ?
> >
> > : rgb<1,0,0> - rgb<1,0,0> = black.
> >
> >   Since when 1 has been equal to <1,0,0>?
> 
> Read the rest of the thread and the answer shall be revealed to you...
> 
> --
> Ken Tyler
> 1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html

But since when is 1 = <1,0,0> ?


Post a reply to this message

From: Ken
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 11:26:52
Message: <37F0DDD9.14012AAC@pacbell.net>
PoD wrote:

> But since when is 1 = <1,0,0> ?

All right people. I was wrong and I was hasty in my reply to TonyB.
I admit that rgb 1 = <1,1,1>. Is everybody happy now ?

-- 
Ken Tyler
1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html


Post a reply to this message

From: Ron Parker
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 11:47:41
Message: <37f0e31d@news.povray.org>
On Tue, 28 Sep 1999 08:25:13 -0700, Ken wrote:
>
>
>PoD wrote:
>
>> But since when is 1 = <1,0,0> ?
>
>All right people. I was wrong and I was hasty in my reply to TonyB.
>I admit that rgb 1 = <1,1,1>. Is everybody happy now ?

No, but if you send me money I'll be happier. :)


Post a reply to this message

From: Peter Popov
Subject: Re: Media and Opposite Colors
Date: 28 Sep 1999 23:26:50
Message: <D8zwN5UE8CenUeheI7006PWZ9vQ=@4ax.com>
On Tue, 28 Sep 1999 14:05:05 +0200, Remco de Korte
<rem### [at] xs4allnl> wrote:


>That depends. In rgb-calculations cyan is the opposite of red, if for instance
>you were using another hightech multimedia-tool like for instance fingerpaint
>you'd have green as the opposite of red.

I'm not sure but I think you are talking about the CMY(K) color model
which is a subtractive one as opposed to RGB which is additive.


Peter Popov
ICQ: 15002700


Post a reply to this message

<<< Previous 10 Messages Goto Latest 10 Messages Next 10 Messages >>>

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.