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There was a discussion in one of the groups on this server not long ago about
converting rgb to grayscale values. I've been looking for that thread but can't
find it. Some formulas were mentioned and I'd like to try those again.
Houdoe!
Remco
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I'm also looking for a thread that I can't find: it was one where somebody
posted formulas for a conical pattern plus some other stuff.
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Would that be using different "weights" for different colors, i.e., a picture using
only solid rgb would have different gray levels? A very easy way to do it, of
course, would just be to average the rgb values, but somehow I don't think that's
what you want. Then there's hue-chroma-value (referred to as
hue-brightness-saturation in most programs), which would make more sense. I don't
know those, but they should be easy formulas to find.
Remco de Korte wrote:
> There was a discussion in one of the groups on this server not long ago about
> converting rgb to grayscale values. I've been looking for that thread but can't
> find it. Some formulas were mentioned and I'd like to try those again.
>
> Houdoe!
>
> Remco
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Remco de Korte wrote:
>
> There was a discussion in one of the groups on this server not long ago about
> converting rgb to grayscale values. I've been looking for that thread but can't
> find it. Some formulas were mentioned and I'd like to try those again.
>
> Houdoe!
>
> Remco
Subject: Rendering in B&W?
Date: Thu, 11 Mar 1999 20:54:19 -0500
From: Kyle <joe### [at] geocities com>
Newsgroups: povray.general
--
Ken Tyler
1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html
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Ken wrote:
> Remco de Korte wrote:
> >
> > There was a discussion in one of the groups on this server not long ago about
> > converting rgb to grayscale values. I've been looking for that thread but can't
> > find it. Some formulas were mentioned and I'd like to try those again.
> >
> > Houdoe!
> >
> > Remco
>
> Subject: Rendering in B&W?
> Date: Thu, 11 Mar 1999 20:54:19 -0500
> From: Kyle <joe### [at] geocitiescom>
> Newsgroups: povray.general
Also:
Subject: Rendering Black and White
Newsgroups: povray.binaries.images
Date: Thu, 05 Aug 1999 07:45:00 -0800
From: David Heys <cel### [at] hotmailcom>
David
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On Wed, 29 Sep 1999 04:14:50 +0200, Remco de Korte
<rem### [at] xs4allnl> wrote:
>There was a discussion in one of the groups on this server not long ago about
>converting rgb to grayscale values. I've been looking for that thread but can't
>find it. Some formulas were mentioned and I'd like to try those again.
>
>Houdoe!
>
>Remco
A rough formula is:
Gray = 0.30*Red + 0.59*Green + 0.11*Blue
It might be 31 for red and 10 for blue but you have the idea.
There is a DOS interrupt that would convert a VGA palette entry from
rgb to grayscale. I think it is int 10,10,0b but I might be wrong (man
was it a long ago!). If you have some info on he ints you might check
it out, this is where I know this formula from.
Peter Popov
ICQ: 15002700
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> Date: Thu, 11 Mar 1999 20:54:19 -0500
YYEEEEYYYY!!!
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Peter Popov wrote:
>
> A rough formula is:
>
> Gray = 0.30*Red + 0.59*Green + 0.11*Blue
>
> It might be 31 for red and 10 for blue but you have the idea.
>
> There is a DOS interrupt that would convert a VGA palette entry from
> rgb to grayscale. I think it is int 10,10,0b but I might be wrong (man
> was it a long ago!). If you have some info on he ints you might check
> it out, this is where I know this formula from.
>
> Peter Popov
> ICQ: 15002700
Thanks, for all the replies.
The thread in March wasn't the one because I remembered it as being within the
last three months so it was probably that from August, but what Peter has here
should keep me happy for a while.
BTW: I'm truly very sorry that I can't show you what this is all about, since
it's a project I'm working on that is now close to 200Mb. Just let me say that
it is great fun and nearly 100% POV-Ray on the outside 8)
Remco
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Peter Popov wrote in message ...
>On Wed, 29 Sep 1999 04:14:50 +0200, Remco de Korte
><rem### [at] xs4allnl> wrote:
>
>>There was a discussion in one of the groups on this server not long ago
about
>>converting rgb to grayscale values. I've been looking for that thread but
can't
>>find it. Some formulas were mentioned and I'd like to try those again.
>>
>>Houdoe!
>>
>>Remco
>
>A rough formula is:
>
>Gray = 0.30*Red + 0.59*Green + 0.11*Blue
>
>It might be 31 for red and 10 for blue but you have the idea.
>
>There is a DOS interrupt that would convert a VGA palette entry from
>rgb to grayscale. I think it is int 10,10,0b but I might be wrong (man
>was it a long ago!). If you have some info on he ints you might check
>it out, this is where I know this formula from.
The interrupt is INT 10 with AX = 101B. The list I have doesn't have any
more information than that.
Mark
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On Thu, 30 Sep 1999 00:29:58 -0400, "Mark Wagner"
<mar### [at] gtenet> wrote:
>The interrupt is INT 10 with AX = 101B. The list I have doesn't have any
>more information than that.
>
>Mark
I just checked the Norton Guide to see if my numbers were correct (I
had some doubts they were 0.31, 0.59, 0.10 instead but they are the
way I reviously posted them) and I saw that indeed the subfunction was
1B. Well, I haven't played with the VGA since I got windoze 95 (4
years now?)
Anyway, enough OT. I just wanted to say that I checked with my sources
and confirm the formula 0.30*R + 0.59*G + 0.11*B.
Peter Popov
ICQ: 15002700
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