Hello all!
I don't have time for the following stuff, but hopefully some of you can
cooperate with this guy. I'm not sure whether his point regarding the
methods used for extracting the RGB values is valid. In order to measure
the RGB values, you have to extract the information from the chroma
signal, and every method doing so may be inaccurate.
See also my luminance level measurements at
<URL:http://www.funet.fi/pub/cbm/documents/chipdata/656x-luminances.txt>
if you are interested in this topic. Also, Pasi Ojala, George Taylor (are
you on this list?) and another NTSC guy made some color measurements at
about the same time I measured the luminances at the end of 1996 (gosh,
the time flies: I thought it would've been at the end of 1997).
Marko
---------- Forwarded message ----------
Date: Sun, 24 Jan 1999 21:14:16 +0100
From: Philip Timmermann <MOD@STARDATE.WESTFALEN.DE>
To: marko.makela@hut.fi
Subject: .oO C=64 colors Oo.
Hola...
I already sent the following mail a few hours ago, but my provider
replied me a message, that your account doesn't exist...
I'm trying again now... hope you don't get this several times... 8-/
-///-CUT-HERE---------------------------------------------------------
Hola...
First of all, please excuse my really bad english - it's not my native
language, but i hope all is 'understandable'... ;)
I read your Name in various Articles about the VIC-II and therefor
hope, that you are the right man in the right place... ;-)
Since quite some time, I'm studying the color-palette of my C=64 and
searched a 24bit-equal (RGB) in the first place, in order to work with
it on my Amiga...
After collecting and studying many Palettes, i recognized that no one
really matched the original C=64 colors...
No palette for example 'took care' of the fact that every color has a
'partner-color' with exactly the same brightness (at least on my
C=64_c). This can be quite easily verified, by removing the color
with the slider of the C=64-Monitor. Someone informed me via e-Mail,
that the C=64_a differs in color-behaviour and brightness within the
palette... Theoretically this can also be verified, by removing the
color on the monitor...
.---+-------------+-----.
Here is a list, in which you can see, how !<b>! 64a ! 64c !
the colors are sorted by brightness. "<b>" +---+-------------+-----+
is the brightness, where 0 is the darkest ! 0 ! 0 ! 0 !
and 8 is the brightest. The numbers on the ! 1 ! ! 6,9 !
right are Hex-Codes of the colors in the ! 2 ! 2,6,9,B ! 2,B !
C=64-palette. The numbers of the C=64_a ! 3 ! ! 4,8 !
are by a guy from Usenet... ! 4 ! 4,5,8,A,C,E ! C,E !
! 5 ! ! 5,A !
! 6 ! 3,7,D,F ! 3,F !
Following here, is a list of the ! 7 ! ! 7,D !
color-names which belong to the Hex-codes ! 8 ! 1 ! 1 !
of the palette... +---+-------------+-----+
.---+------------+---+------------+---+------------+---+-------------.
! # ! color-name ! # ! color-name ! # ! color-name ! # ! color-name !
+---+------------+---+------------+---+------------+---+-------------+
! 0 ! Black ! 4 ! Purple ! 8 ! Orange ! C ! Medium-Grey !
! 1 ! White ! 5 ! Green ! 9 ! Brown ! D ! Light-Green !
! 2 ! Red ! 6 ! Blue ! A ! Light-Red ! E ! Light-Blue !
! 3 ! Cyan ! 7 ! Yellow ! B ! Dark-Grey ! F ! Light-Grey !
+---+------------+---+------------+---+------------+---+-------------+
Info: It's not 'getting brighter' in a linear way... (C64_c) The
'Jump' between the color-pair C-E and 5-A is for example shorter, than
the 'Jump' between the other color-pairs, and the 'Jump' between 0 and
the color-pair 6-9 or between 1 and the color-pair 7-D is bigger than
the other 'Jumps'...
Additionally the Greys can _not_ (!) be 'build' by simple logic:
Dark-Grey (64/64/64), Medium-Grey (127/127/127), Light-Grey
(191/191/191)... That's _not_ the way it works... Dark- and
Light-Grey are much 'closer' to Medium-Grey, than to BLK or WHT...
"Removing the color with mon-slider" can be precisely emulated with
lots of Image-Processor-Prgs. The program PPaint (Amiga) by Cloanto
for example features a color-intensity-slider, with which you can
slowly fade out the color. I tested, if this digital method differs
from the analog method of the monitor. I connected an Amiga to the
same monitor like the C=64 and displayed a very colorful picture with
PPaint. Then I moved the color-intensity-slider of PPaint and the
change was of course very visible. Then I removed the color with the
slider of the monitor and again moved the color-intensity-slider of
ppaint. No change was visible at all, so i think that both methods
deliver the very same results.
So you can easily verify if a RGB-color-clone of the palette features
the same color-brightness of the original.
No RGB-clone I found was sucessful in this test. Most people just
made 'Full-Range'-palettes (Red (FF/00/00), Blu (00/00/FF), etc.).
Some people tried to match the color by placing a PeeCee with a
MultiScan-Mon next to the C=64 with C=64-mon and do it 'by hand'.
These palettes differ much from the original, because it heavily
depends on Color-, Contrast- and Brightness-settings of the C=64-mon.
Additionally there are palettes from people, who just connected their
C=64 to a TV-card or a FrameGrabber in order to digitize the color.
Sadly every TV-card and FrameGrabber seems to have a different
color-behaviour, so all these palettes differ very much from eachother
and aren't sucessful in the PPaint-test...
Sooooo, there must be a possibility to get the _exact_ and _precise_
24 Bit RGB-Values... Theoretically it must be possible to find the
color-values which the VIC-II really produces...
Sadly I'm no hardware-specialist at all, but you seem to know a lot
about the VIC-II, and even if you don't have the needed hardware you
perhaps know some friends who have!? I guess you are one of the last
people who can solve one of the last misterys of the C=64... 8^)
I would like to know what you think about all this and if you can
think of a method which could help to find the right values...
Thanks for your time... C= forever... ;-) can't wait to read your
reply! Please let me know, if this mail reached you...
.oO Philip 'Pepto' Timmermann Oo.
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