1
This directory contains several alternative rgb databases:
3
old-rgb.txt the version that was shipped in previous
4
releases; this was originally "tuned" for
5
the Digital VT240 series terminals.
7
raveling.txt lots of new colors, tuned by Paul Raveling
8
at ISI for the HP monitor; see below.
10
thomas.txt a version of the older database that was
11
tuned by John Thomas at Tektronix to match
12
a box of Crayola crayons; see below.
15
Notes from Paul Raveling:
17
1. Many colors have been tuned for an HP monitor -- mine,
18
to be exact. Some of the old values were obnoxious enough
19
to bring complaints from users (like "That's Wheat???!!!");
20
so far early user reports on the new RGB database are favorable.
22
2. File rgb.txt was reorganized into 3 sections:
24
a) Light and off-white colors, copied from several Sinclair
25
Paints color samples. The intent for adding these is
26
to provide a better choice for light-colored window
29
BTW, I wanted to find ANSI standard colors, but ANSI
30
happily gobbled my $16 without sending the specification
31
I ordered, Then they ignored my followup letter.
32
Nuts to ANSI & "ANSI standards".
34
b) Special colors such as black, white, and favorite
37
c) A spectrum of colors, arranged to transition gradually
38
between nearby colors, running from generally blue
39
colors through green and ending with generally red colors.
40
This includes all colors from the old X11R3 database,
41
but they're no longer in (mostly) alphabetic order.
43
d) The gray scale from the original X11R3 database.
46
Within the "spectrum of colors" section there are clusters
47
of colors, each consisting of:
49
1. One or more Specially named colors. If more than one
50
is present, all are related by lying on a common line
51
running from RGB = (0 0 0) [pure black] to a single
52
point on the surface of the RGB color cube.
54
2. Four colors at particular points on the same line in
55
RGB space. Their names end in "1", "2", "3", and "4",
56
with "color1" being at the surface of the color cube
57
and the others at increasing distances approaching black.
58
Distance of these color points from black is approximately
59
logarithmic. This attempts a rough fit to human
60
perception's sensitivity to intensity.
62
Here's an example of one of these clusters:
65
139 69 19 saddle brown
72
Note that the "original" colors, in this case chocolate
73
and saddle brown, don't always match the scaled points.
76
Does anyone think these changes are a good idea? Crummy idea?
77
Do you have other favorite colors? Can anyone do better at
78
matching some tough colors? Some colors, especially reddish
79
ones, were VERY hard to reproduce, & I'd welcome contributions
80
from other HP users who can get a better match.
84
Notes from John Thomas:
86
Advised by our human factors folks that "standard" named colors exist, but
87
only for well-controlled color coordinate systems (like CIE, but not for RGB),
88
I sat down one evening with the handiest standard of subjective color names,
89
a box of 72 Crayola crayons. (Believe it or not, over 50% of the colors from
90
rgb.txt were represented.)
92
Using an X-client implementation of the TekColor model, I created the following
93
list of named colors. Appearance on your monitor may vary because of brand,
94
age, and video drive circuitry, but I think you will find it a better match
95
for the average monitor, than the original rgb.txt file from MIT.
added
removed
rgb/others/README
