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(more info)
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Click on the following links to go to the thumbnails below,
then click on a thumbnail to see a full size image.
Jump to
features,
detailed specs
Windows XP
Mac OS X
The main screen, with the Space #2 list box opened, and Custom
space highlighted. The space selection list is identical for Space #1. The larger green
color patch corresponds to Space #1, and the smaller pinkish color patch to
Space #2. The color patches are converted from the selected RGB space to the
default viewing environment (sRGB for Windows, Apple RGB for Mac
OS 8 and 9, Apple RGB or sRGB for Mac OS X). For the Windows
screen shown above, the Space #1 color patch is converted from Adobe (1998)
to
sRGB; the Space #2 color patch is converted from sRGB to sRGB
(i.e. there is no translation). For the Mac screen shown above, the Space #1
color patch is converted from Adobe (1998) to
Apple RGB; the Space #2 color patch is converted from Apple RGB to
Apple RGB (i.e. there is no translation).
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Density tools
Metamerism tools
RAL tool
Graph tools
Graph tools (saved image)
ISO 3664+ (Illumination analysis) ISO 3664+
(Monitor analysis) ISO 12646
target
Click on a thumbnail for a full size image and descriptive
text. To have a look at all Spectral tools, first click on the "Density tools"
thumbnail, then select "Next screen" in the full view page that opens. top
Compare Mac (Apple RGB) to Windows (sRGB)
The same RGB coordinates entered in Apple RGB (Mac default, on the
LEFT side) and sRGB (Windows default, on the RIGHT side). The large,
lighter colored, color patch shows what the color looks like on Macintosh
display (even if this is a Windows XP screen; i.e. the color is properly
translated from Apple RGB to sRGB
for display purposes). You can see on the chromaticity diagram that the
same RGB coordinates correspond to two different colors (i.e. they have
different "xy" coordinates). In essence, the darker
sRGB color patch shows how a color generated on a Mac will look on a
Windows PC if it is not properly translated to the sRGB environment. The
CIE94 color difference is 5,51, a very noticeable difference. The difference
is mostly intensity (DeltaL* = -5,25), followed by chroma (i.e. saturation;
DeltaC* = 3,91), and some hue difference (DeltaH* = 2,21).
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A color conversion from Space #2 to Space #1. The spaces have
different primaries as well as different illuminants; still, BabelColor CT&A can
determine the exact match. Notice that the CMC(2:1) D50 color difference
is zero; since the illuminant is different, both spaces coordinates are
converted to D50 in order to obtain a valid color difference value. In the
chromaticity diagram, you will notice that the "xy" coordinates are
different but this is expected since the illuminants are also different.
BabelColor CT&A determines the equivalent color when viewed by the other space
illuminant. top
L*a*b* input in Adobe (1998), converted to sRGB. In
this example, L*a*b* values had been determined relative to illuminant D65, but
D50 values could also be used as input by first checking the "L*a*b* / L*u*v*
in D50" radio button under the L*a*b* display (L*u*v* input is also
possible). The color is outside of the sRGB gamut and clipping has
occurred for the red coordinate; a red exclamation point (
! ) appears over the corresponding display box of Space #2. The
clipping error is 7,07 CIE94; the error can also be evaluated using the
other formulas shown in the opened list box. There is another exclamation point
(
! ) in the larger color patch, indicating that
the Space #1 color cannot be exactly represented in a Windows sRGB
display (the red coordinate is clipped). Also show in Space #2 is the Munsell
HVC equivalent of the converted color (2,2G 5,9/10,5).
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Munsell color chip 7,5G 7/6 (from
the Munsell Color Deck) being converted to sRGB.
We see that the selected chip, located in the middle of the list on the LEFT
side, is well within the sRGB gamut, with a zero DeltaE*uv error; the
matching sRGB value is (108, 191, 160). To navigate within the
Munsell Color Deck, we have used the List mode, where the color patches are
presented in the order they are stored in the database. We could have also used
the other deck navigating mode, the L*C*h* pad, shown in the next screenshot.
Converting TO Munsell is available for any RGB color, as can be seen in the
HVC data fields on the screenshot's right side; this conversion is
computed with a precision of one decimal place.
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R'G'B' input in Adobe (1998) converted to the
FED-STD-595B Color Deck (we can also convert FROM FED-STD-595B). We see that there is not an exact match, and the
closest chip is #14255, as represented by the square patch in the center of the
L*C*h* pad, with a 2,40 CIE94 error. The patches around the center one
show the NEXT best matches in terms of closeness in saturation (+/- sat., i.e.
chroma), luminosity (+/- lum., i.e. lightness), and hue;
their IDs can be obtained by resting the mouse cursor over the patch until a
popup tag appears (as shown above for the + sat. patch).
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Additional graphical data can be superimposed on the chromaticity diagram.
The above image shows the position of the GretagMacbeth ColorChecker chart
patches as computed for illuminant D65. Similar data for illuminants C and D50
can be shown as well as the gamut of SWOP coated.
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A custom RGB space can be defined by specifying the illuminant
coordinates, the red, green and blue primaries, and the gamma function. A
D-series or blackbody illuminant can be defined simply by entering
the source temperature, in kelvin. Gamma can be defined by a single
parameter or a two segment function with a slope for the linear portion, a
transition, an offset, and a gamma value. You can also export all the custom
data as well as the XYZ-to-RGB and RGB-to-XYZ matrices
coefficients to a spreadsheet. top
By consulting the menu-selectable data tables, the user can obtain
information on the constants and parameters used internally by BabelColor CT&A to
compute the displayed data. The table shown above contains the space's
primaries, its illuminant, and the gamma parameters. Other
tables are available for the illuminants' coordinates, the RGB to XYZ
and XYZ to RGB conversion matrices, and for the Bradford matrices
used to convert XYZ coordinates between different illuminants (i.e. chromatic
adaptation). top
Windows XP
Mac OS X
A complete help manual is provided. It contains a detailed description of the
features and the interface, a thorough theoretical presentation, with all the
equations, of the various conversion processes within BabelColor CT&A, and tutorials
with an emphasis on practical uses. The Windows manual, the thumbnail on the
left, is built in the HTML Help format; it is fully indexed and
searchable. The Mac manual, the thumbnail on the right, is an hyper-linked
PDF file; the file has an index, and is searchable. Both manuals can be
printed. top |
BabelColor