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© 2002 Hewlett-Packard Company
| | This section describes the model used for color
management in the Remote Proofing software. It
assumes some understanding of color management.
In general, to implement a proofing workflow, two color
transformations have to be performed:
- Input transformation: first the input data, possibly in
different color spaces, has to be transformed to the
color space of the final output device: that is, the
device, such an offset press or a digital press, with
which the final material will be produced.
See Input color transformations.
- Proofing transformation: then the graphical content
has to be transformed from the final output device's
color space to the color space of the Designjet 10ps,
20ps, or 50ps to ensure an accurate emulation of
the final result on the Designjet printer.
See Proofing color transformations.
See also:
 | |  | | Input color transformations | | | | |
In general, the input graphical content can be
described either in a device-dependent color space
(DeviceCMYK, DeviceRGB or DeviceGray in PDF
terminology) or a device-independent color space (such
as CIELab, CalRGB, or CalGray).
For device-dependent color spaces the following
transformations are performed:
- DeviceCMYK or DeviceGray: these are supposed to
be in the final output device’s color space, so no
transformation is performed.
- DeviceRGB: the graphical content is transformed
using your chosen RGB input profile and the final
output device’s color profile.
Device-independent color spaces are transformed to the
final output device's color space using the final output
device’s color profile.
In any case, when a transformation is performed, a
rendering intent has to be used. You can select the
rendering intent to be used for all the input
transformations. This rendering intent is used if there is
no rendering intent specified in the input file. Rendering
intent can be specified in an object proof file (see page
14). |
 | |  |
 | |  | | Proofing color transformations | | | | |
Once the graphic contents are in the final output
device’s color space, they have to be transformed to the
Designjet’s color space. This is done using the final
output device’s color profile and the Designjet’s color
profile. The latter is automatically selected depending
on the media type and print quality settings.
In this transformation, a rendering intent has to be used.
For proofing, the only color intents that make sense are
'Absolute Colorimetric' (emulate the final printing
substrate white) or 'Relative Colorimetric' (do not
emulate the final printing substrate white).
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 | |  | | Spot colors | | | | |
There are two possible uses of spot colors:
- A spot color may be used by the designer to refer to
a specific standard color (such as a PANTONE
color) that will be printed on the final output device
using process inks (CMYK). In this case, the spot
color may not be accurately reproducible in the
process ink color space.
- In other cases, spot colors represent inks (tints) that
will be used in the final printing process.
The Remote Proofing color management model supports
both uses of spot colors, but they are mutually exclusive.
That is, either all the spot colors are treated as different
tints or all of them are treated as if printed with process
inks.
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 | |  | | Color management choices | | | | |
In summary, the choices you can make to control color
management in the Remote Proofing workflow are:
- Final output device ICC profile: this is the CMYK
profile that describes the final output device (offset
press, digital press, etc.). Also known as the
'emulation' or 'reference' profile because it is the
profile of the device that has to be emulated by the
proofer.
- RGB input profile: input profile to be used to
transform RGB input.
- Input rendering intent: rendering intent for input
transformations. Any rendering intent is valid.
- Proofing rendering intent: rendering intent for the
proofing transformation (only two rendering intents
are possible).
- Handling of spot colors: they can be treated as if
printed with process inks or with separate tints.
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