Nikon Scan 4 User manual

78
TOP
Preferences—Nikon Color Management
Nikon Color Management
Nikon Color Management
Keeping Colors True
Keeping Colors True
The Nikon Color Management System, or Nikon CMS, en-
sures that image data from Nikon scanners are reproduced
consistently and accurately on monitors or printers. With this
powerful tool, colors can be manipulated in a calibrated RGB
color model before the data are passed to the host applica-
tion. Profiles detailing the color characteristics of the chosen
color model and the output device (monitor or printer) en-
sure that colors will be reproduced accurately in almost any
operating environment.
Nikon CMS involves two categories of preferences, one
(“Gamma”) for use when Nikon CMS is off and the other
(“Color Management”) for use when Nikon CMS is on.
“Gamma” specifies how data from the scanner will be mod-
ified for display on the monitor. Because monitor profiles
can not be used when Nikon CMS is off, this adjustment
must be made manually. “Color Management” is used to
turn Nikon CMS on and off and select the profiles for use
with the monitor and with the CMYK and calibrated RGB
color models when Nikon CMS is on.
Turning Nikon CMS Off
Turning Nikon CMS Off
In general, much better results can be achieved with Nikon CMS on. It
may however be necessary to turn color management off to:
• Speed processing
If the computer has a slow CPU, the processing required for color
management may result in longer scan times. Try turning color man-
agement off for reduced scan times.
• Edit data from the scanner directly
Advanced users may want to turn Nikon CMS off to edit uncalibrated
RGB data from the scanner.
CMYK
CMYK
Images can not be scanned in CMYK. If CMYK data are required, con-
vert images to CMYK before saving them to disk. Note that images
can only be saved in CMYK if Nikon CMS is on (Nikon CMS is on by
default).

79
TOP
Preferences—Nikon Color Management
How Nikon CMS Works
Color-Space Profiles
Separate profiles are available for the RGB and CMYK color
models. Nikon Scan comes with a selection of profiles for
the RGB color model, while CMYK profiles for color printers
are usually provided by the manufacturer. Color-space pro-
files are used when editing images in the scan window and
when making the final scan.
Monitor Profiles
Monitor profiles are usually provided by the manufacturer,
although profiles for some common monitor types may be
included with the computer operating system. Monitor
profiles apply when images are displayed on a monitor, for
example when an image is displayed in the preview area or
an image window.
Creating Monitor Profiles
Creating Monitor Profiles
If desired, Adobe Photoshop can be used to create a monitor profile for
a specific environment. This profile can then be used in Nikon Scan.
For information on creating monitor profiles, see the documentation
provided with Adobe Photoshop. This option is not available in Adobe
Photoshop LE.
When image data are passed from an input device, such as
a scanner, to an output device, such as a monitor or printer,
color management ensures that the image displayed on the
output device “looks the same” as the original. To accom-
plish this task, the color management system must have
information about the color characteristics of both the input
and output devices, as well as the color space used for edit-
ing. The files containing this information are called “ICC pro-
files.” Nikon Scan uses the following three types of profile:
Input Profiles
Input profiles provide information on the input device, i.e.,
the Nikon scanner. Fixed profiles detailing the color char-
acteristics of supported Nikon scanners are provided with
Nikon Scan. An input profile is selected automatically based
on the model of scanner used and the type of media (pos-
itive or negative) being scanned.

80
TOP
Preferences—Nikon Color Management
Scan
Scan
Preview
The Scanning Process
The illustration below shows the role Nikon CMS plays in
the scanning process. CMS profiles are shown in blue, user
operations in red.
When Nikon CMS is on, uncalibrated RGB image data from
the scanner are converted to grayscale or calibrated RGB,
depending on the color model selected in the scan window.
RGB data are processed according to the profile selected for
the calibrated RGB color space. These data are stored in
memory so that the color model can be changed without
performing another preview. Any changes made using the
color enhancement and Unsharp Mask tools also apply to
these data. When the image is displayed in the preview win-
dow, the monitor profile is used to ensure that the preview
image is as true as possible to the data in memory.
When the Scan button is clicked to perform the final scan,
the scan data are processed according to the selected color-
space profile and any changes that were made using the
color enhancement and Unsharp Mask tools in the scan
window. The data are then transferred to the host appli-
cation. Where possible, the color-space profile is transferred
to the host application together with the image data. The
TWAIN interface used in Windows, however, does not allow
profiles to be passed to another application, with the result
that under Windows the profile is only transferred to the
host when Nikon Scan is used as a “stand-alone” application
(note that profile information is lost when the image is saved
in a format such as BMP that does not allow the profile to
be recorded). When images are displayed in image windows
in Nikon Scan, the monitor profile ensures that the image on
the screen reflects the original as closely as possible.
Before preview
Film type selection
Color model and profile
selection
Preview
Color-space
profile
Image processing
Changes to color
model or color-
space profile
New color-
space profile
Curves
Color Balance
LCH Editor
Unsharp Mask
Scanner
input profile
Monitor
profile
Monitor
profile
Scanner Extras
Digital ICE4Advanced
Scan Image Enhancer
Analog Gain
Processed tab
Natural tab
Host application

81
TOP
Preferences—Nikon Color Management
Scan
Scan
PreviewBefore preview
Gamma adjustment
Preview
Image processing
Curves
Color Balance
Preview
gamma
Scanner Extras
Digital ICE4Advanced
Scan Image Enhancer
Analog Gain
Processed tab
Natural tab
Host application
Main
scan
gamma
Preview
gamma
Scanning with Nikon CMS Off
If Use Nikon Color Management System is not selected in
the “Color Management” category, profiles can not be used
to ensure that the data from the scanner are reproduced ac-
curately when passed to another application or displayed in
the monitor. Because the color profiles required for a cali-
brated RGB color space are not available when Nikon CMS is
off, images can only be scanned as uncalibrated RGB or gray-
scale. Similarly, the absence of a monitor profile means that
gamma adjustment must be used to correct the image for
display on the monitor or for editing in another application.
These adjustments to gamma are made in the “Gamma”
category of the “Preferences” dialog.
The illustration below shows how scanning proceeds when
Nikon CMS is off. The image shown in the preview window
is adjusted for display in the monitor according to the value
chosen for preview gamma in the “Gamma” category. When
the Scan button is clicked, the main scan gamma and any
changes to curves and color balance are passed to the scan-
ner, where they are applied to scan data before the image is
transferred to the host application (if Nikon Scan is used as
a “stand-alone” application, the value for preview gamma
is passed to the scanner instead of main scan gamma). The
LCH Editor and Unsharp Mask tools can not be used when
Nikon CMS is off.

82
TOP
Preferences—Nikon Color Management
Gamma
When the Use Nikon Color Management System option
in the “Color Management” category ( 84) is off, the con-
trols in the “Gamma” category are used to adjust data from
the scanner so that they display correctly when previewed on
the monitor or opened in another application.
Preview gamma
Preview gamma applies to the image displayed in the pre-
view area of the scan window. In general, preview gamma
is solely for display in the preview area and does not apply
to the image data that are passed to the host application
when the Scan button is clicked. There are two exceptions
to this rule, however. The first is when Nikon Scan is used as
a “stand-alone” application, the second when Use preview
gamma is selected as the main scan gamma option. In
these cases preview gamma is applied to image data passed
to the host application.
Preview gamma defaults to a value of 1.8 on the Macintosh,
2.2 on Windows computers. To choose a setting suited to
the current monitor, adjust the value so that the patterns of
gray lines and dots above the slider match in density. Gam-
ma can be set by entering a value directly into the text box or
by moving the slider. When making this adjustment, set the
resolution on the monitor to a low value such as 640 ×480
and sit as far away from the monitor as possible. To restore
the default setting for your platform, click Reset.

83
TOP
Preferences—Nikon Color Management
Main scan gamma
Main scan gamma options are only
visible when Nikon Scan is being
used as a TWAIN source or acquire
plug-in for another program (when
Nikon Scan is used as a “stand-
alone” application, preview gamma automatically applies
both to the preview image and to the final scan). Image data
passed to the host application are modified according to the
option chosen here. Three options are available:
Use preview gamma
The gamma value chosen for preview gamma is applied be-
fore the data are passed to the host application. Use this
setting when the host application does not support inde-
pendent gamma settings and you want the final image to be
modified for display on your monitor.
Use application gamma
In some environments, a value for gamma can be chosen
in the host application and passed to the Nikon Scan plug-
in. When Use application gamma is selected, this value is
applied to the main scan data before they are passed to the
host application.
Two conditions must be fulfilled if this option is to be effec-
tive. First, the interface between the application and Nikon
Scan must allow the gamma value to be passed to the Nikon
Scan plug-in. The TWAIN interface used under Windows
does not, however, allow the gamma value to be passed to
the TWAIN source (i.e., to Nikon Scan). Consequently, in the
Windows version of Nikon Scan a default value of 2.2 is used
for main scan gamma whenever Use application gamma
is selected. Second, the application must support gamma
transfer. If Use application gamma is selected with a
Macintosh application that does not support this feature,
Macintosh system gamma (1.8) will be used.
Use custom gamma
When this option is selected, a value for main scan gamma
can be entered in the text box.

84
TOP
Preferences—Nikon Color Management
Color Management
The profiles used by the Nikon Color Management System
are specified in the “Color Management” category.
Use Nikon Color Management System
This option turns the Nikon Color Management System on
and off. Changes to this setting only take effect after Nikon
Scan has been quit and restarted.
When Nikon CMS Is On…
…images are processed to ensure consistent color repro-
duction, as described in “How Nikon CMS Works” ( 79).
Because color management profiles typically contain their
own settings for gamma, the controls in the Gamma tab are
dimmed and inactive.
When Nikon CMS Is Off…
…monitor and color-space profiles are not used, and the
controls in the Color Management tab are dimmed and in-
active. The only tool available for ensuring that colors from
the scanner will be displayed accurately on the monitor is
the “Gamma” category ( 82). The only adjustments made
to the image before it is passed to the host application are
gamma adjustment and changes to curves and color balance
made in the scan window.

85
TOP
Preferences—Nikon Color Management
The “Monitor” Tab
The “Monitor” tab specifies the profile that will be used
when images are displayed on your monitor, either in the
scan window preview area or a Nikon Scan image window.
Monitor profiles contain information about the color and
gamma characteristics of the monitor, allowing images to be
adjusted for more accurate color reproduction.
Use factory default monitor profile (default)
Nikon Scan is supplied with default monitor profiles for use
when no other profile is available (see below). To use the
default profile for your platform, select Use factory default
monitor profile.
Default Windows Monitor Profile (Gamma 2.2)
The default Windows monitor profile (“NkMonitor_Win.icm”)
is identical to the sRGB profile.
Default Macintosh Monitor Profile (Gamma 1.8)
The default Macintosh monitor profile (“NkMonitor_
Mac.icm”) is identical to the profile used for Apple 17˝ moni-
tors with a D50 white point.
Use custom monitor profile
Use this option to select a profile supplied by the company
that manufactured the monitor. When this option is se-
lected, the Choose Custom Profile… button will be active.
Clicking this button displays a standard “open file” dialog;
navigate to the disk and folder containing the manufacturer’s
profile. The path to the selected profile will appear in the
text box below the Use custom monitor profile radio but-
ton.

86
TOP
Preferences—Nikon Color Management
The “RGB” Tab
The “RGB” tab is used to select a color-space profile for the
calibrated RGB color model. The profile used can be selected
from the Color space menu.
Each of the profiles listed may be classified according to its
gamma value and gamut. Gamma is a fundamental char-
acteristic of imaging systems which determines the intensity
of the output signal relative to the input; in human terms,
gamma controls the subjective brightness of images through
alterations to the output level for mid-tones. Windows
and Macintosh systems process video signals differently,
and these differences are reflected in the difference in the
standard gamma values for these platforms. The default
system gamma for Macintosh computers is 1.8, the de facto
standard for Windows systems, 2.2. Nikon CMS includes
eight RGB profiles with a Windows gamma of 2.2 (sRGB,
Bruce RGB, NTSC [1953], Adobe RGB [1988], CIE RGB, Wide
Gamut RGB, compensated Wide Gamut RGB, and Scanner
RGB), and three profiles with a gamma value of 1.8 (Apple
RGB, ColorMatch RGB, and compensated Apple RGB), for
use on the Macintosh. When scanning images, choose a
profile with a gamma value suited to the system on which
the image will be edited.

87
TOP
Preferences—Nikon Color Management
The “CMYK” Tab
The CMYK sheet is used to select a profile for use with the
CMYK color model.
Use factory default CMYK profile (default)
Nikon Scan is supplied with a default CMYK profile (the
SWOP color library) for use when no other profile is avail-
able. This profile is used when Use factory default CMYK
profile is selected.
Use custom profile
Use this option to select a profile supplied by the company
that manufactured your printer. When this option is selected,
the Choose Custom Profile… button will be active. Click-
ing this button displays a standard open-file dialog; navigate
to the disk and folder containing the manufacturer’s profile.
The path to the selected profile will appear in the text box
below the Use custom CMYK profile radio button.
CMYK
CMYK
Images can not be scanned in CMYK. If CMYK data are required, con-
vert images to CMYK before saving them to disk. Note that images
can only be saved in CMYK if Nikon CMS is on (Nikon CMS is on by
default).