spectro/dispread
Summary
Display test patches on a monitor, read the colorimetric value result
with the colorimeter, and create the chart readings file.
Usage
dispread [-options] inoutfile
-v
Verbose mode
-display displayname [X11 only] Choose X11 display name
-d n
Choose the display from the following list (default 1)
-c listno
Set
communication port from the following list (default 1)
-a
Run calibration
-i 92|94|SO
Select
target
instrument
92
=
DTP92, 94 = DTP94, SO = Spectrolino
-y c|l
Display type, c = CRT, l = LCD
-k
file.cal
Apply
display calibration file while reading
-s
Save spectral information (default don't save)
-p ho,vo,ss
Position
test window and scale it
ho,vi: 0.0 = left/top, 0.5 = center, 1.0 = right/bottom etc.
ss: 0.5 = half, 1.0 = normal, 2.0 = double etc.
-n
[X11 only] Don't set override redirect on test
window
-N
Disable auto calibration of instrument
-D
Print debug diagnostics
inoutfile
Base name for input[.ti1]/output[.ti3] file.
Examples
dispread -c1 -i92 mycrt
Comments
This is the utility for exercising a display, in order to measure its
color characteristics. The device test colors are defined by the
outfile.ti1 file, while the resulting device+colorimetric and optional
spectral readings are stored in the outfile.ti3 file. Display
calibration curves can be applied during the measurements, and the
curves included in the resulting .ti3 data file using the -kflag. See dispcal
for information on how to calibrate the display before profiling
it. For best results, you should run this
against a neutral grey desktop background, and avoid having any bright
images or windows on the screen at the time you run it.
The -v flag reports progress information.
When running on a UNIX based system that used the
X11
Windowing
System, dispread
will by default use the $DISPLAY environment variable to determine
which display and screen to read from. This can be overridden by
supplying an X11 display name to the -display
option. Note that if Xinerama is active, you can't select the screen
using $DISPLAY or -display, you have to select it using the -d parameter.
By default the main display will be the location of
the test window. If the system has more than
one display or screen, an alternate display/screen can be selected with
the -d parameter. If you
invoke dispread
so as to display the usage
information (i.e. "dispcal -?" or "dispcal --"), then the discovered
displays/screens will be listed. Multiple displays may not be listed,
if they appear as a single display to the operating system (ie. the
multi-display support is hidden in the video card driver). On UNIX
based system that used the X11
Windowing
System, the -d parameter will
override the screen specified by the $DISPLAY or -display parameter.
The instrument is assumed to communicate through a
USB or serial communication port, and the port can be selected with the
-c
option,
if the instrument is not connected to the first port. If you invoke dispread
so as to display the usage
information (i.e. "dispread -?" or "dispread --"), then the discovered
USB and serial ports will be listed. On
UNIX/Linux, a list of all possible serial ports are shown, but not all
of them may
actually be present on your system.
The -a option runs through the black and sensor
relative
calibration routines for the Xrite DTP92 and DTP94 instrument. If a
Spectrolino
is being used, then a white calibration will always be performed before
the instrument can be placed on the display.
By default dispread will either determine the
type of instrument if a USB port is selected, or for serial ports, one
must be selected using the -i
parameter. Note that the DTP92 and DTP94 are colorimeters, and cannot
read spectral information, and that the DTP92 can only read CRT type
displays.
Display type. Some colorimeters (like the DTP94)
can
do a more accurate jib if they know what type of display technology is
used. Use -yc if you are
calibrating a CRT (Cathode Ray Tube) type monitor, and use -il if you are calibrating an LCD
(Liquid Crystal Display).
By default only the colorimetric information (XYZ
value)
will be saved, but for instruments that support spectral readings (such
as
the Gretag Spectrolino), the -s option will save the spectral
readings
to the .ti3 file as well.
If a display video lookup table calibration .cal file is provided, it will be
applied to the display while the measurements are being taken, and also
included in the resulting .ti3 data file, so that profile can include it as a vcgt tag in the resulting
profile. The calibration file has usually been created using dispcal.
The -p
parameter allows you to position and size the test patch window. By
default it is places in the center of the screen, and sized
appropriately for the type of instrument. The ho and vo
values govern the horizontal and vertical offset respectively. A value
of 0.0 positions the window to the far left or top of the screen, a
value of 0.5 positions it in the center of the screen (the default),
and 1.0 positions it to the far right or bottom of the screen. The ss
parameter is a scale factor for the test window size. A value of 0.5
for instance, would produce a half sized window. A value of 2.0 will
produce a double size window. Note that the ho,vo,ss numbers must be
specified as a single string (no space between the numbers and the
comma). For example, to create a double sized test window at the top
right of the screen, use -p 1,0,2
.
When running on a UNIX based system that used the X11
Windowing
System, dispread normally selects the override redirect so that
the
test window will appear above any other windows on the display. On some
systems
this can interfere with window manager operation, and the -n
option
turns this behaviour off.
The -N flag disables any automatic instrument
calibration (used for the Gretag Spectrolino for instance). This would
be used when the instrument is being used for a series of measurements,
and it is inconvenient to place it on it's calibration tile between
measurements. The instrument should be calibrated at least once for
each measurement session though.
The -D flag causes instrument communications
diagnostics to be printed to stdout. This can be useful in tracking
down why an instrument can't connect.
The final parameter on the command line is the base
filename for the .ti1
input file, and the .ti3 output
file. dispread will add the .ti1 and .ti3 extensions
automatically.
If a large number of patches is being read, the screensaver on many
systems can interfere with the operation of dispread. It is therefore
advisable
in these cases to manually turn off the screensaver before commencing
the
measurements.
If communications break down with a USB connected instrument, you may
have to unplug it, and plug it in again to recover.
Some systems (Apple OSX in particular) have a special set of user
interface controls ("Universal Access") that allows altering the
display in ways designed to assist visually impaired users, by
increasing contrast etc. This will interfere badly with any attempts to
calibrate or profile such a system, and must be turned off in order to
do so. Note that certain magic
keyboard sequences can turn this on by accident.