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.