This tool has several different but related functions. When given as
a file argument an ICC profile containing vcgt "gamma" curves, or an
Argyll video calibration .cal file, it will load that calibration
into the chosen display. It can also install or uninstall a profile
in the system for the chosen display, or set the display calibration
to that in the currently installed system profile. By default it
displays a test window the same as that used by dispcal and
dispread, to test this functionality. It can also be used to test
the ability to load video card LUT curves to each display, and to
test how the console Bell will sound when used with some instruments
(ie. Eye-One Pro).
[Note that in OS X 10.7 Lion, changes to the default system profile
permissions mean that you can't set a calibration persistently when
the default system profile is being used, unless you run as root
(ie. use sudo). Note that you do not
need to run as root to install a user profile (-Su, the default
-display displayname [X11 only] Choose X11 display name
[X11 only] Choose the
display from the following list (default 1),
choose a different display m for Video LUT access.
Choose the display from the following list (default 1)
Display via a web server at port (default 8080)
Display via n'th ChromeCast (default 1, ? for list)
[MSWin] Display via MadVR Video Renderer
Display via dummy (non-existant, invisible) display
ho,vo,ss[,vs] Position test window
and scale it
= left/top, 0.5 = center, 1.0 = right/bottom etc.
= half, 1.0 = normal, 2.0 = double etc.
ss,vs: = optional horizontal, vertical scale.
screen with black background
encode output as (16-235)/255 "TV" levels
Run forever with random values
colors from CGATS file
Manually step through colors
video LUT loading & Beeps
display values (rather than through Video LUT and C.M.)
currently loaded Video LUT to 'filename'
linear display calibration (clear calibration)
calfile/profile cal. is currently loaded in LUT
Install profile for display and use its calibration
Un-install profile for display
install/uninstall scope for OS X [nlu] or Vista [lu]
one of: n = network, l = local system, u = user (default)
Load installed profiles cal. into Video LUT
[X11 only] Load all
profiles for given X11 server
[X11 only] Run in daemon
loader mode for given X11 server
diagnostics to stderr
calibration (.cal or .icm) into
LUT, and exit.
The -v flag makes the program more
When running on a UNIX based system that used the X11 Windowing
System, dispwin 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.
default the location of the test window will be the main display. If
the system has more than one display or screen, an alternate
display/screen can be selected with the -d parameter. If you invoke dispwin 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.
Note that if VideoLUTs for a
display are not accessible (i.e. no hardware calibration
capability), dispwin will
will issue a warning or fail when it attempts to access them.
On X11 the inability to access VideoLUTs could be because you are
trying to access a remote display, and the remote display doesn't
support the XF86VidMode extension, or perhaps you are running
multiple monitors using NVidia TwinView, or MergedFB, and trying to
access anything other than the primary monitor. TwinView and
MergedFB don't properly support the XF86VidMode extension for
multiple displays. You can use dispwin -r
to test whether the VideoLUTs are accessible for a particular
display. See also below, on how to select a different display for
VideoLUT access. Also note that dispcal will fail if the Visual
depth doesn't match the VideoLUT depth. Typically the VideoLUTs have
256 entries per color component, so the Visual generally needs to be
24 bits, 8 bits per color component.
More modern X11 systems support the XRANDR extension, which handles
multiple displays much more gracefully, but note that there are
limitations in profiling and calibrating Mirrored or Cloned
Displays. Mirrored displays share the same frame buffer space
(Separate CRTC's with overlapping pixel locations) but can have
different calibration curves, while Cloned displays share both frame
buffer space and calibration curves (A single CRTC feeding multiple
Outputs). dispwin will show different display selections for
each output, but calibration or application of color management may
only be correct for the last set display (i.e. if frame buffer space
overlaps, or there is only a single CRTC to hold calibration curves,
and a single _ICC_PROFILE_xxx root atom holding the profile, if the
application is using the Xinerama convention for obtaining a
profile, rather than the Xrandr per Output property _ICC_PROFILE
difficulty cause by TwinView and MergedFB in X11 based systems, you
can optionally specify a separate display number after the display
that is going to be used to present test patches, for accessing the
VideoLUT hardware. This must be specified as a single string, e.g. -d 1,2 . Some experimentation
may be needed on such systems, to discover what screen has access to
the VideoLUT hardware, and which screens the test patches appear on.
You may be able to calibrate one screen, and then share the
calibration with another screen. Profiling can be done independently
-dweb:port starts a
standalone web server on your machine, which then allows a local or
remote web browser to display the the color test patches. By default
port 8080 is used, but this
can be overridden by appending a :
and the port number i.e. -dweb:8001.
The URL will be http://
then name of the machine or its I.P. address followed by a colon and
the port number - e.g something like http://192.168.0.1:8080. If you use the verbose
option (-v) then a likely
URL will be printed once the server is started, or you could run ipconfig (MSWin) or /sbin/ifconfig (Linux or OS X)
needs to be enabled in your web browser for this to work. You may
have to modify any firewall to permit port 8080 to be accessed on
Note that if you use this method of accessing a display, that there
is no access to the display Video Lookup tables, and that any
operation that depends on accessing the VideoLUTs will either
generate a warning or fail.
-dcc or -dcc:no
causes test patches to be displayed using and available ChromeCast to
your TV. Use -dcc:? to display a list of ChromeCasts on your
local network. Note that the ChromeCast as a test patch source is
probably the least accurate of your choices, since it
up-samples the test patch and transforms from RGB to YCC and back,
but should be accurate within ± 1 bit. You may have to modify any
firewall to permit port 8081 to be accessed on your machine if it
falls back to the Default receiver (see installation
instructions for your platform).
[MSWin only] causes test patches to be displayed using the MadVR
video renderer. Note that will have to start MadTPG before
running dispread, and that while you can adjust the "Test Pattern
Configuration" controls, you should not normally alter the
"Existing Calibration" controls, as dispread will set these
appropriately. See -n flag.
causes test patches not to be displayed at all.
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, or 10% of the width of the
display if the display size is unknown.. 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. If three
parameters are provided, then 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. If four parameters are provided, then
the last two set independent horizontal and vertical scaling
factors. Note that the ho,vo,ss or ho,vo,hs,vs 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
. To create a window twice as wide as high: -P 1,0,2,1.
flag causes the while screen behind the test window to be masked
with black. This can aid black accuracy when measuring CRT displays
flag causes the test values to be scaled to the Video RGB encoding
range of 16/255 to 235/255. Note that this is not applicable if the
MadVR render is being used to display patches, as MadVR should be
configured for Video encoding instead.
By default dispwin will put
a test window on the selected display, and display some test colors,
before darkening then brightening the screen by loading video
LUT values, test the bell sounds, then restore the original values
If the -i
flag is set, then dispwin
will display the preset sequence, then random test colors forever.
If the -G
parameter is set, then dispwin
will display the sequence of RGB color in the supplied CGATS file,
e.g. a .ti1 file. Typically this might the used with the -m option to manually measure a
set of test patches.
If the -m
flag is set, then dispwin
will display the preset sequence then exits, but advances manually
after each return key.
If the -r
flag is set, then dispwin
will test just the loading of video LUT values by first darkening,
then lightening the screen, before exiting.
If the -n
flag is set, then dispwin
will display the colors directly on the display, rather than having
the color values translated through the currently loaded Video LUTs.
In the case of using the MadVR renderer to display the patches, any
3dLut will also be disabled.
If a -s filename.cal option is
used, then rather than displaying a test window, dispwin will save the currently
loaded calibration curves to the given calibration file. Note that
other functions such as clearing or loading a calibration can be
performed after this action.
If a -c
flag is used, then rather than displaying a test window, dispwin will load the selected
display with a linear set of Video LUT curves, effectively clearing
the calibration, and will then exit. Note that other functions such
as loading a calibration can be performed after this action.
If a -V
flag is used, then rather than loading the calibration specified as
the final argument, the currently loaded calibration will be
verified as being the same as the given calibration file. If this is
combined with the -L flag, the currently
loaded calibration will be verified as being the same as the
installed system profile for the display.
-I: The ICC
profile specified as the final argument will be installed as the
default operating system profile for the chosen display, and the
display calibration will be set to the calibration tag ('vcgt' tag,
if any) in that profile. On MSWindows and OS X this means that the
profile will be copied to the appropriate color profile directory
and registered with the operating system.
For Linux X11 systems, the profile will be installed using using the
ucmm convention by default, and this
associates the display hardware identification (EDID) of the
selected display, with the profile. The X11 _ICC_PROFILE property
will be set in the root window, and also the the XrandR 1.2 X11
_ICC_PROFILE output property on systems that are running XrandR 1.2
or later. The use of atoms is following this convention
for allowing applications to locate the display profile for a
particular X11 display, and expands it to accomodate XrandR 1.2.
Note that for X11 systems, the properties are not persistent, and
will need to be loaded each time the X11 server is started (see the
If the ARGYLL_USE_COLORD environment variable is set (ie.
set it to "yes"), then on Gnome systems running colord, dispwin will attempt to store and retrieve display ICC profiles using
To make sure that the profile calbration 'vcgt' tag gets loaded into
the Graphics Card at system start, please read the guide here.
-U: The ICC
profile specified as the final argument will be un-installed as the
default operating system profile for the chosen display. The display
calibration will remain unchanged.
-S d: Some
systems have more than one profile scope that an installed profile
will apply to, and this parameter allows overriding the default user
scope. On OS X, there is a choice of three scopes: n: for network scope, if people
are sharing profiles over a network, l: local system scope, which installs the profile
for all users of a system, and the default u, which covers just the user
installing the profile. On Linux or Microsoft Vista, just the local
system l and user u scope are available. Note that
you may need to run dispwin with elevated privileges(sudo) to be
able to successfully use network or local system scope. This option
also applies to uninstalling a profile. Note that to install a user
profile for the root account, you will have to login as root (sudo
will not achieve this).
option fetches the current installed system profile for the chosen
display, and sets the display to the calibration tag ('vcgt' tag, if
any) in the profile. This is a convenient way of initializing the
display on system startup from the installed display profile, if the
system doesn't not do this automatically .
running on a UNIX based system that used the X11 Windowing
System, it will load the installed profiles of all the screens
of the given X11 server. This may be useful on startup, or when
called from a udev script triggered by attachment of a display.
mode (experimental). When running on a UNIX based system that used
the X11 Windowing System, this option runs dispwin in a "daemon"
mode where it monitors the given X11 server, waiting for any changes
in monitors that may require loading a matching ICC profile (ie.
such as re-configuring, plugging in a different monitor etc.)
This only works if XRandR 1.2 is available on the server. By default
dispwin runs silently, and will not terminate. If the -v option is given, it will emit
messages to stdout to show what it is doing. When it is first
invoked, it will load the installed profiles of all the screens of
the given X11 server.
The -D flag causes diagnostics to be printed
to stdout. A level can be set between 1 .. 9, that may give
progressively more verbose information. This can be useful in
tracking down why an operation fails.
The final optional parameter on the command line
is the name of an ICC profile that contains a Video LUT vcgt tag, or an Argyll .cal format display calibration. If
this parameter is provided, then the selected display will be loaded
with the given calibration. If the -V
flag was given, then it is verified that this calibration is the
currently loaded one. This may be useful in initializing a
system to the current calibration on system startup, although a
better way may be to install the profile (-I option), and then just use -L. Note that the vcgt tag
interpretation within Argyll is consistent with that of the
originators of the tag. Other ICC profile vcgt implementations may
not be so consistent.
NOTE that on an X11 system,
if the environment variable ARGYLL_IGNORE_XRANDR1_2
is set (ie. set it to "yes"), then the presence of the XRandR 1.2
extension will be ignored, and other extensions such as Xinerama and
XF86VidMode extension will be used. This may be a way to work around
buggy XRandR 1.2 implementations.
NOTE on MSWin systems that you will have to disable any
other calibration installer program if you want to be able to
control calibration using dispwin. Note also that there are other
programs that will interfere with calibration loading, such as
igfxpers.exe that gets installed with nVidia "Optimus" technology.