SpaceMatch DCM User Guide

VCGT management for Windows PCs

SpaceMatch DCM enables the VCGT colour management of any PC connected displays, avoiding the problematic issues associated with ICC Profiles.

Using ICC profiles for PC display calibration is fraught with problems when used within the film and TV industry, as many graphics programs attempt to use any ICC based display calibration as part of their internal image colour management. This can often cause the final exported image to suffer unwanted colour changes.


SpaceMatch DCM User Guide

SpaceMatch DCM is a standalone .exe program. Simply unpack the download file and install the spaceman.exe program in to any folder of your choice; C:\SpaceMatch is a suggestion, and will be used as the location within this user guide.

When started SpaceMatch DCM will offer the chance to register and license. Registration details (and the option to register at a later date) are always available via the 'help\license' menu.

Initial Operation

When first started SpaceMatch DCM will read and display any active VCGT (Video Card Gamma Table) data, either previously loaded via SpaceMatch or via an ICC profile loaded through an ICC based calibration system.

If this is the first time SpaceMatch DCM has been loaded and started on a given PC system and an active VCGT is displayed it is imperative that the ICC based colour management system that loaded the ICC profile is located and deactivated or uninstalled. Before progressing further make sure this is accomplished, and that every time the PC is re-booted no new ICC profile is loaded into the VCGT, as shown by starting SpaceMatch DCM.

Note: If the already active LUT from a previous ICC profile might be required again use the 'Save' button to save the VCGT LUT in the default SpaceMatch LUT format.

If multiple displays are in use make sure this is true for all displays by locating the SpaceMatch program window within each display in turn, and use the 'Read' function to read the VCGT data for each display in turn.

SpaceMatch DCM

When first started a single LUT display window is active within SpaceMatch. New LUT display windows can be opened with the 'New File' button, or via the 'File/New LUT' menu. The new LUT window will also read the active VCGT data.

Assuming the LUT window shows no pre-active VCGT, as it should, the 'Load' button can be used to navigate to the required VCGT LUT and load it into the SpaceMatch LUT window.

Note: LightSpace CMS is used to perform the display profiling, and generate the required calibration LUT, with SpaceMatch DCM then applying the generated LUT to the display.

With the required LUT loaded into the SpaceMatch window, the 'Apply' button will apply the LUT, making it active by loading it into the video card driving the display SpaceMatch is presently located within.

With multiple SpaceMatch windows open, as in the above image, each LUT can be loaded by using the 'Apply' button within each SpaceMatch window.

At any time the LUT data held within the VCGT can be reset via the 'Reset Display Tables' button.

VCGT Issues

Windows VCGT Issues

The default Windows API/Reset process for the graphics card VCGT doesn't load a true Null LUT, as shown here. The peak value is lower than it should be, resulting in an inaccurate output throughout the entire LUT range.

By generating a true Null LUT within LightSpace CMS and using SpaceMatch DCM to load the LUT into the graphics card a true Null output can be attained.

Windows VCGT Error
VCGT Issues

Command Line Mode

To enable display calibration to remain active at all times SpaceMatch DCM comes with a command line mode that can be used to setup a Task Schedule, or Startup operation, depending on the OS. This enables SpaceMatch to be automatically activated, and load a specific LUT as soon as the PC is powered-up.

Note: The use of the Command Line mode assumes a basic understanding of its use. If in doubt, please refer to a knowledgeable Windows user.

Command Line Operators
The available SpaceMatch DCM command line operators are:

Usage examples, using the suggested default location and to load a LUT called lut.txt to display 1, would be:

C:\SpaceMatch\spacematch.exe -l lut.txt -d 1

Such a command can be run as a shortcut, or within Task Scheduler, set to run At Startup, or At Log on, etc.

Task Settings

Note: Make sure all associated Task configurations are correctly set as required, such as any necessary delay to allow the PC to finish booting before the LUT load is attempted, etc.

Remove All Other ICC Colour Management Programs

If any alternative colour management programs have been installed, including the activation of Window's own Colour Management tools, they must be deactivated as many will attempt to re-activate their own management without warning.

It best to uninstall all competing colour management software to prevent any conflicts.

For Windows Colour Management use the following instructions to disable its operation.