Revision for “Setting up untethered” created on February 20, 2018 @ 17:08:49
Setting up untethered
Please note that the untethered mode should generally only be used if you've exhausted all other options. Measurement runs in untethered "Auto" mode will typically take at least twice as long as through other methods. Setting it up correctly can be tricky, so this is attempting to give some hints to make setup easier. Note that "Auto" testchart can not be used in conjunction with untethered mode. As the untethered "Auto" measurement mode takes at least two readings per patch, and looks at changes in lightness, hue and chroma to determine if the patch has changed, and the minimum time a patch needs to be displayed to allow it to be measured depends on the patch lightness, the integration times for white and black of the instrument on the specific display used need to be known so correct minimum times can be chosen. You can use the untethered mode to determine those times (disable "Auto" measurement mode checkbox on the "Untethered measures" window for the time being so you can do manual measures). Show a black patch on the display, then click "Measure" (it's not important which patch in selected in the "Untethered measures" window). Use a stopwatch or other means to note the time it takes to measure. Repeat for white, then re-enable the "Auto" checkbox and close the "Unthethered measures" window. Now you have to prepare the testchart you're going to use. To do this, open the testchart editor for the selected chart, and choose "Maximize lightness difference" from the "Sort by..." dropdown, then click "Apply". Save the testchart and choose "Yes" when asked to select it. Click "Export". Choose an image file format (DPX, PNG, TIFF) and click "Save". You can now use the measured integration times to set suitable "max repeat" (which is the value for black) and "min repeat" (which is the value for white) values. E.g. if the measured integration time for black was six seconds, and the measured time for white one second, and the assumed playback rate of exported patches was 1 fps, you'd set "max repeat" to at least 12 (6 * 2), and "min repeat" to at least 2 (1 * 2). It is usually a good idea to add some margin, e.g. in the example you'd add roughly 4 for "max repeat" and 1 for "min repeat" to bring them up to 16 and 3 respectively. Click "OK" to export the image files. Start the measurement process. Show the first exported image file on the display and click "Measure". Continuous measurement mode will start. Now you have to start playing back the image files in ascending filename sort order on the display.