Hi Guys,
Here's a high level description (lol) of a workflow used for a Profile run of a mini3 connected to a Display. The Profile run was done to determine the level of quality of the LUT calibration of the 5x5x5 mini3 external LUT processor connected to the Sony display. This is a Worst Case Scenario workflow ... which is defined by having a display with very poor image processing. Step 1 selects the Just Good Enough LUT size of the Profile run. This step is dependent on how good the Display's (w.o. mini3 connected) image processing capabilities are. Step 2 describes the steps used to Judge the quality of the display based on Profile run whose LUT size was determined in Step1. There are many undercurrents going on here (like the size of the mini3 LUT), so it's a simplistic view (lol). To clarify: this WCS workflow reflects the extra steps needed because the display's poor quality. A display with good image processing capabilities uses the Short Run (a) as its Final Profile Run in Step 2. A poor display uses the Long Run (b), with varying LUT sizes, as its Final Profile Run in Step 2. We assume both the mini3 and Chromapure cal software (used to calibrate the min3/display combo) are of good quality and do not influence any additional steps in the WCS workflow. You could use calman instead of Chromapure, as well, with the same good quality assumption.
Quality LUT Workflow:
1. Perform 2 Quick Profile runs of the Display by itself, without the mini3 connected. Your objective in this step is to select a "Just Good Enough" LUT size (either the small Quick Profile size or one of the larger 10-17pt sizes) to use for the Final Profile Run in Step 2. You'll determine the LUT size by judging the quality of the Display's Color Separation, Gamut and Gamma from the Quick Profile run, independent of the mini3. Again, the mini3 is not connected for these 2 Quick Profile runs:
a. The first run: perform a Quick Profile run with the display's internal calibration engine turned off; the Pre-Calibration Workflow is: get the display in Full Default conditions (i.e., all enhancement features turn off, color temp closest to D65, no changes to other monitor controls ... keep the unit show room bright). This will give your display the best chance for showing excellent color separation. We'll also determine if you have a very poor quality display by the color separation results here;
b. The second run: perform a Quick Profile run with the display's internal calibration engine turned on; follow Light Space's Pre-Cal Workflow;
c. If the Display color separation fails both runs, when the display's internal calibration engine is off and on, then you'll use 17pt profile size, which takes 4 hours to run. Go to Step 2 (b), Long Profile Run;
d. Else, if the first run passes and the second run fails, pick a Profile size between 10pt – 17pt, which takes between 1 to 4 hours to run. Deciding this requires a more experienced base than I have, so for newbies, just pick the 17pt size, which takes 4 hrs. Go to Step 2 (b), Long Profile Run;
e. Else, if the Quick Profile color separation, gamma and gamut passes both runs, cal engine off and on, then pick the Quick Profile LUT size (Quick Profile has only 1 LUT size), which takes 10 minutes to run, for Profiling the mini3/Display combo. Go to Step 2 (a), Short Profile Run.
2. Once you've completed Step 1, connect the mini3 to the display, calibrate the mini3/display combo using Chromapure (or Calman) and determine the level of quality of the LUT calibration with Light Space by doing the following based on which Profile LUT size you picked in Step 1:
a. Short Profile Run: Quick Profile Size ... i.e. Small Size Profile LUT:
i. Last Profile Run: Perform a Quick Profile run on the mini3/display combo. While still in the Quick Profile tool, Judge the quality of the Color Separation, Gamma and Gamut. You can't see color separation if you exit the tool.
ii. Create a Calibration, rec709, LUT and Judge the quality of the CLUT image of your calibrated display, in terms of shape and any distortions ... (tbd, Steve, help pls.).
iii. Create a Verification LUT and Judge the quality of the VLUT by looking at Reference Images through the VLUT of your calibrated display.
iv. Based on your experience base, you can now determine the level of quality, based on the 3 previous judgments, of the LUT Calibration of the mini3/display combo. The actual calibration was done by Chromapure with the mini3 connected to the Sony display. Light Space is only used to determine the level of quality of the LUT calibration.
b. Long Profile Run: 10 to 17pt Size Profile Run ... i.e. Large Size Profile LUT:
i. Based on the size of the profile you selected (10-17pt); perform a Display Characterization Profile run of the mini3/display combo. Remember the data file name you assigned for the next step.
ii. Create a Calibration LUT, rec709, Image by selecting the DC Profile data file name in the destination box. It's the file name you were asked to remember in the previous step. Now, remember the CLUT file name you just assigned in this step for the next step.
iii. Last Profile Run: Use Quick Profile (yes, another Quick Profile run, 10 minutes, is needed) and perform a Re-Quick Profile by clicking the Active LUT box and selecting the CLUT name you were to remember. This run should take 10 minutes;
iv. Judge the quality of the Color Separation, Gamma and Gamut of the Re-Quick Profile run.
v. Create a Calibration, rec709, LUT from the Re-Quick Profile and Judge the quality of the CLUT image of your calibrated display, in terms of shape and distortions ... (tbd, Steve, help pls.).
vi. Create a Verification LUT and Judge the quality of the VLUT by looking at Reference Images through the VLUT of your calibrated display.
vii. Based on your experience base, you can now determine the level of quality, based on the 3 previous judgments, of the LUT calibration of the mini3/display combo. The actual calibration was done by Chromapure with the mini3 connected to the Sony display. Light Space is only used to determine the level of quality of the LUT calibration.
Bottom Line:
To determine the Level of Quality of a LUT Calibration Run, one needs to determine the Image Processing Capabilities of the mini3/Display combo. You start by selecting the size of the LUT that is Just Good Enough to be used in the Profile run. This depends on the quality of the imaging processing capabilities of the display by itself (not connected to the mini3). Since you may not know the quality of your display and you want the fastest run with Just Good Enough accuracy, follow Step 1 of the LUT Quality Workflow to determine this. Step 1 results in identifying the Just Good Enough LUT size for the Profile run. You'll need a minimum of 3 short Profile runs for a high quality display. A minimum of 4 Profile runs, some which are 1 to 4 hour(s) long, for a poor quality display. Most displays should use the Short Run, but you won't know unless you follow this workflow. You'll note that I marked where the Last Profile Run is in the workflow process for both the Short (a) and Long (b) profile runs. If you used the Short, 10 minute, Profile Run as the Last Profile run, it took you 3 Profile runs, a CLUT and a VLUT (a hidden Quick Profile Run is needed here) to Judge the quality of the calibration run. If you used the Long Profile Run, it took 4 Profile runs, some which are 1 to 4 hour(s) long, a CLUT and VLUT (a hidden Quick Profile Run is needed here) to Judge the level of quality of the mini3/display combo LUT calibration run. The Last Profile Run is the actual JGE Profile Run of the mini3/display combo. It should give you the fastest run time with a high enough confidence that the accuracy is very good. This Profile run assumes an already calibrated mini3 was connected to the display. The mini3/display was calibrated in my tests with Chromapure, but you could use Calman as well.
Kind Regards, JJ |