[EDIT 2018-01-12: I should've probably posted in a different thread, as what I'm describing is a process for improve the colour accuracy of the JVC colour profiles (Rec. 709 or BT.2020) using HCFR (or other calibration programs) based on i1D3 measurements. It is not related to the 3-phase Autocal. The custom profiles are not correcting the Spyder measuring errors, but are correcting the profiles directly. As a matter of fact, it does not involve running gamma or colour calibration or even the Spyder at all; the JVC software is only used for creating and uploading the custom profiles.]I suspect I'm missing something here, as per Posts 9 and 10 in this thread, providing detailed recommendations for JVC Autocalibration, a Color only Autocal was advised for BT2020-NF, following the Gamma+color Autocalibration using a standard Color Profile and 'normal' Gamma (for each combination of lamp, iris, CMD state, etc.).
This seemed to be an established procedure. Is this now being called into question?
I bought a DLA-x570R (RS420) last week and have confirmed that Autocal fine-tuning works for BT2020NF. Here's what I did, using HCFR and i1D3:
- Create a custom profile BT2020NF even though it should be the same as the built-in BT2020 (the projector has no wide gamut filter); upload it to the projector
- Measure grey scale
- Run saturation sweep for primary colours
- Measure the ColorChecker patterns for reference
- From the grey scale xy errors, calculate the white point xy for the custom profile BT2020Corr (similar to Chad B's fine-tuning)
- From the saturation errors, calculate the xy values for Red and Blue (similar to Chad B's fine-tuning). I did not touch green as it's seriously undersaturated (beyond redemption)
- Create the custom profile and upload it to the projector
- Remeasure the grey scale, saturation sweeps and ColorChecker patterns.
Even with just a single attempt, the greyscale dE improved from 3.7/7.5 (Average/Max) to 1.0/2.2. The ColorChecker dE improved from 1.7/4.7 to 1.4/3.5. I should be able to make further improvements with another iteration.
Note that the same improvement to the greyscale dE can also be made using the projector's RGB Gain and Offset controls; I was able to achieve an even lower dE of 0.6/1.1 as the feedback is instantaneous.
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