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I’ve been calibrating using an i1d to produce a rec 709 LUT with 2.2 gamma both for Resolve and eeColor to drive a wide gamut display via Decklink, and noticed a slight grey scale differences with the two LUTs. A new calibration with different settings fixed it (actually Resolve still gives a slight artifact not present in the eeColor, but the main difference is gone), however I’m not sure if I’m calibrating correctly wrt. the tone curve. Any help would be great!
To produce the 3D LUT I selected Rec 709 / 1886 for Resolve first, set white level to 120, left black/tone “as measured” on calibration settings, Gamma 2.2 on the LUT tab, calibrated and produced the LUT. I then turned off vcgt and “create 3D lut after profiling” as per instructions, changed the LUT format for eeColor and created for that. Although the results using Resolve’s LUTs feature vs. the eeColor were close, when viewing a black white gradient there was a slight difference to the position of where the white level increased noticeably.
I produced a new calibration for 709 / 1886 but this time selected Gamma 2.2 for the tone curve on calibration settings as well as on the LUTs tab, and also unchecked vcgt before producing the first LUT. The two LUTs then worked near enough identically.
Is my latter approach correct, disabling vcgt and selecting a matching Gamma on the calibration settings to produce the LUTs, or might this now have produced an incorrect tone response? Getting the levels in the blacks right is particularly important for colour correction work, so I’m keen to not have those off through messing up the settings during calibration!
Hi,
not sure I understand. So the wide-gamut display is driven exclusively via the decklink, and the eeColor is in-between decklink output and the display? In that case it would be enough to apply the 3D LUT via the eeColor (only). Or are you aiming for the GUI (displayed on a different monitor) to be also corrected via a (different) 3D LUT?
Hi Florian, thanks for the reply and the software, your dedication to the project is amazing.
Overview: The setup is a 2716 on DeckLink (now with eeColor in the path), plus another 2716 for Resolve’s main UI and a smaller display for scopes both on a 1070 GPU. I calibrate the DeckLink monitor via the 1070 and then switch the monitor from DP input to HDMI coming from from the eeColor/Decklink. I do want the DeckLink and main UI to be consistent. At first I had all monitors on the GPU and used Resolve’s monitor and color viewer LUT options for corrections. This worked well and the monitors were matched great, but Resolve’s LUT feature isn’t really intended for applying monitor calibrations, and in some cases you might get the wrong colours or LUTs being used for the monitors, no LUT at all if on the Media page (a shock with wide gamut), and even wrong data in the scopes by default with a monitor LUT set. The LUT settings are carried in project settings not preferences, and it’s too easy to make setup mistakes as well as being inconvenient to use.
So trying the eeColor, I loaded a unity LUT in the first setting and an eeColor version of the Resolve LUT in the second, and was comparing back and forth between Resolve with LUT + eeColor Unity and Resolve with no LUT + eeColor LUT to verify that the results were the same. No colour issues, but the slight difference with a gray scale gradient.
So re-calibrated and I’m happy with the new calibration and LUTs as they’re consistent, but I’m unsure whether turning off vcgt and setting a 2.2 tone curve on the calibration tab rather than using “as measured” was the right thing to do or whether it’s important to have it left to as measured, or even if the tone curve setting on the calibration tab only matters for a 1D LUT etc. I’m also not sure if the first/second colour files are necessary to be uploaded to the eeColor; I have, but I don’t think it changed the output from when I had uploads in it from calibrating a projector.
So re-calibrated and I’m happy with the new calibration and LUTs as they’re consistent, but I’m unsure whether turning off vcgt and setting a 2.2 tone curve on the calibration tab rather than using “as measured” was the right thing to do or whether it’s important to have it left to as measured, or even if the tone curve setting on the calibration tab only matters for a 1D LUT etc.
It is ok to calibrate to a particular tone curve as long as you install the resulting profile which (also) contains the calibration (if the calibration is not applied to the 3D LUT, it needs to be applied in another way, hence the need to install the profile).
Thanks Florian, so for the eecolor, does that mean also uploading the first rgb and second rgb files as well as the LUT file to the box?
