New HDR Calibration Procedure (SK 0.11.1 + HGIG)

Except for a few early HDR games, as long as you calibrate them correctly they should adhere to HGIG guidelines.

Some of them have really lousy calibration screens that don’t cover the full range of luminance you can expect during gameplay, and for those games you need dynamic tonemapping because they’re going to frequently go above range and you’d lose image detail constantly.

Thank you for the reply Artem, this does bring me to another issue though I was trying to dial out the pink as best I could using both methods in Watch Dogs (as best I could the mouse issues in that game made it difficult…) and I could never get the pink to go away, any idea whats up with that? I assume by pink it is meant magenta?

Which Watch Dogs? Legion is a true HDR game, so requires the HDR10 Tonemap mode, which gives you virtually no control over this stuff, you have to use the in-game HDR calibration.

First one, I think I may give up on it though since the game hates trying to adjust settings in special k with the mouse, I thought I had something that worked but my blacks were too crushed.

  • Disable mouse input to the game with SK’s Input Management / Device menu.
  • For black crush, either use Passthrough or 0.725 SDR -> HDR gamma

Actually, come to think of it… Watch Dogs_2 uses sRGB, so the gamma needed would be .476, I assume the original Watch Dogs is simiarly doing things wrong :slight_smile:

Yeah I tried the mouse disable thing but no dice, id use my xbox controller but I am unable to get to the HDR window to make adjustments with it unless there is some combo I am not aware of. I am also on a 4k display which isnt helping since its a lot of pixels to cover.

That actually reminds me though, when I bring up the HDR widget it informs me foron the bottom right my display is a BenQ XL2420TE, which one is hooked up to my computer but windows isnt outputting to that when I use HDR content on my TV.

Can this be disregarded or can it be causing issues for me trying to get HDR with SK?

Hold down the X button, and then the right bumper to cycle through widgets, then just use the D-Pad to select parts of it to configure.


It’s probably irrelevant, getting the name of a monitor is difficult, getting the EDID for the attached monitor is not :slight_smile: I suspect EDID data is accurate, name is not.

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It’s technically pure red, just at the brightest level your display supports. Not sure how to describe that other than pink :slight_smile: It will appear pink contrasted against colors at normal luminance levels.

If anyone wants to help test:

SpecialK64.7z (7.6 MB)

This version adds a Paper White Luminance slider (default = 250 nits) to control the mid-tone luminance level. Setting this lower is important in some games (i.e. NieR: Automata) that do not handle gamma correctly in their original SDR form (lol).

This should become the official release of 0.11.1 as soon as I re-write this calibration guide. Make sure to reset HDR preset values, especially paper white.

I’m very confused by the “new” sliders.

With the previous peak brightness/max luminance and paper white settings, I was able to achieve satisfactory results in Jedi: Fallen Order, using an approximation of my TV’s actual specs, an LG C9 (700 peak brightness, 300 paper white, full luminance disabled). Now, following your guide for HGiG calibration, the image doesn’t look right.

To eliminate pink spots/pixels, I have to lower the middle gray by a lot. Changing the peak brightness, as you suggested, produces weird pink spikes every few steps (as if pinks were increasing and reducing in size in waves). I got it to stabilize every 200 or so (left at 799). Paper white doesn’t seem to do much other than “brighten” and “darken” the overall picture. Same with gamma boost. Also, you’re supposed to eliminate all pink by adjusting peak brightness, but you later say to keep them at less than 50%?

That’s with ACES. With the other mode (no middle gray adjustment), I can get close to what I had with a previous version of SK. That version also had Remaster 10- and 11-bit selected by default, while no Remaster options are selected on the latest release (and I have no idea what to do with them).

Adjusting HDR can be exhausting, the reason why I play in SDR 99% of the time. These settings aren’t exactly user-friendly. =/

Don’t follow the calibration guide here, there’s a reason I mentioned I need to re-write it.

The maximum luminance slider changes the scale of the HDR visualization at 1999, 1499, 999, 799, 599, 399 nits and makes the procedure previously described invalid.

    // Closest appropriate published ref. val
    if (fUserTarget >= 1999.0f)
      _fSDRTarget = 343.0f;
    else if (fUserTarget >= 1499.0f)
      _fSDRTarget = 276.0f;
    else if (fUserTarget >= 999.0f)
      _fSDRTarget = 203.0f;
    else if (fUserTarget >= 799.0f)
      _fSDRTarget = 172.0f;
    else if (fUserTarget >= 599.0f)
      _fSDRTarget = 138.0f;
    else if (fUserTarget >= 399.0f)
      _fSDRTarget = 101.0f;
    else
      _fSDRTarget = 80.0f; // This ain't HDR!

Also, ACES should be producing no pink pixels at all. So if you use the ACES Filmic mode, none of this even applies.

Just set maximum luminance as high as you can, then find a paper white luminance that looks pleasing.

Calibration is much simpler now, you’re overthinking things and trying to follow a guide that was not written for this version.

Within TW3 I can set peak luminance to 1300, paper white to 450, middle grey to -7 (black crush) and comparing it to previous version it does look better (however requires more work)

Only issue is to achieve the same level of saturation I need to push it from 105% on older versions to 120-125%. Is this an issue? I dunno, just feels off.

Oh and this version all the remasters are set to off by default.

Yeah, I’m defaulting them all to off by default now because fewer compatibility issues that way :stuck_out_tongue: It won’t give the best results, but will save me a lot of time explaining stuff to people.

More than likely the same level of saturation is gonzo levels of oversaturated. I put in a bit of work to make sure you can control luminance without also oversaturating colors. If you really want those levels of saturation, you can ctrl+click that slider and go as far as 200% (but that’s crazy).

About the saturation, everything just looks muted regardless of what I do, 200% sat, max paper white. Every settings results in a muted image even compared against SDR

Hades, TW3, Prey, Hollow Knight IMO looks best on older version of SK then SDR then this test version. Control the new test version does look better imo, has better separation of what should be outside of SDR limits and doesn’t have highly saturated colours in the first place.

To go along with this, as we are using LG OLEDs on a PC, do we need to adjust the colour gamut manually past auto to enable use of DCIP3? Yes you can check via SK if you have colours that go outside certain containers but is the screen actually showing this?

I ask because if you do manually unclamp the gamut on the TV the image is more saturated which makes little sense to me as it should automatically detect it’s being fed a WCG source?

Are you sure all settings are in their neutral position? Gamma and middle-gray contrast will affect saturation.

The only adjustments that do not directly affect saturation are Peak Luminance and Paper White Luminance (though the range between Paper White and Peak White receives a slight boost to saturation).

Technically, there is only one correct way to interpret an HDR signal – Rec 2020. Those various gamut settings in the TV’s settings all control how much of the gamut to try and use.

None of them are strictly correct for HDR, that would require Rec 2020 and displays that cover 100% of Rec 2020 don’t exist :slight_smile:

I think what they affect is how much room at the extreme edges of the display’s native gamut is reserved to try and gradually roll-off colors outside the gamut before simply clipping to a maximum saturation. Colors at the gamut boundaries are never accurate on TVs because they’re designed with cushioning for out-of-gamut colors.


Same is true of luminance, TVs will try to tonemap things back into range unless told not to. Reference displays always clip, consumer displays do whatever the hell they want unless they have a special mode such as HGIG that requires a certain behavior.

It might be helpful if you took a few HDR screenshots either with SK’s Steam overlay integration, or using the Xbox Game Bar (Win + G).

If you can provide me copies of the actual HDR screenshot (.jxr) for comparison (old version vs new version), I will have a better idea what aspect of the image you think looks better in the older version of Special K.

Yup, see images: (25mb, had to upload them elsewhere)

https://pixeldrain.com/u/KDHF7Nkn Hades Old SK Stock.jxr
https://pixeldrain.com/u/bRhvSrcd Hades Test SK Max Paper White.jxr
https://pixeldrain.com/u/Z8FC2H7Y Hades Test SK Stock.jxr
https://pixeldrain.com/u/71BzRx11 Hades SDR.png

The older SK gives me an image that I expect from an SDR to HDR remaster, the test version looks muted. No amount of tweaking gives me a result that is like the older version / I actually like the look of.


https://pixeldrain.com/u/wvt9RcjA TW3 OLD SK Stock.jxr
https://pixeldrain.com/u/2Yo54h8K TW3 Test SK Adjusted.jxr
https://pixeldrain.com/u/j3316qcC TW3 Test SK Stock.jxr
https://pixeldrain.com/u/m97nYgNz TW3 Test SK Stock 110.jxr
https://pixeldrain.com/u/abn3yFWy TW3 Test SK Stock 125.jxr
https://pixeldrain.com/u/q116cKzn TW3 SDR.png
https://pixeldrain.com/u/cgpCMv94 TW3 Test SK Passthrough.jxr

You can easily tell that the brightness “control” with the new version is better with Paper White but saturation imo doesn’t feel correct. Is this because I am used to an overly saturated image? I don’t know S:

Oh, I see… the more saturated version does look better. It’s hard to tell which is more correct without an SDR screenshot (for The Witcher) as a reference though.

BTW, have you tried the Passthrough tonemap mode? You will loose the ability to tune a number of parameters and just be left with Peak / Paper White and Gamma, but it is likely to saturate things to the levels you are familiar with from older versions.


For Hades, I’d say the new version is closer to what the image is supposed to look like, though ideal saturation is probably somewhere inbetween new and old.

Included an SDR image for TW3, can easily see what the level of saturation they went with (This is the expansion for the game, the base game it is a lot less saturated and with the new SK it looks very bland)

I have but only briefly, could never dial anything in that looked evenly remotely as good as ACEScg. I’ll give it more of a look now.

I tried, it, for this one scene it strikes the best balance between old SK and new SK

https://pixeldrain.com/u/cgpCMv94 TW3 Test SK Passthrough.jxr

That would be because I uploaded the image with the HDR processing % fully on… Edited the original post with all the links.

In theory, if you set the Peak White and Paper White values identical, it should spit out the same oversaturated image as it used to.

The old image processing was treating red, green and blue channels as having identical luminance, which could not be farther from the truth. Blue is only like 10% the luminance of green and red is 25%.


Try this version please:

+ Added button to Reset HDR Presets to HDR widget

 >> Later versions will add buttons to import and export presets from previously
      configured games

+ Fixed widget slider / dropdown behavior so that it blocks mouse input to game
+ Added DXGIGetDebugInterface1 (...) to SpecialK{64|32}.dll for games that need it

SpecialK64.7z (7.6 MB)

The reset button should make life easier for everyone :wink: