Epson LS12000 Dynamic SDR + HDR – Take 2

I spent more time with the LS12000 today and there are a few more findings, settings and a present for you in this article.

CCSS

30 Jun 2022: This section has been edited for accuracy.

Colorimeter Calibration Spectral Set (CCSS) is the file ArgyllCMS and HCFR (current release as of 30 Jun ’22 here) uses to tailor colorimeters to displays that support CCSS files. For example, the i1 Display Pro is calibrated in the factory and this calibration is stored in firmware. The i1 Display Pro also comes with EDR files (same as a CCSS but in a different file format) that allows it to be tailored to the display technology you want to calibrate. The issue with the EDR set is that they haven’t been updated for ages and they are not really suitable for laser projectors.

While it would be more accurate to create a CCMX for a particular display – colorimeter – spectrometer combination, a benefit of CCSS is that it is transferrable between display units and between colorimeters. The CCMX is not really transferrable so it is best not to download one and use matrix offsets from someone else’s CCMX / correction matrix

To use the CCSS calculated for the LS12000, you need to install HCFR / ArgyllCMS and then pop it into a Color folder under C:\Users\YOUR_NAME\AppData\Roaming\Color. You will need to show hidden files and folders in Windows to be able to access this folder. Then you can use HCFR – or any other application that uses Argyll – to calibrate the LS12000 with your i1 Display Pro / Colorchecker Display / Colormuki Display / Spyder 4 / Spyder 5 devices. (I don’t actually think the Spyder X can use CCSS files, unfortunately.)

You can download CCSS file below for the Epson LS12000. The CCSS was taken with the laser at 466hours. It can be used between about 0 and 5000 hours on the laser after which it might lose it accuracy somewhat. The below CCSS was taken with an i1 Pro 3 in High Resolution (3nm) mode.

If you’d like to calibrate your Epson, you can find some resources here.

Please note that due to unit and screen variances, the calibration may not be transferrable. However, the calibration settings might help tame your LS12000 in dynamic mode until you get a professional calibrator, or you do a calibration yourself.

I also confess that this is still not complete victory in taming dynamic mode on the LS12000. It usually takes a few tries before I get the hang of such a non-linear mode. These modes are challenging to calibrate regardless of your experience level.

Dynamic Calibration – SDR Torch Mode

See the adjustments below. I used two-point greyscale with this calibration to demonstrate how such a thing could be achieved and it lined up relatively well. I started doing an 11-point greyscale but ran out of time – I wanted to focus on the CMS this time. You can use the previously published white balance and 11-point greyscale with the CMS adjustments if you want! That was more detailed but didn’t have the CMS adjustments. Here they are below.

  • Dynamic Picture Mode
  • Laser power: 100% (torch mode)
  • Dynamic Contrast: High Speed
  • Gamma: -1
  • Dynamic Gamma: 8
  • Image Enhancement –> dynamic contrast: 8

See White Balance and CMS adjustments below:

Notes

Calibrating dynamic mode on the Epson is a bit of a challenge to say the least. This is why most professional calibrators won’t even touch such a picture mode. Natural would have taken less time and been a lot more accurate. But what’s the fun in that – especially as dynamic mode has aggressive laser dimming.

The greyscale in SDR lined up nicely. See below. I could have done better by adjusting it using a 11-point greyscale but wanted to focus on the CMS.

The Colour Management System (CMS) does not switch into REC709 mode in Dynamic so the gamut is oversaturated, especially in red and green. However, it can be tamed to a point where it looks accurate under 75% saturations. See the before and after below.

Dynamic Calibration – HDR Torch Mode

  • Dynamic Picture Mode
  • Laser Power: 100%
  • Brightness: 2 (due to having touched offsets) – you can use an HDR Black Level adjustment pattern to set black to code level 64 (to standard ) or to 77 (to get around lifted black level in mastering) if this setting doesn’t quite work. You can also lower this to 1 if the blue push near black bothers you.
  • Dynamic Contrast: High Speed
  • Gamma: 0 ( -1 for dark cave might work better)
  • Dynamic Gamma: 8
  • Image Enhancement –> dynamic contrast: 8
  • Adjusting blue push near black: I didn’t have time for this today, but you could use the bottom stimulus level on the 11-point greyscale controls (stimulus 1) to increase green and red, then re-adjust the brightness control using an HDR Black Level pattern.

Notes

There are two methods to calibrating the Epson for HDR:

  1. Calibrate to 2.2 gamma in SDR – then check that EOTF lines up once switching the unit into HDR mode. It normally does!
  2. Use an EOTF calibration on top of the SDR 2.2 gamma cal and change the EOTF multiplier / brightness after switching Epson into HDR mode. I will publish such a calibration for the TW9400 / UB6050 / UB5050 in the next week or so to demonstrate this. It allows users with bigger screens to have more HDR brightness. It can be used with an LS12000 as a method also.

Thankfully, the EOTF was correct when the Epson was switched into HDR after having calibrated the gamma to 2.2. However, the greyscale did need more work specifically in HDR. The issue in HDR mode is that I introduced a slight blue push in the low end that is difficult to calibrate out without using multi-point greyscale controls. That is certainly a better strategy.

As mentioned during my first calibration, the issue with the new 11-point controls is that they don’t line up 100% with the expected stimulus levels (at least not in dynamic mode) so there’s quite a bit of playing around. The onboard patterns didn’t seem to be correctly lined up either or didn’t respond to calibration controls properly. At least the UB6050’s controls didn’t have this issue. It could be a bug. In any case, use external patterns and going from the top: 11 is meant to be 100% stimulus, 10 is 90% stimulus, 9 is 80% stimulus and so on… at least in SDR!

I would need more time with the unit to figure this out. One way to check the stimulus levels is to do a 30-40 point greyscale and then jack up one colour at a time per stimulus then re-profile greyscale to see where the colour spike occurred. Then repeat with the next stimulus. Again, with more time I could have done this.

Greyscale: this is only serviceable. But the blue push in the low end was better than having a red push higher up affecting skin tones. So this can be tightened up massively using the 11-point greyscale if you don’t mind fiddling around with it. In which case, you should NOT use any offsets and use only gains then work down the 11-point greyscale.

EOTF lined up well (tone mapped from 60% stimulus upwards – this changes per HDR slider setting)

CMS was quite challenging in HDR. I only remembered to take a picture of the gamut after CMS adjustment. I could have made it better with more time, but this is a fine first attempt especially because the gamut is not linear in dynamic at all. But it did improve the picture quite a bit and got rid of the ridiculously oversaturated colours. It is interesting that colour luminance was kind of alright in Dynamic this time, but the saturations were crazy. This is the opposite on the UB6050 / UB5050 / TW9400.

Conclusion

It normally takes me a couple of full days playing with a new display in such a non-linear picture mode to figure out the behaviour and then get the hang of it 100%. It doesn’t help that the controls aren’t yet bug-free in dynamic from what I can tell. Epson did improve HDR gamut and greyscale quite a bit on the UB6050 / 5050 / TW9400 using a firmware update. That unit had a bad red push near black which was difficult to calibrate out with earlier firmware. I would expect Epson to improve on the Dynamic mode this time around as well.

In any case, we enjoyed playing some SDR and HDR content on the Epson after the changes. The laser dimming in dynamic mode is quite aggressive and was fun to see.

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