Optimizing the i1 Display Pro OEM for Lightspace

Actually I’m enough of a nerd to find all the detail background fascinating and would have listened to the whole thing in one half hour go without blinking … well, not ‘literally’ of course. Still, waiting for the final episode of this serialized matinee show to be able to actually do the whole thing … 😉

🙂

Well – we also have a rule on Mixing Light… each Insight is a single thought. Part 2 of optimizing for an i1 Display Pro OEM is actually a 2nd thought, so it’s a natural break point. Part 2 will be out in a few days, you won’t have to wait long.

Hello, Patrick!

I have a question – how do you connect i1 Display Pro OEM to computer? Just via usb? I have a PC, 64 bit, Windows 7 and all my Davinci station placed on PC. So I plugged 1 Display Pro OEM to my computer, but nothing happened. And when I press “measure” button I see than I am running virtual probe. What am I doing wrong?

I have a JVC DTV24-L1D monitor that connected via blackmagic converter

With LightSpace CMS there is no requirement to install any drivers for the i1 Display Pro – all that is included with LightSpace.
But, you do have to select the i1 Display Pro via ‘Discoverable Probes’.

Installing the i1 Profiler software can cause issues – so is best avoided!

Steve

Thanks Steve.

Based on Steve’s comments – be sure you’ve watched the earlier videos in this series, since these optimizations assume you already understand how to use Lightspace: https://mixinglight.com/portfolio/getting-started-with-lightspace-dps-part-1/

Steve thank you very much! That exact step I missed! And now when I I chose my device via discoverable probes, it works!

Not sure why you are trying to use a gamma of 2.4 for Rec 709. It should still remain 2.2 for Rec 709. Steve Shaw goes into great detail about using a gamma of 2.2 and not 2.4 in this thread: http://www.liftgammagain.com/forum/index.php?threads/help-with-calibrating-a-new-resolve-suite.6109/

The discussion is a bit more nuanced….

First the discussion about what grade 1 CRTs were actually doing has been going on for years with the consensus of ‘some where between 2.2 and 2.5 ! ‘ 🙂

Next, gamma is not explicitly stated with any Rec. 709 documentation or recommendation. But adoption of BT. 1886 tried to address that (but strangely 1886 doesn’t address a lot of other important things!)

The BT. 1886 EOTF is an attempt to tackle the gamma ‘problem’ head on and mathematically compensate for the issue of a Power Law Gamma curve i.e. 2.2, 2.4 etc being based on absolute black that few displays can do.

In other words, BT. 1886 takes into account the black performance of the display which results in smooth steps out of black and less black clipping on a typical display compared to using power law gamma.

BT. 1886 is an actual standard (good) but its not without is detractors. Many are of the opinion that on some displays a BT. 1886 curve can look less than good (shadow bump) and because 1886 is essentially variable based on the performance of the display, it might not the best choice for professional mastering displays

The reason I mention 1886 in this context is because you ask about 2.4.

Really the question should be why was Pat not using BT. 1886 (a standard) vs a Power Law curve (2.4 in this case)

The interesting thing is because an OLED (as Patrick is using) can display absolute black, BT. 1886 and a Power Law 2.4 Gamma Curve actually become the same thing (assuming native OLED black level)!

But as Steve points out native black level on OLED can be a perceptual & translatable issue for a colorist (especially in a less than ideal reference environment) with blacks. So what a lot of people will do when calibrating an OLED is use black level limiting for the 3D LUT or as many people do, use the brightness knob on the display to bump on black to .03 -.05 (or there about) This alters the overall average gamma at bit but this is a preferential thing – I know many people who leave their OLEDs set to 0.

Also don’t forget that viewing environment is lost in all of this (see HLG EOTF)

To that end a little light reading from Mr. Poynton

http://www.spectracal.com/Documents/3_Gamma_2.0_2.2or2.4.pdf

What Robbie said!

Plus I’ll add and emphasize… Rec 709 does NOT specify a display gamma. Not. At. All. That said, you’ll find that different cities have different ‘standards’ that they seem to have adopted. And over the past 10 years, the gamma ‘standard’ has changed for many markets.

Even the BBC has changed. For a long time they recommended using 2.35, which their testing showed was closest to the Sony BVM series of Class 1 reference displays. But then about 18 months ago they switched to 2.4, since they noticed most of the post houses and broadcasters were monitoring with 2.4… so they kind’a kicked the can and said, “2.4 it is”.

I don’t think I remember anyone really using 2.2 for their reference displays for broadcast work – except for a short period a few years ago when post facilities were deciding between 2.2 and 2.4. Most of our peers have settled on 2.4 for broadcast and 2.2 for web.

But when it comes to Profiling and Calibration – if your display has a selectable Gamma, you just want to be reading in the same mode that your display is in (which is usually the gamma mode you’re generally working in)… as the various gamma functions tend to be mathematically derived from the underlying calibration LUT.

Finally – you’d think display viewing would be ‘settled science’. It’s NOT! Half of the science of viewing televisions is about human perception… which is hugely variable. There are lots of very smart people who argue the finer details of all these points, And they fall all over the spectrum of what is ‘proper’ and ‘accurate’. As working pros, we need to evaluate the various opinions and then settle on our own approach.

What I’m teaching is what I’ve settled on – in consultation with Robbie and Dan Moran – to present to you.