Scope IRE in relationship to Monitor IRE

[preditorj40153117]

I may just not know what i am looking at but....
Does it make a difference what the IRE of a screen is versus the default IRE of the scopes in Premiere? OR 
Is the difference negligible or somehow not a factor.

BenQ 10bit monitor in Rec709 calibrated

[R Neil Haugen · Accepted solution]

Of course, "nits" is now the standard term. The scopes still have an "IRE" scale, but think "nits". Which is what we calibrate monitors to.

IF your monitor is video sRGB, calibrated to white point of D65, Rec.709, gamma 2.4, and 100 nits ... and the calibration is actually accurate ... then the scopes scale and the monitor (in a moderately dimmed viewing environment) should be pretty accurate. Of course, the Lumetri scopes should be set to Rec.709.

The scopes scales are ... "editor style" ... I suppose. The IRE scales on the left side are straight-forward. But the right side scale looks like Premiere is running in 8 bit and full/data range, as the numbers show 0-100 in most forms of the RGB and Waveform. Which ... isn't actually the case. Think of those as more a percentage figure or a monitor mapping number, where the output will be mapped to 0-100 on the screen.

To see the actual data numbers, the Waveform in YC/no chroma mode gives you a right-side scale of 16-235, normal "video range" which is of course proper for most video signals. The internal processing is all 32 bit float, taken directly from the bit-depth of the original clip through Lumetri at 32-bit float into the bit-depth of the chosen format/codec at export.

So ... if you're using 10-bit media, the displayed numbers of the right side scale of the Waveform YC/no-chroma "stand" for 64-940.

I'm running a BenQ PD2720U, calibrated with the i1 Display Pro puck/Software, but ... trust but verify, right?

I also run a pairing of Lightspace and Resolve with my puck to generate a profile, and when the charts tell me I'm good, then I believe it. I've to a deltaE below 2.1 for a "max" point, just one small area in the dark blues (still well below visual potential) and everywhere else below 1.8. Gamma curve near perfent, 99.8 nits. White point within a point.

I'm comfortable ... but of course, Steve Shaw over at LightIllusions.com that makes Lightspace (and prints a TON of good white-papers on pro video calibration processes and gear) ... along with most colorists ... will simply say if you're not running a break-out card to get the signal out of the OS without the OS messing with it, and into either a LUT box or a monitor with internal LUT storage ... calibrated and profiled with either Lightspace or Calman ... well ... you ain't sure what you got now are you?

I don't do any broadcast, and I've had some of my outputs checked on full on systems ... and I'm comfortable with it.

Neil

[preditorj40153117]

Its a paid calibration by a colorist. my monitor does hold luts and profiles. I remember him setting my custom profile. 
You definitely answered my question. I was looking at the scope values and wondering why they didn't follow my monitor. 

This really cleared that up for me. It's a clearer description of the values.
Thank You. 

"">>> IF your monitor is video sRGB, calibrated to white point of D65, Rec.709, gamma 2.4, and 100 nits ... and the calibration is actually accurate ... then the scopes scale and the monitor (in a moderately dimmed viewing environment) should be pretty accurate. Of course, the Lumetri scopes should be set to Rec.709.

The scopes scales are ... "editor style" ... I suppose. The IRE scales on the left side are straight-forward. But the right side scale looks like Premiere is running in 8 bit and full/data range, as the numbers show 0-100 in most forms of the RGB and Waveform. Which ... isn't actually the case. Think of those as more a percentage figure or a monitor mapping number, where the output will be mapped to 0-100 on the screen.

To see the actual data numbers, the Waveform in YC/no chroma mode gives you a right-side scale of 16-235, normal "video range" which is of course proper for most video signals. The internal processing is all 32 bit float, taken directly from the bit-depth of the original clip through Lumetri at 32-bit float into the bit-depth of the chosen format/codec at export.  <<<""

[R Neil Haugen]

Ahh, which BenQ do you have?

I've got a PD2720U, but ... it don't hold LUTs  ... sigh ...

Neil

[preditorj40153117]

You are right. It only has the internal 3d lut (loadable) and 2 custom settings. 

PD3200Q