Color's Red Tab crushes highlights

[Damien Molineaux]

What's up with the Red Tab in Color ? When comparing my scopes with the Red Tab activated (with a number of different settings), and when it is deactivated ; my whites are getting compressed/crushed.

What's up with that ?
Cheers,
Damien

 

[Patrick Tresch]

Tu veux dire que tu ne peux pas dépasser la valeur de 100% contrairement à d'autres codecs comme Prores? Si c'est ça c'est normal...

Bonne soirée

Pat

Just for the non Romand... I said him that you can't go higher in values than 100% when grading with R3D wich is not the case if you import Prores files for example in the same color timeline. Even if the broadcast safe is turned off. ;-) But I don't know if this was his point...

 

[Sean Rawls]

I haven't experienced this before . . . so I can verify the the "Red tab" does function. I think Patrick is saying to check if you have Broadcast safe enabled (forgotten most of my French from 5th grade). Anyways, check that and also make sure your Red QT codec and FCP installer and are up to date.

Good luck,

 

[Uli Plank]

No, the "Broadcast Safe" switch doesn't change that, it's the implementation of R3D in Color – never goes beyond 100. Just make sure to pull down ISO/exposure in the RED tab until you don't miss anything in your highlights, then grade to your liking.

Non, je ne veux pas traduire, pardonnez moi.

 

[David Battistella]

Also,

What color space and gamma space are you working in? Redspace can definitely clip the highlights.

David

 

[Kaku Ito]

Also,

What color space and gamma space are you working in? Redspace can definitely clip the highlights.

David

I was gonna say that, too. I believe this is the case. I think the default in Color is "REDSPACE". Switch that to REC709 (most likely) the copy all in the beginning of the grading session.

 

[Damien Molineaux]

I was gonna say that, too. I believe this is the case. I think the default in Color is "REDSPACE". Switch that to REC709 (most likely) the copy all in the beginning of the grading session.

Hi, thankyou for all your feedback.

I'm not talking about not being able to go over 100%. No, whatever the settings for gamma and colorspace (or ISO) the parts of my image exposed over 50% are pushed up towards the 100% limit. It is very clear on the waveform. I guess it applies some kind of curve, and strangley if you uncheck the Red Tab, you get more latitude in your highlights, however you loose the benefit of a number of options available in the Red Tab.

Cheers,
Damien

 

[Ben Brainerd]

I did some playing around with a project I'm working on this afternoon, as I've seen the whole "Turning off the RED tab" thing before.

I was originally going to say that turning off the RED tab shows you the Linear Light version of the footage, but that's obviously not the case. It turns out that having the RED tab off gives you something close to (But not exactly) a PDLOG 685 output. Or REDLog at about ISO 160 (At least for the clip I'm playing with.

Working with RED footage in color definitely requires you to know what each of the various settings does. Particularly the Gamma settings. Both REDSpace and Rec.709 do, in fact, basically apply a curve as you theorized. There's a bit more going on under the hood, but that's a good general way to look at it.

The point I just discovered is that the clipped data is *unrecoverable*, which I find interesting. And kinda annoying. So if you take a clip and jack the ISO up to 2000, your highlights are GONE. Doesn't matter how much you pull down the gain.

Knowing that, it's fairly simple to work around. Got a couple of options:
1) Prep all your footage. When you bring it into Color, check your settings, then check all the clips for that scene and set the ISO/Color/Gamma to keep anything from clipping.

2) Use one of the LOG gamma spaces. You'll have to pull the image out to more realistic levels, as you can't use Color's Log-to-Lin tools on non-DPX footage. Or build yourself a LUT.

Ok, so I've obviously been doing Colorist work a bit too long if I can call those "Simple" with a straight face.

 

[Kaku Ito]

In case you have hard light, I found that by turning up the ISO because the skintone is too dark, will crash all of the details in highs.

What you can do is to keep the ISO as 320, turning the gamma space as 709, jack up the master gamma pretty high, the use the luma curve to darken the lows.

The dark area gets little bit noisier but the all of the possible highend could be all preserved as much as possible.

 

[Monty Bass]

Does anybody use Camera RGB and Redlog?

Seems like everybody just modifies Rec. 709 and Redspace.

 

[Ben Brainerd]

In my case, I use Camera RGB and Rec.709 as my baseline. Using the LOG settings *in* Color doesn't seem to make sense. It adds a lot more time to my workflow for negligible results. Without a decent LUT for the LOG footage, which I have yet to find/make, it's not worth it.

Now, if I'm working with DPX, LOG's the only way to go.