REDLogFILM > Rec.709 LUT - Anyone have one? Made one? Graeme?

[Sidney L. Plaut]

Unless Pablo works for Red, it's not gonna cut it.

I would very much like an official white paper from RED about working w RedlogFilm in a professional environment, meaning where you have several post houses collaborating, and using
official LUTS (like we do with Arri and Sony...).

Redlogfilm LUT's should be available either as download on RED.com or be provided by RED to the relevant software companies, so you have
the official LUT's that can be selected.

For feature work or High end commercials, where post takes place immediately and in several countries at the same time - It is not a solution having well meaning redusers making their LUTS... and sharing them...
and NO you don't have the time to work out a pipeline for each job for each post house.... which is why "official" is the key word.

 

[Nick Shaw]

I would very much like an official white paper from RED about working w RedlogFilm in a professional environment, meaning where you have several post houses collaborating, and using
official LUTS (like we do with Arri and Sony...).

I would say that for any post house familiar with log workflows a white paper should not be necessary. REDlogfilm uses exactly the log curve defined by Cineon, and implemented in software such as Nuke. As an example Nuke's standard log2lin node linearises REDlogfilm perfectly.

As for log to video LUTs, that is very much an aesthetic choice. There is no "correct" log to video LUT.

If you like the way REDgamma (1, 2 or 3) looks you can work with the LUTs I sell on my website, which will convert REDlogFilm to match the appearance of any of the REDgamma curves (except that my curves are scaled to map sensor black to video black, unlike the pure REDgamma curves which leave the blacks raised so the user can sit them down using "shadow" or other SDK controls.)

 

[Brett Harrison]

Honestly, a LogC to Video LUT made using Arri's tool is going to be very, very close, to the point where anyone who isn't an experienced colorist is going to see a very satisfying result. I do, and I AM an experienced colorist. Just make sure you build the LUT without a color matrix (in other words, LogC to Video, Extended range on both source and destination, and NO color matrix). The mistake many people make is choosing the Rec709 color matrix in the Arri tool. This is appropriate for Alexa material, but not needed or wanted for Red material, which already has a color matrix applied (that's what Redcolor1/2/3 is).

So if RedLogFilm implements the Cineon standard, and you're able to apply a color transform matrix to RLF, does that mean that the Cineon standard is only a gamma transformation, and not a color decode thing?

If so, shouldn't an Arri LogC2Video LUT be a generic LogC2Video LUT (i.e. no color matrix option selected)?

Isn't REC709 a video format? So what is -2Video as distinct from -2Rec709?

What would it mean to have a RLF to Rec709 LUT from RED when RED has said that RLF is an accurate implementation of the Cineon standard? I.e. why not just use the standard one?

Wouldn't changing the color decode option (Redgamma 1 vs 2 for example) mess with the accuracy of a 709 LUT applied to RLF?

 

[Brett Harrison]

If you like the way REDgamma (1, 2 or 3) looks you can work with the LUTs I sell on my website, which will convert REDlogFilm to match the appearance of any of the REDgamma curves (except that my curves are scaled to map sensor black to video black, unlike the pure REDgamma curves which leave the blacks raised so the user can sit them down using "shadow" or other SDK controls.)

Nick, why would you chose to apply a RedGamma LUT to RLF when you can opt for the Redgamma curve in the R3D SDK?

 

[Sidney L. Plaut]

I would say that for any post house familiar with log workflows a white paper should not be necessary. REDlogfilm uses exactly the log curve defined by Cineon, and implemented in software such as Nuke. As an example Nuke's standard log2lin node linearises REDlogfilm perfectly.

As for log to video LUTs, that is very much an aesthetic choice. There is no "correct" log to video LUT.

If you like the way REDgamma (1, 2 or 3) looks you can work with the LUTs I sell on my website, which will convert REDlogFilm to match the appearance of any of the REDgamma curves (except that my curves are scaled to map sensor black to video black, unlike the pure REDgamma curves which leave the blacks raised so the user can sit them down using "shadow" or other SDK controls.)

Nick I am already a happy customer of yours and have had post houses buy your LUT for use on my films - BUT if there is not correct log to video LUT - why A: does Arri and sony have one B: why does'nt Red then at least provide
Redgamma2/3 as an integrated 1D or 3D LUT for resolve etc... so you still be in RLF but grade using the redgamma LUT's?

And no insult intended when I say this, it is a little weird saying to a post pipeline meeting the only way to do the above is to use your LUTS (which thankfully we can), when Arri has a LUT generator and integrated LUT in resolve and now even FCPX....

A quick solution is if RED could give you an official Stamp and sell your LUTS through their website.

 

[M Most]

So if RedLogFilm implements the Cineon standard, and you're able to apply a color transform matrix to RLF, does that mean that the Cineon standard is only a gamma transformation, and not a color decode thing?

Yes.

If so, shouldn't an Arri LogC2Video LUT be a generic LogC2Video LUT (i.e. no color matrix option selected)?

You can build one with or without a color matrix, as I explained earlier. But if you specify "Arri Alexa", that implies a specific camera, with a specific log curve, and specific colorimetry for which that matrix was developed. A color matrix is always camera specific because cameras have different response curves, different color filters, and different internal processing, even when you're recording Raw. That's why you have those matrices available in the Arri LUT builder, and it's why you have Redcolor 1, 2, and 3 available in your R3D decode settings.

What would it mean to have a RLF to Rec709 LUT from RED when RED has said that RLF is an accurate implementation of the Cineon standard? I.e. why not just use the standard one?

Rec709 implies a color gamut and a gamma curve, a very specific one. Cineon defines a very specific log curve. So if you have a "standard" Cineon to Video LUT, it will work fine with RedlogFilm material. The thing is, there are many different implementations of "log", almost as many as there are cameras. The Cineon curve was not developed for digital cameras - indeed, there weren't any when the standard was defined. It is defined in terms of film print density, and because of that, it is not always optimal for retaining values delivered by digital capture devices, which see the world in terms of linear light (as opposed to the logarithmic response of film negative, which defined the Cineon design). Cineon was designed for film scanners, not cameras. Having said that, it IS a known standard, and that alone has a number of advantages. Red - I think wisely, and with the help and support of a very major DI provider - decided to develop a Cineon compliant curve so that DI facilities could use existing color science and transforms to get better results in a predictable way. RedlogFilm wasn't really designed as a "capture" curve, but a translation of already captured Raw information into an easily understood, used, and supported form. That's why you don't have to jump through hoops to transform the images into common color spaces.

 

[Martin Stevens]

I love this tread. Thank you gentlemen.

 

[Nick Shaw]

Nick, why would you chose to apply a RedGamma LUT to RLF when you can opt for the Redgamma curve in the R3D SDK?

So you can grade in log while seeing REDgamma3. That way the highlight compression is applied after the grade, not before.

Isn't REC709 a video format? So what is -2Video as distinct from -2Rec709?

When people talk about a -2video LUT that normally implies a tone-map curve is applied, which compresses highlights and shadows, whereas the pure -Rec709 curve does not compress highlights, and will therefore clip hard in normal (no float) implementations.

…if there is not correct log to video LUT - why A: does Arri and sony have one

The LUTs ARRI and Sony provide are not "correct", they are their own idea of a curve which makes the image from their camera look pleasing, just like REDgamma3 is what RED thinks makes RED footage look pleasing.

And no insult intended when I say this, it is a little weird saying to a post pipeline meeting the only way to do the above is to use your LUTS (which thankfully we can), when Arri has a LUT generator and integrated LUT in resolve and now even FCPX....

No offence taken!

My LUTs are not the only way to do it. As pointed out elsewhere in this thread you can use an ALEXA LUT with no matrix, or create your own curve, either following the look of REDgamma3, or whatever other look you like.

 

[Gunleik Groven]

So you can grade in log while seeing REDgamma3. That way the highlight compression is applied after the grade, not before.

Signalchain...

 

[Sidney L. Plaut]

So you can grade in log while seeing REDgamma3. That way the highlight compression is applied after the grade, not before.


When people talk about a -2video LUT that normally implies a tone-map curve is applied, which compresses highlights and shadows, whereas the pure -Rec709 curve does not compress highlights, and will therefore clip hard in normal (no float) implementations.


The LUTs ARRI and Sony provide are not "correct", they are their own idea of a curve which makes the image from their camera look pleasing, just like REDgamma3 is what RED thinks makes RED footage look pleasing.


No offence taken!

My LUTs are not the only way to do it. As pointed out elsewhere in this thread you can use an ALEXA LUT with no matrix, or create your own curve, either following the look of REDgamma3, or whatever other look you like.

Well Arri LUTs are "correct" in terms of it is official from Arri and most here in Scandinavia at least, use the Arri LUT because it matches what the DP' see on set and expose after....

Its all fine that RED thinks Redgamma3 looks pleasing, but then why don't they provide a .Cube or whatever standard LUT formats grading and compositing software require.

The fact that there are several Redgamma's also kindda goes against the statement that to go from RLF to Rec709 you just use a standard Cineon conversion... Because that will NOT give you the red gamma 2/3 that you
exposed after on set?... I give up. At least you, Nick, provides a solution and I hope you make some money on it, so you can keep providing similar solutions in the future...

Its not that hard to understand why I still havn't met a grading facility that says - shot on Epic ? great! we love it! Its a struggle every time... first you struggle to try shoot Epic, then to stay in RAW, then theres the whole LUT thing... and Down sample algorithms...
Alexa... not so complicated for them....

 

[Pablo Moreno]

I don't understand why you guys want a RLF-->Rec709 LUT,

Picture this for a second:

-On Windows, I right click my R3d on my desktop and I click "open with", I choose Photoshop CS6.

-The Red Photoshop plug in fires up, I choose RC3--RLF from the drop down window and click OK.

-Photoshop opens up a pop up window and ask me if I want to color manage the document, I say yes and choose: assign REC709.

Now hold your horses right there!... am I in REC709 color space already or not by doing that?

Did Photoshop convert the whole thing to Rec709 already or not???, mmm, confusing..


By the way.. for any reason that I don't understand, Red striped down the other color spaces availables in the older versions of RCX, but I still can see them, when I open my old Photoshop plugin.. ????

 

[Sidney L. Plaut]

Pablo,

Nick explained it perfectly in an earlier post. - we would like to use the full dynamic range, so we grade from that, beneath the rec709 LUT. and the way to that is to grade from RLF and NOT transform/ compress it untill the end of the grading chain.

 

[Shiblon Wixom]

A post house not knowing what to do with redlog files is like a DP that can't use a light meter or understand a histogram, but it does seem to happen a lot these days, I prefer to use node based color separation in Resolve since it gives better and more consistent image results than redcolor3 or the Arri LUT, especially for skin tones, but that's just an opinion. I would much rather have everything in a neutral white-balanced log format prior to final grading because its much easier to match up shots or scenes from different cameras and vfx materials, but its just my preference.

 

[Pablo Moreno]

Pablo,

Nick explained it perfectly in an earlier post. - we would like to use the full dynamic range, so we grade from that, beneath the rec709 LUT. and the way to that is to grade from RLF and NOT transform/ compress it untill the end of the grading chain.

Ok, if that is the case, lets put another graphic example like above:

What if I tell photoshop not to color manage the document..

What I am seeing now is nothing but RC3--RLF on my calibrated screen, right? , and if I want to see how it looks in REC709, all I have to do, is a preview with "proof colors".. I guess, I don't know, just trying this to make sense..

 

[Shane Daly DP]

Where is the advanced settings in preferences?? Can't see it.

Thanks

 

[Sidney L. Plaut]

HI Paolo,

I am not familiar with any films being graded in Photoshop, so maybe the examples you are referring to (however right they may be), are not so relevant in this case.

The only relevant question is why RED does not provide a LUT generating Tool or .cube (or any standard LUT format that can be applied as an output LUT or a separate Node).? - I believe all the arguments for this, has been explained the
all the previous posts.

 

[Pablo Moreno]

Where is the advanced settings in preferences?? Can't see it.

Thanks

I don't know if your question is about Photoshop, but if it is:

Edit--Color settings--->

 

[Pablo Moreno]

HI Paolo,

I am not familiar with any films being graded in Photoshop, so maybe the examples you are referring to (however right they may be), are not so relevant in this case.

The only relevant question is why RED does not provide a LUT generating Tool or .cube (or any standard LUT format that can be applied as an output LUT or a separate Node).? - I believe all the arguments for this, has been explained the
all the previous posts.

I know that.. You can apply the same procedure to any color grading software.. is just an example...

 

[Shane Daly DP]

Thanks, I was referring to an earlier post in this thread about RedCine X advanced preferences. Do you know where they are?!

 

[Mike Lary]

Thanks, I was referring to an earlier post in this thread about RedCine X advanced preferences. Do you know where they are?!

Shane, under Preferences/General there's a check box for 'Show Advanced Controls'. Once you tick that you'll see the full list of color space options in the Look tab.