IPP2 / LUT matching issue

[Tim Sessler]

Hi guys -

I recently shot a short on my HELIUM, built a LUT specifically for the project and was super pumped by the look. It looked great during the shoot and proxies really reflected the look.

Now going into grade, I am having a tough time replicating this look. For some reason color, contrast and highlights are not matching at all.

Here are some examples:

Shot #1 - Still from proxy (ProRes 422 LT):

Shot #1 Still from R3D in RESOLVE:

Comparison of the two:

Shot #2 - Still from proxy (ProRes 422 LT):

Shot #2 Still from R3D in RESOLVE:

Comparison of the two:

As far as workflow I have two nodes in Resolve.
Node #1 for desaturation and creative LUT
Node #2 for IPP2 LUT

As far as R3D settings everything is kept untouched from the metadata:

I tried different Contrast and Highlight-Rolloffs just to be certain that this wasn't the culprit. But I am just not able to replicate the look that the proxies were giving us in terms of basic color and contrast.
Where is this severe difference coming from? I am sure there is some degradation with the proxies happening - but this seems to be more. Colors hues are different in highlights and shadows if you compare the two - highlights are warmer in R3D, while the shadows still retain a warmness in the proxy (not a even color balance shift or tint shift).

I really love the new IPP2 workflow - but this has been a headache and not being able to keep a consistent look makes this a lot more difficult than I thought it would be.

Let me know if you have any ideas on how to solve this and how I could achieve the same look that I had in the proxies.

Thanks!
Tim

 

[rand thompson]

Tim,

I always had to "duplex" the color grade and the IPP2 transform into one hybrid Lut to get the colors to look as I graded them especially when bringing in luts you create outside of the Ipp2 workflow, for example 3DLut creator. Could you include a .r3d frame of the image, plus, export the grade as a lut out of davince without the Ipp2 tranform in the last node. I can try a hybrid lut in 3dlut creator with your grade and the Ipp2 tranform combined.

 

[rand thompson]

Tim also,


You can import the image with the grade in Redcine-X and save it as a "look" .rmd file. If you have luts that are specifically designed to work with Ipp2 transforms, like Phil holland's Philmcolor Lut or which replace or include an Ipp2 tranform like Chris McKechnie's luts or Hrvoje Simic's luts, the colors will look correct. If you don't the colors won't look correct if you combine it with an Ipp2 transform.

 

[Tim Sessler]

Interesting! Meaning you create a LUT that includes both the IPP2 transform as well as the creative LUT in one LUT?

I included both a look only LUT, as well as 3 versions that include IPP2 with different highlight rolloffs: https://www.dropbox.com/sh/xijl2khzbfk311e/AACR59FqkZBg6NOLtmyTZwR6a?dl=0

Let me know if you need anything else - and thanks so much for the help!!

Tim

 

[rand thompson]

Tim,


Here is your original Prores Proxy image compared against the "Hybrid"(medium/medium ipp2 transform and your grade "Duplexed" into one Lut) They still don't match however. I'm still trying to find out why. The Hybrid Lut included the Medium/Medium IPP2 output transform and your .cube Lut of your grade. I made the same Camera raw settings but something is still off, I think its with how your grade from I assume in-camera is being translated in resolve. There's probably some setting that has no equal setting in resolve to translate it correctly. Also, was this a Rec709/gamma 2.4(bt1886) project or something different?


Hybrid Lut

https://www.dropbox.com/s/v93yy6syr31acy4/Hybrid.cube?dl=0


Original ProRes 422 Proxy

Hybrid Plus 4800 temp and -3.00 tint in Camera Raw

Original ProRes 422 Proxy

Hybrid Plus 4800 temp and -3.00 tint in Camera Raw

 

[Tim Sessler]

Hm.... this does look a lot closer though! I wonder we actually changed the contrast or highlight rolloff for the exterior shots.

How did you create the Duplexed LUT? Did you pull those stills from RCX or Resolve?

Thanks a ton for this help. I really appreciate it!!

Cheers,
Tim

 

[rand thompson]

Tim,


You're welcome! I still don't think the problem has been completely resolved, let me know if you want to try something else. I imported the stills from you dropbox link into resolve so that I could see how closely the "Hybrids" matched and exported all from resolve. I'm sure other programs can do this but I use 3DLut Creator Pro.

 

[Tim Sessler]

Thanks, I'll give that a try and make some more hybrid LUTs to see if that gets me closer.

If you have a second check out this R3D: https://www.dropbox.com/sh/urimizpa01wxuwa/AAAwAt4gjJ8n58-4ijZRmdF8a?dl=0

Colors are not even close. The LUT was created in Resolve - it just seems weird that camera and Resolve would interpret it differently.
I'll keep trying to solve this. Thanks so much for all the help thus far!!!

 

[rand thompson]

Tim,

When making Luts in Resolve, make sure you "only" use "primary" corrections, any corrections other than those won't translate properly in a .cube file. Checking the lut above now.

 

[rand thompson]

Tim,


Do you have your camera's latest firmware? what version Ipp2 Luts are you using? Also, you might want to check the settings of the look you created in-camera against your settings in Resolve to double check if everything is corresponding correctly. Here's an alternate grade and .rmd Look file for the clip above if you are interested.


Grade in Redcine-X

https://www.dropbox.com/s/275gczpje4cp1db/interior grade redo.RMD?dl=0



More conventional S-curve


https://www.dropbox.com/s/kzggrils9mxd2df/conven S-Curve.RMD?dl=0

 

[Aaron Lochert]

Your proxy:
A006_C010_02085D_001.mov.19_38_44_23.Still001 by Aaron Lochert, on Flickr

Your R3D in Resolve:
default_1.8.1 Resolve_Hybrid_LUT by Aaron Lochert, on Flickr

My R3D in Resolve:
interior_1.7.1 by Aaron Lochert, on Flickr

I didn't use the hybrid LUT, I just used the "without IPP2" LUT and then the RED IPP2 Medium/Medium LUT after. Seems like it matches to me.

However, for the exteriors, those don't match up for me. You sure you used the same LUT outdoors? Or perhaps there were some CDL settings in camera that got baked into the proxy as well?

 

[rand thompson]

Aaron,

I looked back in Resolve and I think I chose the Resolve version from Tim's post instead of the original Proxy for the exterior " comparison image" , my mistake! Yeah , I used the " without IPP2 Lut" cube file and duplexed that with the medium/medium ipp2 output transform to create the Hybrid Lut. The hybrid Lut was only meant for the exterior scene.

 

[rand thompson]

Aaron,


Did'nt pay attention to see who the post was from, thought it was Tim, or to whom it was addresses to, again, my bad.

 

[rand thompson]

Tim,


your "Crow" grade with "skin" emphasis In Resolve.

No Crow grades

 

[Marc Wielage]

What happens if you just throw the LUTs out and just color correct in Resolve?

I think IPP2 is a good concept and it can work very well in color sessions. But I don't get being wedded to LUTs, for the simple reason that lighting changes too much. Speaking just for my way of working, I also tend to color correct different parts of the frame differently, and LUTs can't do that. Eyes, faces, left side of the frame, right side of the frames, skies, floors... sometimes it's useful to treat each of these areas differently.

Also, what display are you using and how was it calibrated? There's always the risk (particularly with some kinds of LCD displays) where the monitor could be emphasizing some problems, obscuring others, and not actually telling you the truth about the image.

 

[Tim Sessler]

While I would absolutely agree with you, its kind of besides the point, isn't it? Most of the time the LUT is only for reference but sometimes there are projects that only tweak an existing look slightly and actually rely on the look that was created for the project.
Same with the monitor. The monitor could be completely out of whack - looking at the same image and same color, two shots should still match, regardless if they are accurate or not.

But back to the starting point of all of this- I was just wondering about: Camera + LUT = Look A (Proxy) vs. R3D + LUT ≠ Look A

Anyways... appreciate all the input so far!! Thanks everybody!!

 

[Eric Haase]

While I would absolutely agree with you, its kind of besides the point, isn't it? Most of the time the LUT is only for reference but sometimes there are projects that only tweak an existing look slightly and actually rely on the look that was created for the project.
Same with the monitor. The monitor could be completely out of whack - looking at the same image and same color, two shots should still match, regardless if they are accurate or not.

But back to the starting point of all of this- I was just wondering about: Camera + LUT = Look A (Proxy) vs. R3D + LUT ≠ Look A

Anyways... appreciate all the input so far!! Thanks everybody!!

Three things to try to narrow it down....

1. I don't think the CDL settings in camera will affect the image in Resolve. One example of this is when using IPP2 in camera, if you change the SATURATION parameter it will get baked in to your proxies but when you load the R3D in Resolve, the parameter will have no affect and is nowhere to be found when using the IPP2 workflow you are using. You can test this with an extreme example by just making the saturation zero in camera and then bringing the file in. Resolve's IPP2 implementation is really confusing and incomplete. I am not sure if this is part of the issue you are having (maybe there is a CDL or like setting changed in camera that Resolve cannot read)?

2. When you apply a LUT in camera, is the creative LUT applied before or after the IPP2 Output transform? I am not sure it is actually applied before the IPP2 Output transform as we would hope but I haven't tested it.

3. I believe the camera interprets 3D LUTs tetrahedrally. Make sure you have selected this option instead of Trilinear in Resolve Color Management. Trilinear is the default BTW.

 

[Tim Sessler]

Three things to try to narrow it down....

1. I don't think the CDL settings in camera will affect the image in Resolve. One example of this is when using IPP2 in camera, if you change the SATURATION parameter it will get baked in to your proxies but when you load the R3D in Resolve, the parameter will have no affect and is nowhere to be found when using the IPP2 workflow you are using. You can test this with an extreme example by just making the saturation zero in camera and then bringing the file in. Resolve's IPP2 implementation is really confusing and incomplete. I am not sure if this is part of the issue you are having (maybe there is a CDL or like setting changed in camera that Resolve cannot read)?

2. When you apply a LUT in camera, is the creative LUT applied before or after the IPP2 Output transform? I am not sure it is actually applied before the IPP2 Output transform as we would hope but I haven't tested it.

3. I believe the camera interprets 3D LUTs tetrahedrally. Make sure you have selected this option instead of Trilinear in Resolve Color Management. Trilinear is the default BTW.

All really great points! Will test it out.

Thanks!!

 

[andrew wehde]

Three things to try to narrow it down....

1. I don't think the CDL settings in camera will affect the image in Resolve. One example of this is when using IPP2 in camera, if you change the SATURATION parameter it will get baked in to your proxies but when you load the R3D in Resolve, the parameter will have no affect and is nowhere to be found when using the IPP2 workflow you are using. You can test this with an extreme example by just making the saturation zero in camera and then bringing the file in. Resolve's IPP2 implementation is really confusing and incomplete. I am not sure if this is part of the issue you are having (maybe there is a CDL or like setting changed in camera that Resolve cannot read)?

2. When you apply a LUT in camera, is the creative LUT applied before or after the IPP2 Output transform? I am not sure it is actually applied before the IPP2 Output transform as we would hope but I haven't tested it.

3. I believe the camera interprets 3D LUTs tetrahedrally. Make sure you have selected this option instead of Trilinear in Resolve Color Management. Trilinear is the default BTW.

I ran into these same issues and found in resolve, to apply the creative lut to the first node and then the 2nd node apply the ipp2 lut. the footage then matched the R3D file with the creative lut applied.