-
Working in LOG (REDlogfilm) with display LUT in Resolve
Hello again guys,
I’m working on a RED MX project at the moment and it’s the first time I’m working in log (REDlogfilm gamma) with RED files in Resolve. I’m using a REDlogfilm to RedGamma display LUT for the time being (in rec709, until we get our new OLED and get that profiled for a film print LUT).
I’ve got used to the Lift Gamma Gain controls feeling like they’re in mud but I can’t seem to get good qualifications (HSL keys) because all the values are so close in the log image. This applies even after a primary because the log to lin conversion isnt applied until output.
I’m working in log because this is for print and we really dont want a linear rec709 to log conversion at the end. It also seems to give me a bit more latitude for that more filmic look. This is also the recommendation from Evangelos and MotionFX who would be doing our prints and is currently consulting us on our colour pipeline.
Does anyone have any tips for working in log in Resolve?
Also to clarify, I’m working from the R3D files but decoding with REDlogfilm gamma and the other settings are from the camera metadata.
Thanks
Toby
-
12 Replies
-
Anyone?
-
why you are not testing with display lut or input lut for your hls keys?
—
Margus
-
Sort I don’t understand, do you mean I should use an input LUT node (add another source), pull the key and then feed the alpha to another node for grading and then pipe that back with the log image? That sounds pretty complex just to get a good key. Please can you elaborate?
-
You want to go all the way with “flat” images?
If not i would use lut as input lut what makes all in the input look “normal” or on node based lut.
But i’m not sure about your all workflow. I’m going to do some redlogfilm job soon and then i will see.
—
Margus
-
Basically I am working in LOG but monitoring in Linear, via a display LUT, as you would in film. It’s nice with RED (MX) and redlogfilm, its a much smoother falloff in the highlights and blacks and a nicer starting point. The only problem is that the HSL key is being pulled from the log image and such there is little separation between colours.
Apart from liking it, by staying in log space for grading, any conversions at the end (say to rec709 or to P3 via LUTs) will have full range data to work from. Doing a rec709 to log converion or rec709 to P3 conversion isn’t ideal.
See this great post by Evangelos on RedUser;
Does anyone have any advice for this workflow and working in Resolve?
-
One way would be to make some creative use of nodes. One node based approach that would do what you want might involve creating a second source node (right click->Add Source), followed by two serial nodes. On the first serial node, enable a log to video LUT. This will feed a “normalized” image to the second node. Set up your HSL key on the second node. When that’s done, connect the alpha output of the second node to the alpha input of a new serial node on your main source. That means that the node will have the log image, but a key that was created from the normalized image. You might have to invert the key on the node in which you created it, but that should get you what you’re asking for.
-
In rereading the thread I see you’ve already considered that approach. In most cases, I don’t usually have a problem with keys on log images. In fact, they’re often cleaner than those on video images. Some grading systems do an internal log to linear (true linear light, not video gamma, which is what you’re describing as “linear” but really isn’t…..) conversion for both color manipulation and keying, and then do other internal transforms for specific operations, so that the image is internally optimized for the specific operation being applied. Resolve does this when you’re using ACES processing, I don’t know if they do when using YRGB. Perhaps someone from DaVinci can answer that one….
-
Hi Toby,
I’m about to start a similar project – Working with RED R3D files in Resolve. Will be grading on a Sony CRT, but the project may have a film out.
Are you just using the REDGamma and REDLogFilm LUTs built into Resolve (under the RED settings) or are you using a specific LUT in either the input or output LUT section?
If you are using either the input or out LUT section which LUTs are you using?
-
I’m using Redlogfilm in the red settings and a display LUT (cinespace) which is a p3 emulation LUT for my monitor. The LUT is being used in the Color tab for each roll in the ‘track’ section/tab (a serial node with a LUT applied to it), but it could also be selected as a display LUT on the LUT config page.
-
Thanks for the info. Are you using a rec 709 monitor or a P3 capable monitor?
Reply to this Discussion! Login or Sign Up