There are a few options for workflows when converting from raw/log to rec709.
Our primary cameras are Red + Alexa.
Approach 1: LUTs
About:
A LUT (LookUp Table) uses a set of numbers to match Input Values from the camera to Output Values to achieve a desired look, in this case, converting to Rec.709
Upsides:
- Easy to use, works like a preset.
- Includes automatic tone mapping which helps preserve some of the values from the much larger color space of the camera when converting it to the smaller space of Rec.709.
Downsides:
- Less control
- A LUT compresses the Input Color Space to fit inside Rec.709, values that are clipped will not be recoverable after the LUT. This is not true for the other approaches in this guide.
Steps:
In the Color Tab:
- Create a node with which to apply the LUT
- Right click the node > LUTS > 3D LUTS > browse to the LUT you need based on your source camera
- For ARRI footage, LUT is “ARRI Alexa LogC to Rec709“
- For RED footage, LUT is ?
Approach 2: Color Management > Color Space Transform
About:
This method involves using Resolve Project settings to tell Resolve to transform all clips in your project from an Input Color Space/Gamma to an Output Color Space/Gamma.
Unlike LUTs, this transform does not compress the footage’s original range into Rec709’s, but rather matches values from one space to another. As a result it is easier for highlights to appear blown out compared to using a LUT, however these highlights are not actually clipped and the information from the source footage can be pulled back with adjustments.
Upsides:
- Values from the original color space are not clipped.
- The conversion to Rec.709 is done for all the footage in your project, you don’t need to set for each clip individually
Downsides:
- More steps than a LUT.
- Will appear to have blown out highlights without applying Tone Mapping
- The conversion is happens before the grade – you lose the ability to grade in log in the Color Tab.
- It converts all the footage in your project using a single Input setting, and therefore will not work for a multiple camera project with multiple Input Color Spaces/Gammas.
Steps:
In Project Settings > Color Management > Color Space & Transforms
- Color Science: DaVinci YRGB Color Managed
- Check Use Separate Color Space and Gamma to get a clearer sense of what the following is doing
- Input Color Space: Set based on camera/footage
- Timeline Color Space, Gamma: Rec.709, Rec.709
- Output Color Space, Gamma: Rec.709, Rec.709
- Limit Output Gamut To: Output Color Space
- Timeline to Output Tone Mapping (adds Tone Mapping to roll off blown out highlights)
- Method: Simple – This applies a S-shaped contrast curve. This gets you the closest in appearance to using the LUT
- Method: Luminance – This results in nicer roll off of highlights
- Max Timeline Luminance – Leave at 100 for standard dynamic range delivery
- Timeline to Output Gamut Mapping:
- Method: Saturation Mapping
- “Saturation Knee” is the threshold above which “Saturation Max” will start to affect the saturation
The above settings are what should be used to achieve the same results as the Color Space Transform OFX. There is some confusion about why “Rec.709” should be set for gamma instead of “Gamma 2.4“, which might require further research.
Here is some insight: http://www.bmcuser.com/forum/post-production/davinci-resolve/24300-final-explanation-of-gamma-and-color-shift-problems
Approach 3: Resolve OpenFX > Color Space Transform
About:
This approach works the same way as Approach 2 (Resolve is using the same math to transform the color space), but is set as an effect on a node in the Color tab.
Upsides:
- All the advantages of Color Space Transform as described in Approach 2,
- Added benefit that you can grade with log controls before the Transform node.
Downsides:
- More steps than a LUT.
- Will appear to have blown out highlights without applying Tone Mapping
Steps:
In the Color Tab:
Find the Color Space Transform OFX effect in your OpenFX library and apply it to desired node
In Color Space Transform settings:
- Input Color Space: Select based on your camera/footage
- Input Gamma: Select based on your camera/footage
- Output Color Space: Rec709
- Output Gamma: Rec709
Enable Tone Mapping:
Example with Arri Alexa Log Footage:
Approach 3: ACES
ACES is a color management system that unifies footage from different cameras to a single color space. This allows you to convert footage from multiple cameras to Rec709, and to grade that footage in a unified, cohesive way. The color space also has the added benefit of responding to exposure adjustments in a way much closer to how film responds to exposure changes in camera, and can allow you to push light and color intensities further.
Upsides:
- Unifies multiple camera formats
- Filmic response
- Can push color and light intensities further
Using ACES in Color Management:
This method converts all your footage to Rec709 while also placing them in ACES Color Space. So while your footage will look Rec709, the adjustments you then make in the color tab will take advantage of ACES’s color and exposure response.
In Project Settings > Color Management:
- Color Science: ACEScc
- ACES version: ACES 1.1 or latest
- ACES Input Device Transform: No Input Transform (will be set later or automatically)
- ACES Output Device Transform: Rec.709
- Process Node LUTS in: What’s this?
In Color tab:
The ACES Input Transform will be set automatically for Camera Raw footage, but for footage that is log or Rec.709 this will need to be set manually by right clicking a clip and navigating to ACES Input Transform, then selecting the relevant camera or color space.
Using ACES Transform OFX
Similar to the Color Space Transform effect, there is an effect called ACES Transform you can apply to a node. To use this method to convert to Rec709 while also being able to grade in the ACES color space you’ll want to:
Create one ACES Transform Node to convert from source color space to ACEScc
- ACES Version: Aces 1.1 or latest
- Input Transform: Set according to your camera/ footage
- Output Transform: ACEScc
Create a second ACES Transform Node to convert from ACEScc to Rec709
- ACES Version: Aces 1.1 or latest
- Input Transform: ACEScc
- Output Transform: Rec709
You can now make grading adjustments in ACES color space between these two Transform nodes.
Note: In doing tests, it is apparent that this method produces very very similar but not identical results to setting Project>Color Management settings to ACES…
This post also reports and discusses the discrepancy https://acescentral.com/t/discrepancies-using-a-pseudo-aces-workflow-in-davinci-resolve-via-aces-transform-ofx-plugin/1696
Aces in Fusion
Converting footage to ACES in Fusion requires you to download the config used for the OCIO ColorSpace node
- OCIO Config: Browse to the location of your downloaded config
- Source Space: Select according to your camera/footage
- Output Space: Rec.709
Note: A comparison shows that this produces identical results to setting ACES in Project Settings > Color Management for color grading
Working with Red + Alexa Footage
Across the above tools, where there are settings for input color space and input gamma, they should be set as follows for Arri and Red cameras
Arri:
Input Color Space: ARRI Alexa
Input Gamma: ARRI Log C
Red:
Input Color Space: DRAGONcolor2
Input Gamma: REDlogFilm
Note: These are the settings Blaine told me a while back for footage from his camera. Not sure if we will use RED cameras of a different model from is?