Color Controls and Grading Modes

Color correcting live signals and reference media is done in the grade controls area of the main window.

Grade controls are grouped in grading nodes, a grading node can be understood as one image filter with one or more parameters. A certain set of grading nodes belong to a grading mode. A grading mode is a color pipeline for a certain purpose or tailored to a certain hardware device (e.g. “CDL and LUT”, or “ACES CDL”).

Grade controls

 

Grading modes and grade controls

The grade controls consist of the following elements:

  • Grading node: Grouping element containing the actual grade controls
  • Node enabling: Enable or disable the effect of a grading node
  • Look name: The name of the currently applied look
  • Grading mode selector: Switch between the different grading modes available on the drop down menu
  • Edit node structure: Some grading nodes can have variable grading nodes, you can add and reorder grading nodes in the edit mode.
  • Look actions: The look action menu contains actions for interacting with looks stored in the shot library.
  • Control panels: The control panels button and indicator shows the attached grading panel. You can disable / lock the attached grading panel to prevent unwanted changes.
  • Clear buttons: Clear either all grading nodes (“Neutral”) or just the creative color manipulation nodes (e.g. CDL node) and not LUTs or tone mapping curves (Reset Colors)
  • Filter configuration: Temporarily bypass creative color manipulation nodes, or show the original signal with no filtering at all, or enable the false color mode.
  • Result curve: The video scopes shows the resulting curves for all enabled grading nodes in the three RGB channels.

Grading Modes

The application supports different grading modes designed for specific camera setups and workflow environments.

The node-based design allows you to disable and reorder individual filter nodes to have greater grading freedom. You can disable a certain node by unchecking the blue check box. Have in mind that the processing order is from «top to bottom» when reordering the nodes.

Each mode allows different levels of grade customization, as the compatibility of the grades down the workflow creates some restrictions on how the color information has to be processed. For example, the camera compatible grading modes can have the nodes locked in a certain position to ensure the compatibility of the grade when being uploaded into the camera.

The available grading modes are:

  • CDL and LUT: More information in the article Using the CDL Grade mode.
  • CDL Advanced: Allows you to add and reorder multiple nodes on advanced workflows.
  • ACES CDL: A mode adapted to the ACES standard. More information in the article Using the ACES grading mode.
  • ACES CDL Advanced: A mode adapted to the ACES standard. Allows you to add and reorder multiple nodes on advanced workflows.
  • Alexa Looks (Deprecated): This mode is designed to create .xml ALEXA Looks compatible with ARRI ALEXA cameras. More information in the article Using the ALEXA Looks grading mode.
  • Amira Compatible: This mode is designed to create .aml AMIRA Looks compatible with ARRI AMIRA cameras.
  • ARRI CAP Compatible: This mode is designed to interact with an ARRI camera via the CAP protocol. See Setting up ARRI Cameras for more information.
  • Varicam Compatible: This mode is designed to create 3D LUTs and looks compatible with Panasonic Varicam cameras. See Setting up Panasonic Varicam for more information.
  • Freestyle: This grading mode has been created to allow complete grading freedom. For this reason, there are some limitations on the available export formats for looks created on this mode.
  • Freestyle ACES: This grading mode has been created to allow complete grading freedom for ACES based workflows.

Node Editing

Some grading modes allow you to reorder, add and delete filter nodes. To start customizing the grading nodes, you have to click on «Edit».

Once you are in the «Edit» mode, it is possible to reorder the nodes using drag and drop. You can remove a node by clicking on the «x» button. The «+» button allows you to add new filter nodes to the grading mode.

In order to maximize the compatibility of the grades along the production workflow, as well as the ability to export the grades in a certain format, there are some limitations on how you can reorder the grading nodes. The Freestyle modes do not have these limitations, but you can only export those looks as 3D LUTs and not as CDL files. These are the limitations:

Nodes Reordering Default Nodes Export Options
CDL and LUT (not editable) 1CDL, 1Sat, 1LUT3D (not editable), CDL + Sat + LUT3D CDL + Sat + LUT3D ASC-CDL, 3D LUT
CDL Advanced xCDL, xSat, xLUT1D, xLUT3D, x2ndary (not editable), CDL + Sat + LUT3D CDL + CDL + Sat + LUT3D ASC-CDL, 3D LUT
ACES CDL (not editable) 1IDT, 1CDL, 1Sat, 1ODT (no edit) IDT + CDL + Sat + ODT ASC-CDL, 3D LUT
ACES CDL Advanced 1IDT, xCDL, xSat, xLUT1D, xLUT3D, x2ndary, 1ODT xCDL + xSat (All CDL nodes together, all saturation nodes together), IDT before ODT, ASC-CDL, 3D LUT
Alexa Look (deprecated) Alexa Look has fixed nodes Alexa Look has fixed nodes 3D LUT, Alexa Look (deprecated)
Amira Compatible xCDL, xSat, xLUT1D, xLUT3D, x2ndary, xLUT3D xCDL + xSat (All CDL nodes together, all saturation nodes together), nothing before xCDL+xSat ASC-CDL, 3D LUT, ALF-2
ARRI CAP Compatible xCDL, xSat, xLUT1D, xLUT3D, x2ndary, xLUT3D xCDL + xSat (All CDL nodes together, all saturation nodes together), nothing before xCDL+xSat ASC-CDL, 3D LUT, ALF-2
Varicam Compatible xCDL, xSat, xLUT1D, xLUT3D, x2ndary, xLUT3D xCDL + xSat (All CDL nodes together, all saturation nodes together), nothing before xCDL+xSat CDL, Sat, LUT3D ASC-CDL, 3D LUT
Colorfront Film 1CFEIn, xCDL, xSat, 1CFELook, 1CFEOut CFE
Freestyle xCDL, xSat, xLUT1D, xLUT3D, x2ndary 3D LUT
ACES Freestyle 1IDT/1ODT, xCDL, xSat, xLUT1D, xLUT3D, x2ndary IDT before ODT 3D LUT

ReplacedForPFDStart[]

* xCDL, xSat, where «x» means multiple nodes.

Available Grading Nodes

CDL Node

The CDL node holds controls for the slope, offset, and power (SOP) values of the ASC-CDL formula.

The CDL node has several interaction types with different controls for different interaction styles. The interaction types of one CDL node all work on the same set of CDL values, so changing controls in one interaction type might change control positions also in the other interaction types.

The available interaction types:

CDL interaction type:

CDL node – CDL interaction type

The CDL interaction type allows to manipulate the nine values of the SOP triples (for each color channel R, G, B) of the CDL. The values in the nine text fields are the same values as in an exported ASC-CDL file.

The color wheels have a global control (in the bottom left of each wheel), an indicator around the ring shows if the global control is modified. Changing the wheel control doesn’t change the gloabl luma of that control, e.g. the channels are balanced and the global control doesn’t change by changing the wheel position.

Lift, Gamma, Gain (LGG) interaction type:

CDL node – LGG interaction type

The LGG interaction type allows to manipulate lift, gamma, and gain (LGG) values as known from other grading systems. These control values are mapped to CDL values in the background. The nine text fields show lift, gamma, and gain values (not ASC-CDL values) – switch back to the CDL interaction type to see the CDL values of a certain setting of LGG values.

The color wheels have a global control (in the bottom left of each wheel), an indicator around the ring shows if the global control is modified. Changing the wheel control doesn’t change the global luma of that control, e.g. the channels are balanced and the global control doesn’t change by changing the wheel position.

Simplified (SPL) interaction type:

CDL node – SPL interaction type

The SPL interaction type allows to manipulate the values of the CDL filter with the controls Contrast, Stretch, Warmer and Greener.

Increasing the contrast control makes the resulting curve steeper by clipping black and white. Increasing the stretch control increases contrast in the highlights, while decreasing stretch increases contrast in the shadows. Increasing the warmer control gives the image a warmer appearance by giving the shadows a warmer tint while the whites stay unmodified. Increasing the greener control gives the image a greener appearance by giving the shadows a greener tint while the whites stay unmodified.

Printer Lights (PRT) interaction type:

CDL node – PRT interaction type

The PRT interaction type allows to simulate a color correction based on printer lights. Printer lights can be approximated by an offset in camera log encodings. Additional buttons for each color channel allow for changes in fixed steps.

ASC-CDL files can be directly loaded and saved to/from the CDL node (supported format: *.cdl).  Click the gear button on the left side of the CDL node and select if you want to load or save a CDL.

Please be aware that the ASC-CDL specification always includes a saturation value. When one saturation node is present CDLs will be loaded and saved from/to the present saturation node. When multiple CDL and saturation nodes are present you will be pointed choose the saturation node you want to load the saturation to (indicators A,B,C etc.).

The size of the color wheels can be adjusted in the Preferences menu. Just choose a size that fits your display resolution.

The CDL node can be controlled by an external hardware grading panel. To have more information on how to use it, please check the following articles:

Saturation Node

Just drag the slider to either side to increase or decrease the saturation on your look.

figure : Saturation node

figure 7: Saturation node

3D LUT Node

The 3D LUT node is designed to load your own 3D LUTs by pressing the «Load…» button. Alternatively, you can also use one of the available preset 3D LUTs to convert the image to a Rec.709 color space.

figure 4: 3D LUT node

figure 8: 3D LUT node

Supported formats for loading into the 3D LUT node are:

  • Adobe Speedgrade (.cube; size 32,33, 65)

  • Assimilate Scratch (.3dl; size 32)

  • Panasonic Varicam (.vlt)

  • Autodesk Lustre ( .lut) 

  • Truelight (.cub)

1D LUT Node

The 1D LUT lets you load your own 1D LUT file. Click the “Load…” button and select the 1D LUT you want to load to the node.

figure:

figure 9: 1D LUT Node

In contrast to the curve node the LUT in the 1D LUT node can not be edited afterwards.

Supported formats are:

  • *.txt
    • channels: 3
    • range: 0.0 … 1023.0 (float)
    • header: “R G B – HDLINK GAMMA TABLE”
    • entries: 1024
    • row example: “221.37 221.37 221.37”
  • *.data
    • channels: 4
    • range: 0 … 16383 (integer)
    • entries: 16384
    • row example: 15040,15040,15040,15040
  • *.lut
    • channels: 3 (4 columns with leading index (0…65535, R, G, B)
    • range: 0 … 65535 (integer)
    • header: “LUT16”
    • entries: 65536
    • row example: 45490 58366 58366 58366

Curve Node

 

figure : Curve node

figure 10: Curve node

The Curve node lets you adjust the 1D LUT curve on the image. If you click on «Edit», the curve editor window will pop up. It allows you to precisely grade your footage:

  • To add a point just click on the curve, and in order to modify it’s value just drag and drop.
  • To remove a point simply move it out of the curve editor’s window.
  • When you move your mouse over the curve editor, the graph shows you the value of the exact point where it is.
Figure 1. CDL curve editor

figure 11: Curve editor window

 

HHS Node

The HHS node –Hue to Hue and Saturation– is a new kind of node that allows you to map a certain hue on the image and replace it by another color with different hue and saturation. Here is an example where the red has been desaturated, but the other colors remain the same:

HHS comparison

The HHS editor allows you to drag and drop the hue circles to another location on the color space to replace the original color with another one.

figure 5: HHS editor

figure 12: HHS editor

 

Grading modes with custom color pipelines

The ACES grading modes have special grading nodes representing the specific transforms of the ACES pipeline, e.g. IDT and ODTs. You can learn more about these grading modes in the article Using the ACES CDL Grading Mode.

The Colorfront Film grading mode that’s used with AJA FS-HDR (Module only) has specific transforms, e.g. CFE In and CFE Look.  You can learn more about these grading modes in the article Using the Colorfront Film Grading Mode.

Linked Looks

You may have noticed that on the right side of each node in the grading panel a chain symbol appeared. It indicates the synchronization state of the node:

  • Blue chain button: Node is synced between linked slot (indicated with a red frame)
  • Grey chain button: Node is unsynced between linked slots and therefore controlled independently (indicated with a grey frame) 

It’s possible to switch the linked state of a node by clicking on the chain buttons. For more detailed information about the node synchronization, please check the article Linked Looks.