Grading Controls in Silverstack

User Interface overview

 

figure 1: UI with Grading Controls

figure 1: UI with Grading Controls

The Grading Panel in Silverstack consists of all controls for manipulating the image filtering. The controls are grouped in nodes (such as 3D LUT node, CDL node etc.):

  • Grading mode selector: You can switch between the different grading modes available on the drop down menu.
  • Nodes with grading controls: Here you find all the nodes for a certain grading mode such as CDL color controls, 3D LUT loading node, saturation etc. Each node can be individually disabled by un-marking the blue check box.
  • Clear buttons: You can clear either the entire look or just the color manipulation (and not LUTs or tone mapping curves)
    • Using the «Neutral» button you can reset all settings (color and LUT) to a «neutral» state.
    • Using the «Reset Colors» button you can reset the color settings to a “neutral” state.

 

Grading Modes

Silverstack 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 grading 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.

 

figure 2: The different grading modes to choose from.

figure 2: The different grading modes to choose from.

 

The grading modes allowing the greatest level of customization are the Advanced and Freestyle modes.

CDL and LUT

Figure 1: The CDL and LUT grading mode

Figure 3: The CDL and LUT grading mode

The CDL and LUT grading mode offers ASC-CDL controls for the use in a wide range of workflows. For clips recorded in Log color spaces, Silverstack allows to import 3D LUTs or choose from 3D LUT Presets.

In order to support workflows that apply CDL in log gamma as well as in video gamma, the order of LUT and CDL filters can be changed when using the CDL Advanced grading mode. The CDL and LUT mode can also be used with Rec.709 clips without adding a 3D LUT.

The color controls for the CDL and LUT grading mode consist of:

  • ASC-CDL controls node:
    • RGB Shadows, Mid-tones and Highlights color wheels

      figure 5:

      figure 4: ASC-CDL color wheels

 

  • Saturation slider node

    figure : Saturation node

    figure 5: Saturation node

 

  • Import of 3D LUT node: The CDL and LUT grading mode can import 3D LUTs and CDL files and can export ASC-CDL files.
    • 3D LUT Import options with averaged curve displays for each channel

      figure 4: 3D LUT node

      figure 6: 3D LUT node

 

CDL Advanced

Allows you to add and reorder multiple nodes on advanced workflows.

Alexa Looks

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.

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.

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.

Varicam Compatible

This mode is designed to create 3D LUTs and looks compatible with Panasonic Varicam 35 cameras.

Amira Compatible

This mode is designed to create .aml AMIRA Looks compatible with ARRI AMIRA cameras.

 

Available grading nodes

CDL Node

The CDL node contains a color wheel for Offset, Power and Slope. It can be used to adjust the color on the image.

figure 7: CDL grading node

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.).

Saturation Node

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

figure : Saturation node

figure 8: 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 9: 3D LUT node

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 10: 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 11: 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 12: 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 13: HHS editor

Grading Panel Support

Silverstack supports the use of hardware grading panels for the grading functionalities. The following panels are supported:

  • Tangent Element Tk
  • Tangent Wave
  • Avid Artist Color

Connect the hardware panels to Silverstack to precisely and physically manipulate your grades.