4. Color Correction

The Color Correction module allows users to perform color grading on image-based Clips that were previously imported in TACHYON. Color grading is a process that lets you correct images or create artistic effects by modifying visual parameters.

If you have any experience with professional color grading software, you will notice that the Color Correction module’s interface features a design similar to the one of these well-established products. You will find in TACHYON most of the color grading tools you are accustomed with.

The Color Correction module only works with image-based Clip types: Media, FX Stack, Input, Proxy and Virtual Projector.

1. Open the Color Correction Module

The Color Correction module can be accessed in various ways. You can use the following methods to access the module directly, without having a preselected image-based Clip:

• Select {Show > Color Correction} from TACHYON’s main menu.

• Press [Alt+G].

If an image-based Clip is not selected in the Timeline, the Color Correction module’s UI will be grayed out and will not allow interactions. Once an image-based Clip is selected, the UI will light up and allow interactions.

It is also possible to access the Color Correction module through the Timeline module, while having an image-based Clip selected. The selected Clip will act as the target for the Color Correction module:

1. Select {Show > Timeline} from TACHYON’s main menu or press [Alt+T] to open the Timeline module.

2. Select an image-based Clip by clicking on its entry in the Timeline.

3. Unfold the Color section of the Shared Clip Properties window section.

4. Click on the [Edit Color Corrections] button.

1. Color Correction Parameters

Various parameters can be manipulated to modify the visual appearance of an image-based Clip. These parameters are divided along five different sections, each corresponding to a specific toolset.

• 1. Three-Way Correction Tools

The Three-Way Correction Tools allow you to modify a color’s hue and gain in specific regions of the video signal that are delimited by their luminance.

Shadows refer to the darkest part of the signal, Midtones are delimited by a bell curve at the center of the spectrum, and Highlights refer to the brightest part of the signal.

https://www.provideocoalition.com/wp-content/uploads/content-uploads/AVH/Shadow-Midtone-Hilight.jpg

Inside each of the three sections corresponding to the luminance of the signal, you will find a Color Wheel and a Gain Slider.

The Color Wheel allows you to modify the video signal’s hue. The hue refers to the “pure” color, a color’s dominant wavelength excluding its black and white components.

The Gain Slider allows you to increase or decrease the signal’s intensity. Modulating gain will make the image darker or brighter.

• • 1. Color Grading Using Three-Way Correction Tools

Follow these steps when color grading an image-based Clip:

1. Press [Alt+T] or select {Show > Timeline} to open the Timeline module.

2. Select the image-based Clip designated for color grading by clicking on its entry in the Timeline.

3. Now that an image-based Clip is selected, navigate back to the Color Correction module. A thumbnail of the selected image-based Clip will be loaded in both the Original Preview and Modified Preview windows.

4. Identify the region of the luminance spectrum (Shadows, Midtones or Highlights) where you want to apply the modifications.

5. [Click+Drag] the Color Wheel’s white marker, located in the appropriate section (Shadows, Midtones or Highlights), to select the hue you wish to modify.

6. Adjust the value of the Gain Slider by manipulating it with a [Click+Drag] to increase or decrease the intensity of the selected hue, or you can [Double-click] on the slider to open a text field and enter a desired numeric value.

   • 1. Reset the Color Grading Modifications

• Click on one of the [Reset] buttons to cancel color grading modifications for a specific region of the luminance spectrum.

  1. Brightness and Contrast Tools

The brightness and contrast of the image can be modified by using sliders.

• • 1. Modify Brightness

Modulating the Brightness slider will either increase or decrease the overall lightness of the image. Moving the slider will bring all of the colors in the image closer to pure white or pure black.

• Adjust the value of the Brightness slider by manipulating it with a [Click+Drag], or you can [Double-click] on the slider to open a text field and enter a desired numeric value.

  • 1. Modify Contrast

Modulating the Contrast slider will either increase or decrease the difference between the image’s light and dark content.

• Adjust the value of the Contrast slider by manipulating it with a [Click+Drag], or you can [Double-click] on the slider to open a text field and enter a desired numeric value.

  • 1. Reset Brightness and Contrast Modifications

• Click on the [Reset] button to cancel any modifications to brightness and contrast.

  1. HSL, Gamma and Gain Tools

These tools allow you to modify five different parameters of image-based Clips.

• • 1. Hue

This parameter can be modified through the manipulation of the Hue slider. Tonal modifications to the image’s hue will be applied regardless of luminance.

• Adjust the Hue slider by manipulating it with a [Click+Drag], or you can [Double-click] on the slider to open a text field and enter a desired numeric value.

  • 1. Saturation

Saturation refers to the intensity of the colors in an image. Reducing saturation will result in an image dominated by different shades of gray.

• Adjust the Saturation slider by manipulating it with a [Click+Drag], or you can [Double-click] on the slider to open a text field and enter a desired numeric value.

  • 1. Lightness

Lightness refers to the white component of the image. Increasing lightness will result in a paler image.

• Adjust the Lightness slider by manipulating it with a [Click+Drag], or you can [Double-click] on the slider to open a text field and enter a desired numeric value.

  • 1. Gamma RGB

Gamma refers to a section of the light spectrum in an image, defined by a bell curve centered on the midtones, excluding content that is pure black or pure white. The Red, Green and Blue sliders will increase or decrease their respective color content in the area defined by gamma.

• Adjust the Red, Green or Blue sliders by manipulating them with a [Click+Drag], or you can [Double-click] on the sliders to open text fields and enter desired numeric values.

• • 1. Gain RGB

Gain refers to a section of the light spectrum in an image defined by a slope function where the lowest point is situated in the pure black region of the light spectrum and the highest point is situated in the pure white region. The Red, Green and Blue sliders will increase or decrease their respective color content in the area defined by gain.

• Adjust the Red, Green or Blue sliders by manipulating them with a [Click+Drag], or you can [Double-click] on the sliders to open text fields and enter desired numeric values.

  1. Invert

Invert functions will flip the expression of light and dark content within a specific color channel (red, green or blue).

• • 1. Invert Red Channel

• Click on the [Invert Red] toggle to invert the red channel content.

  • 1. Invert Green Channel

• Click on the [Invert Green] toggle to invert the green channel content.

  • 1. Invert Blue Channel

• Click on the [Invert Blue] toggle to invert the blue channel content.

  1. Levels

Levels adjustments allow the user to modify an image’s tonal range. The Input Levels control how the source tonal content will be mapped in the area defined by the Output Levels.

Adjust Input Levels

By manipulating Input Levels sliders, the user can remap an image’s tonal content (values ranging from pure black to pure white) into a different register.

• Adjust the value of the black Input Level slider and white Input Level slider by manipulating the sliders with a [Click+Drag] to increase or decrease the black and white Input Level thresholds, or you can [Double-click] on the sliders to open text fields and enter desired numeric values.

  • 1. Adjust Levels Automatically

It is also possible to quickly achieve the desired tonal correction through an automated process.

• Click on the [Auto] button.

  • 1. Adjust Output Levels

By manipulating Output Levels sliders, the user can clip the expression of pure black and pure white in the image.

• Adjust the value of the black Output Level slider and white Output Level slider by manipulating the sliders with a [Click+Drag] to increase or decrease the black and white Output Level thresholds, or you can [Double-click] on the sliders to open text fields and enter desired numeric values.

  1. Global Reset

Since many tools can be used simultaneously to modify an image-based Clip’s visual properties, it can be tedious to retrace your steps and reset a specific slider. The Global Reset button will cancel all modifications that were made to the Color Correction parameters.

• Click on the [Reset Color Corrections] button located at the bottom of the Color Correction window to cancel all of the color grading modifications that were previously made.

1. Color Curves

Color Curves allow tonal adjustments through the modification of a graph where the horizontal axis represents the image’s Input Levels and the vertical axis represents its Output Levels.

• • 1. Adjust Color Curves

1. Select the desired option from the Color channel dropdown menu (Red, Green, Blue or RGB).

2. [Click+Drag] the Color Curve in order to create and position a new point in the graph.

3. Add as many points as necessary.

   • 1. Reset Color Curves

• Click on the [Reset] button located above the Color Curves graph window.

1. Color Looks

Modifications to Color parameters can be saved in a Look. A Look is a data structure containing color modification parameters that can be recalled and applied to multiple image-based Clips.

• • 1. Create a New Color Look

Follow these steps to create a new Color Look:

1. Set the desired Color Grading parameters in the Color Correction module’s interface.

2. Click on the in the top right corner of the Color Correction window. This will create a new Color Look based on how the Color Grading parameters are set. A thumbnail corresponding to the new Color Look will appear in a column located to the left of the Color Correction window.

Every Color Look will display the selected image-based Clip, with the corrections applied (except on multi-selection or when a non-valid/rendered file is selected).

• • 1. Create an Empty Color Look

It is possible to create an Empty Color Look linked to the currently selected image-based Clip. Creating additional Empty Color Looks makes it possible to develop alternate Color Correction parameter sets for the same Clip.

• Click on the [+] button located in the top left part of the Color Correction window to create an Empty Color Look.

  • 1. Rename Color Look

• Double-click on the Color Look’s thumbnail to open a text field that will allow you to rename it.

1. Original Preview and Modified Preview

The Original Preview and Modified Preview windows are located at the top of the Color Correction window. The Original Preview window shows the image-based Clip prior to any modification, while the Modified Preview window shows the processed version of the same Clip.

• • 1. Pause Content Playback

• Click on the [pause] toggle located at the top of the Original Preview window to freeze content playback. (Click the toggle again to resume playback.)

1. Apply Color Looks

2. Select one or multiple image-based Clips by clicking on their entries in the Timeline. (The Timeline is located in the Timeline module.)

3. [Drag+Drop] a Color Look thumbnail from the list located at the left of the Color Correction window and move it to the Modified Preview window.

OR

[Right-click] on a Color Look thumbnail from the list located at the left of the Color Correction window to open a contextual menu.

1. Select {Load}. A Confirmation Box will open.

2. Click the [Yes] button to apply the Color Look to the previously selected image-based Clips.

3. Delete Color Looks

4. Select a Color Look by clicking on its thumbnail. You can also perform a multiple selection by using [Shift+Click] on multiple Color Look thumbnails.

5. Press the [Delete] key or [Right-click] on the selected Color Look(s) to open a contextual menu.

6. Select {Delete} from the contextual menu. A Confirmation Box will open.

7. Click the [Yes] button to delete the Color Look.