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This chapter is from the book

This chapter is from the book

The ColorCorrect Node

ColorCorrect combines Add, Mult, Gamma, ContrastRGB, ColorReplace, Invert, Reorder, and Lookup all into one node, giving you the ability to tune the image in only the shadow, midtone, or highlight areas. ColorCorrect will also give your clients all of the needed controls to endlessly noodle with your shots. Not to worry, you are charging by the hour, remember?

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  1. Select File > New Script and answer No when prompted to save your script.
  2. FileIn the hiker.iff clip from the Lesson03 folder.
  3. Attach a ColorCorrect node from the Color tab.

Color Correct Subtabs

The ColorCorrect node is organized into the following seven subtabs:

Subtab

Description

Master

applies the correction to the entire image

Low Controls

applies the correction primarily to the darkest portion of the image, with the correction falling off as the image gets brighter

Mid Controls

applies the correction primarily to the middle range of the image

High Controls

applies the correction primarily to the highlights of the image, with falloff as the image gets darker

Curves

applies manual correction to the image using curves

Misc

performs secondary color correction, as well as invert, reorder, and premultiplication control

Range Curves

displays the different image ranges (shadows, midtones, highlights), their control curves, and the final concatenated curve of the color correction

The Master, Low, Mid, and High Controls Tabs

The first four tabs are identical except for the portion of the image that they allow you to modify. Each has controls to Add, multiply (Gain), and apply a Gamma to the RGB channels, as well as apply contrast on a per-channel basis (Contrast, Center, and SoftClip).

At the bottom of the tab is a display toggle to switch the channels from RGB display to a different color space model. You can modify it to display RGB, HSV, HLS, CMY, or TMV (Temperature/Magenta-Cyan/Value).

  1. Click on the button at the bottom marked HSV.

    The numbers are converted to HSV space.

  2. Switch back to RGB mode by clicking on the RGB button.

    Each Color Picker has an AutoKey and View Curves button associated with all three channels for that parameter. All three channels are treated equally.

Working with Low/Mid/High Ranges

Here is the difference when working with Low, Mid, and High. This is the original image:

  1. Click on the Mid Controls tab in the ColorCorrect1 node.
  2. Adjust the Blue Gain to 1.5.

    Blue is only added to the midtones of the image, which are the areas of the sky and snow.

  3. Select the High Controls tab.
  4. Adjust the Blue Gain to a value of .75.

    Only the highlights of this image are adjusted, which makes the clouds a warm yellow color. You can also control the range of the image's shadows, midtones, and highlights by going to the Range Curves tab.

  5. Select the Range Curves tab.

    This tab displays your final color correction, as well as the Low, Mid, and High mask ranges, as curves. You can also use the display toggle to switch the output from the normal, corrected image to a display of the Low areas, the Mid areas, or the High areas. A colored display was used rather than one based on luminance since different channels will have different values.

  6. Click on the ViewL, ViewM, and ViewH buttons.
  7. To control the mask areas, turn off the Color display and turn on the Ranges display at the bottom of the Range Curves tab.

    Here are the curves for the low, mid, and high values. These curves can be modified by adjusting the low and high parameters.

  8. Right-click on the Parameters workspace and select Reset All Values.

Curves Tab

The Curves tab allows you to apply manual modifications to the lookup curve by mapping input colors to output colors.

  1. Click on the Curves tab.
  2. Turn on the bExpr radio button on the right side of the parameter.
  3. Insert some new knots (or points) by Shift-clicking on a segment of the curve and dragging the newly created points to correct the image.

    Color correcting using curves can yield results that are hard to duplicate with any other method.

Misc Tab

  1. Select File > New Script and answer No when prompted to save your script.
  2. FileIn the flowers.iff clip from the Lesson03 folder.
  3. Attach the flowers.iff clip to a ColorCorrect node.
  4. Click on the Misc tab.

    This Misc tab has several functions in it:

    • Invert— Inverts the red, green, and blue channels.

    • reorderChannels— By entering a string, you can swap or remove your channels as per the standard Reorder method.

    • preMultiplied— Toggle this on if your image is premultiplied (typically, an image coming from a computer-generated render), and it will automatically insert an MDiv before the calculations and an MMult afterwards.

    • Color Replace— This is the same as the ColorReplace node located in the Color tab. It allows you to isolate a color according to its hue, saturation, and value, and replace it with a different color. Other areas of the spectrum will remain unchanged. This is especially handy for spill suppression when performing keying operations.

    Next, you will isolate the red flowers and change their color.

  5. Click on the Source Color Picker.
  6. Select one of the red flowers in the Viewer.
  7. Now click on the Destination Color Picker and drag the Color Picker to a blue color.

    The flowers have only partially turned blue. If you adjust some of the Range/Falloff parameters, you can get it just right.

  8. Adjust the hueRange to a value of 0 and satRange to a value of .5.

    The flowers should now look completely blue.

  9. Quit Shake.
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