Adjust color values in FCheck

Note: As of Maya 2020, FCheck is no longer supported on macOS. You can select a different default image viewer in the Applications preferences (Windows > Settings/Preferences > Preferences).
Tip: The luminance, saturation, gamma, offset, animation speed control, bump gain, and bump color keyboard keys can be used with Shift, Alt and Ctrl keys. Hold down Shift, Alt or Ctrl keys while pressing the function key to increase the variations. Shift = 10%, Alt = 50%, and Ctrl resets the value.

For more information and a full description of these keys, see Image adjustment keys.

Adjusting luminance

Luminance is the intensity of glowing or reflective light on a given image. The range of luminance settings in FCheck is between -100 and +100. Use the following keys to increase and decrease the luminance:

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Increasing luminance causes images to glow brighter.
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Decreasing luminance causes images to dim.

Adjusting saturation

Saturation is the amount of color vibrance in the image. The range of saturation settings in FCheck is between -100 and +100. Use the following keys to increase and decrease saturation:

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Increasing saturation increases the shine of the color tones in the image by taking existing colors in the image and adding more of the same colors. The more saturated the image, the more it looks like a child’s color painting.
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Decreasing saturation increases the amount of black and white tones in the image. When an image is totally desaturated (-100), the image appears in black and white.

Adjusting gamma

Gamma is the overall brightness of an image. Changes to gamma not only adjusts the brightness, but also adjusts ratios of colors in the image. The range of gamma settings in FCheck is between -100 and +100. Use the following keys to increase and decrease gamma:

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Increasing gamma will make the image brighter and paler. A “bleached out” effect occurs.
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Decreasing gamma darkens the color tones in an image. Overall brightness is also decreased.

A specific gamma value can also be entered by typing fcheck -G <gamma> into the command prompt and opening an image/sequence. <gamma> represents the gamma value wanted.

Note: Images have an initial gamma value, but sometimes it is not the one you want. Programs such as Matador change the gamma value in RLA files because Matador writes a 2.2 gamma while storing the image in gamma 1.0 and the image looks washed out when you display it using FCheck or a compositing software.

By supplying the correct gamma value using the -G option on the command line, you can display the image as intended. This is one of the most useful command line options in FCheck acting as a gamma repair tool.