CMYK Adjust

This how-to is about applying CMYK correction to specific color ranges using the CMYK Adjust effect.

Color Correction is an important process when dealing with footage that was shot with different equipment or in different lighting conditions. See also the how-to about white balance. CMYK Adjust is an interesting filter for some special tasks in color correction.

Naturally, digital video footage uses the RGB color space. But CMYK Adjust in addition has parameters (or sliders) for Cyans, Magentas, Yellows, and Whites, Neutrals and Blacks.

The effect works by changing the color intensity (or saturation) of the color individually with the respective slider - all the other colors are not affected. For example, you can increase or decrease the intensity (or saturation) of the color red using the slider Reds without changing other pixels (i.e. those parts of the image that are not red). Most important is that neutral color tones remain unchanged. So this effect/filter is very useful for reducing redishness in skin tones.

Using the Whites slider you can make bright color tones more redish (move the color tone more toward red-magenta) or blueish (move the color tone more towards blue-cyan). The same applies for Neutrals to change the mid-tones and Blacks for the dark tones.

The effect works like a mask for a specific color tone but limited to one of the six basic colors. The advantage is that you do not have to create a precise selection and that you can directly change the intensity (saturation).

Attention

When moving the Reds, Yellows or Magentas slider to the right (increases the value) the intensity (saturation) decreases; moving it to the left (decreasing the value) increases the intensity (saturation). All other sliders work as one might expect: higher values increase intensity (saturation). *[RGB]: Red Green Blue *[VFX]: Visual Effects *[feathering]: Smoothing or blurring the edges of a feature *[LFO]: Low-Frequency Oscillation *[dB]: decibel *[LUFS]: Loudness Units Full Scale *[AI]: Artificial Intelligence *[LLM]: Large Language Model *[HSV]: Hue, Saturation, Value *[SOP/Sat]: S(lope), O(ffset), P(ower) / SATuration *[CDL]: Color Decision List *[HSL]: Hue, Saturation, Lightness - Using HSL color space is useful for subtle color changes *[px]: pixel *[hh:mm:ss:ff]: hours:minutes:seconds:frames *[Hz]: Hertz *[CIE]: Commission internationale de l'éclairage, French for International Commission on Illumination *[DCI]: Digital Cinema Initiative *[nadir]: direction pointing directly below a particular location *[OS]: Operating System *[decibel]: Unit of measurement (dB) for sound levels *[clipping]: A form of distortion that limits a signal once it exceeds a threshold *[Spectrogram]: Visual representation of the spectrum of frequencies of a signal as it varies with time *[prevent clipping]: Dynamic range compression (DRC)is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, thus reducing or compressing an audio signal's dynamic range. *[SNR]: Signal-to-Noise Ratio *[dbFS]: Decibels relative to full scale *[QHD]: Quad-HD *[UHD]: Ultra High Definition *[XML]: Extensible Markup Language *[fps]: frames per second