Final Cut Pro: Color Grade Log Video Without Using a LUT

Shooting log video is a great way to preserve highlight and shadow detail in an image. However, it requires color grading to make the image look its best. (Native log footage looks washed out and gray.)

The easiest way to start color grading is to apply a LUT. However, in some cases, LUTs may not be known or available.

The good news is that log video is, in almost all cases, shot with accurate color, but inaccurate grayscale – and fixing gray scale values is easy.

EXTRA READING

• Here’s a tutorial that explains the difference between the terms HDR, RAW, Log, LUT & 10-bit Media.
• Here’s a short video that explains how to color grade Log video using a LUT.

To display the video scopes, open Final Cut and type Cmd + 7. This toggles the video scopes on or off.

NOTE: If you need more screen room, type Control + Cmd + 1 to toggle the Browser on or off.

UNDERSTANDING THE WAVEFORM MONITOR

The Waveform Monitor is the key video scope to making Log video look good. The Waveform Monitor tells us everything we need to know about the grayscale values in an image. (The Vectorscope tells us everything we need to know about color.)

Grayscale values are divided into three sections:

• Shadows (0 – 33%). These make an image feel “richer.”
• Mid-tones (33 – 66%).This adjusts the emotion and/or time of day in an image.
• Highlights (66 – 100%). These give an image its energy. .

IMPORTANT: For SDR video, shadow levels MUST NOT go below 0%. Highlight levels MUST NOT go above 100%. Mid-tones can go anywhere that looks good to you.

If your Waveform monitor does not look like the image above, click the small icon in the top right corner of the scope (top red arrow), choose Waveform (bottom red arrow), then choose Luma.

GET STARTED

Here’s a video clip shot in Log. Let’s pretend we don’t know what camera shot this. As you can see from the Waveform Monitor (the scope on the right), all the grayscale values are concentrated in the middle.

NOTE: When adjusting Log video, you can ignore the Vectorscope, displayed on the left.

Since we don’t need to worry about color – as the Log footage is color-accurate – we can concentrate our attention on the Waveform Monitor.

TO ADJUST A CLIP

• Select the timeline clip you want to adjust.

• If you are using Final Cut Pro 10.6.6 or later, open the Video Inspector (Cmd + 4) and scroll toward the bottom. Make sure Color Conform is set to Automatic.

• At the top of the Inspector, click the Color Inspector (top red arrow).
• From the menu, select Color Wheels (bottom red arrow).

A color wheel has three controls:

• Grayscale slider (right arrow)
• Saturation slider (left arrow)
• Color hue (middle arrow)

To color grade LUTs we only need to adjust the grayscale slider. Raising the slider makes a specific grayscale range brighter. Lowering it makes the range darker.

NOTE: If you don’t see all four color wheels, click the View menu in the top right corner of the video scopes and select All Wheels.

• The four color wheels control the three grayscale ranges – shadows, mid-tones and highlights – as well as a Global control.We make adjustments to shadows first, highlights second and mid-tones third.

THE CORRECTION PROCESS

Adjusting grayscale values for SDR (Standard Dynamic Range) media is a four step process:

1. Select the clip
2. Adjust the shadows grayscale slider until the darkest part of an image sits at or near 0%. (If there’s no true black in the image, set this around 5%.)
3. Adjust the highlights grayscale slider so the brightest part of the image is at 100%.
4. Adjust the midtones grayscale slider until the rest of the image looks good to your eye. There’s no “perfect” setting, only what looks “good” to you.

To show you how this works, this is the starting image. Notice that the waveform monitor displays a thin range of pixel values, the image is very gray, and the grayscale sliders for all four wheels are set in the middle.

Making the adjustments outlined above – which takes about ten seconds – we have the grayscale-corrected clip.

• The shadows are sitting exactly at 0%. (The Shadows sliders was moved down dramatically.)
• The highlights are sitting exactly at 100%. (The Highlights slider was moved up dramatically.)
• The midtones were adjusted until the image looked “right.” Unlike shadows and highlights, there are no rules on where mid-tone settings need to go.

REPLICATING THE EFFECT

Once you understand how the color wheels work, color grading Log video is easy. After the first clip looks the way you want:

• Select the timeline clip that has the corrections.
• Choose Edit > Copy
• Select all the other timeline clips that need adjustment
• Choose Edit > Paste Attributes and select the color settings to apply to all the selected clips.

Done.

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