Mastering Exposure and Skin Tones in Photos with Nobe OmniScope: A Technical Guide to Color Correction

Once In A Lifetime Studio

Summary:

This video demonstrates a step-by-step workflow using Nobe OmniScope for precise exposure and skin tone correction in photos, ensuring consistency across a series of images.

• The presenter highlights OmniScope's benefits as a learning tool for recognizing correct exposure and skin tones, enhancing editing confidence, and ensuring consistency.
• The workflow begins with broad adjustments to exposure and white balance using False Color and Vectorscope.
• Fine-tuning of skin tone is achieved through hue adjustments, aiming for a natural and healthy appearance.
• The Skin Tone scope is then utilized with a gradient overlay to ensure consistency across the entire face and other photos in a series.
• The process normalizes the image to a neutral starting point before any creative color grading is applied.

Introduction to Nobe OmniScope [00:00]

Nobe OmniScope by Time in Pixels is introduced as a secret tool for achieving perfect exposure, consistent skin tones, and overall consistency in photos and videos. This application provides precise feedback based on average skin tones in a technical manner, saving time and eliminating guesswork. It integrates with various editing software like DaVinci Resolve, Premiere Pro, After Effects, Photoshop, and Lightroom, and can be used with any editor via screen capture mode. A demo version is available to follow along.

Benefits of Using OmniScope [00:48]

OmniScope serves as an essential learning tool for photographers and videographers new to color correction and grading.

• Helps in recognizing correct exposure and skin tones.
• Builds confidence in editing decisions.
• Ensures consistency across all media, preparing images for subsequent color grading.

Workflow Outline [01:21]

The demonstrated workflow, using Capture One (but applicable to any photo editor), involves three main steps:

1. Broad Adjustments to Exposure and White Balance: Establishing a solid foundation for the image.
2. Fine-tuning Skin Tone with Hue: Making skin tones appear natural and healthy, normalizing the image to a neutral starting point.
3. Using a Reference Photo for Series Consistency: Applying the perfected edit as a reference for the remaining photos in a series.

Running OmniScope [02:09]

• Launch OmniScope and select "screen capture" mode if not using a supported plugin editor.
• For a single monitor setup, tile windows to keep the photo subject and OmniScope panels visible.
• Enable "Stay on top" under the "View" menu to keep OmniScope in the foreground during editing.

Adding Scopes [02:52]

The workflow utilizes three specific scopes:

1. False Color Scope: Added first and positioned on the left side of the screen.
2. Skin Tone Scope: Placed underneath the False Color scope.
3. Vectorscope: Positioned on the right side.

• Panel proportions can be adjusted, and the layout saved for future use.

Basic Scope Settings [04:00]

• False Color Scope:
  • Right-click and select "Presets".
  • Choose the "ATOS" preset, popular among videographers and photographers.
• Vectorscope:
  • Stock settings are sufficient for this workflow.
• Skin Tone Scope:
  • Right-click and choose "Settings".
  • Set the "Model" to "HSL" for intuitive view changes, as opposed to YCbCr for broadcast standards.

Setting Exposure with False Color [05:12]

The False Color scope functions like a weather heat map:

• Interpretation: Red areas indicate overexposed elements, dark blue indicates underexposed elements.
• Target Values (ATOS preset, under good lighting):
  • Lighter Skin Tones: Aim for peach and light gray (60-70 IR) on the face.
  • Highlights: Can reach yellow (around 80 IR).
  • Brown Skin: Adjust values about 10 IR lower than for lighter skin.
  • Very Dark Skin: Adjust values about 20 IR lower.
  • General Rule: Highlights should not exceed 80 IR.
• IR (Institute of Radio Engineers): A unit of measure for video signal strength, used here to measure exposure.
• Reference: If unsure, search for similar photos with good exposure to use as a visual guide.

  

Adjusting White Balance with Vectorscope [06:34]

• Add a white balance layer in your editor.
• Use white balance and tint controls to bring colors closer to what was seen during capture.
• White Balance Picker Tool: Click on a neutral white element in the photo (e.g., whites of eyes, paper, white shirt).
• Vectorscope Interpretation for Skin Tone:
  • Zooming Method: Zoom into a well-lit, non-blown-out part of the skin to observe the scope pattern.
  • Selection Method: Hover over False Color or Skin Tone scopes, click and drag to highlight a well-lit part of the face.
  • Skin Tone Line (I-line/Flesh Tone Line): Look for a gradual skin-colored pattern near this line on the Vectorscope.
    • It points towards red due to hemoglobin's natural reddish undertone in skin.
    • Patterns near the center indicate less saturation, while patterns near the edge indicate greater saturation.
    • This line is applicable under white/neutral light conditions (within 10-20 degrees).
• Preliminary Adjustment: Aim to get the skin tone selection near the skin tone line using white balance and tint, acknowledging that exact alignment isn't always possible due to natural skin variations.

  

Adjusting Hue with Vectorscope [10:09]

• If the skin tone alignment is close but slightly off after white balance, apply a hue shift as a layer in your editor.
• Effect of Hue Shift: Adjusting the hue slider will cause the pattern in the Vectorscope to rotate clockwise or counter-clockwise.
• Fine-tuning: Make small changes and zoom out to check the broader context of the image.
• Troubleshooting: If the skin target is significantly off, consider picking a new white balance point and repeating steps.
• Contaminated Ambient Light: Use a color wheel to find the opposite color (e.g., bluish-teal for orange light) and apply it to offset color casts.

Using Skin Tone Scope and Settings [11:29]

Once the skin tone is set, use the Skin Tone scope to double-check and achieve consistency across other photos.

• Fine-tuning Settings: Right-click on the Skin Tone scope and select "Settings."
• Hue Bounds: The sliders below the model (default 0.42 upper, 0.7 lower) adjust the skin tone selection. Experiment with these based on image exposure and lighting.
• Overlay Mode (Gradient 3):
  • The dropdown offers "Grid," "Solid Color," "Gradient 2," "Gradient 3," and "Color 3."
  • "Gradient 3" is recommended for its ability to accurately recognize skin tone variations, especially with makeup, and track changes across similar faces in a series.
• RGB Color Matrix: For custom RGB values to change gradient colors, otherwise leave it default.
• Isolating Skin Selection (Saturation & Luminosity Limits):
  • Top Saturation Slider (High-pass): Excludes less saturated parts. Slide right to exclude non-skin elements.
  • Lower Saturation Slider (Low-pass): Excludes highly saturated parts. Slide left to exclude non-skin elements.
  • Top Luminosity Slider (High-pass): Excludes darkest parts. Slide right to clean darker regions.
  • Bottom Luminosity Slider (Low-pass): Excludes lightest parts. Usually fine for well-lit images, but adjust if skin tones are exposed differently.
  • Experimentation is key to finding optimal settings.
• Additional Features:
  • Gray Background: Grays out non-selected tones.
  • Apply Mask: Globally isolates the selection by concealing the rest of the image.
  • Transparency: Adjusts overlay opacity.
  • Low-pass: Applies a filter to smooth out high-frequency information and noisy edges in the selection.
• Interpreting the Skin Mapping (HSL Model):
  • Aim for a green to yellowish map that uniformly covers the skin with Gradient 3.
  • Too yellowish/red: Shift hue towards green.
  • Too green/disappearing: Shift hue towards red.
• Alternative Models: Try "Gradient 2" or change the model to "YCbCr" for a different perspective; the mapping color will change.
• Crucial Note: Pay attention to the picture itself and do not rely entirely on the scopes.

  

Applying Edit to Other Photos [16:55]

• Once the first photo is adjusted, copy and paste the adjustments to the rest of the photos in the series.
• Preview each photo with OmniScope and use the outlined workflow to quickly and accurately match exposure and skin tones across the entire series.
• This workflow is similar for video editing.
• Practice: Regularly search for reference photos (brightly and dimly lit) from professional photographers and use OmniScope to compare and train yourself to recognize target exposure and hue for different skin tones. This practice will boost confidence and improve content quality.