Local Tone Mapping in DaVinci Resolve: A Comprehensive Guide to Advanced Color Grading

Summary:

This video explains Local Tone Mapping in DaVinci Resolve, an advanced color grading technique that allows precise adjustments to specific tonal areas of an image, similar to how the human eye perceives brightness locally.

Key takeaways include:

Local Tone Mapping separates an image into local exposure areas (low-tone, mid-tone, high-tone) for independent editing [Image 1][Image 2].
Creating masks using the HSL qualifier and bilateral blur (Denoise slider) helps isolate these tonal areas [Image 12][Image 13].
Proper color management using IDT and ODT nodes (ACEScc/ct or DaVinci Wide Gamut Intermediate) is crucial for accurate results [Image 8].
Specific applications, demonstrated with before/after examples and mask visualizations, include:
- Highlight Recovery: Bringing back detail in overexposed areas without flattening mid-tones [Image 36][Image 37][Image 38].
- Shadow Fill Light: Brightening shadows to add detail, akin to using a physical reflector [Image 29][Image 33][Image 34].
- Negative Fill: Darkening shadows to enhance contrast, similar to using black fabric on set [Image 14][Image 20][Image 19].
- Mid-Tone Details: Adding contrast and depth to mid-tones selectively [Image 18].
- Skin Tone Density: Enhancing the "filmic density" of skin tones for a more cinematic look [Image 24][Image 22][Image 27].
- Boosting Light Sources: Making light sources appear brighter without affecting surrounding areas [Image 9].
Common issues like halos can be mitigated by using bilateral blur, less aggressive adjustments, and tools like "Clean Black/White" and "Shrink/Grow" [Image 28].

Intro [00:00] [Image 3]

The video introduces Local Tone Mapping as a powerful, previously "missing" color grading technique on YouTube, capable of adding post-production fill light, recovering highlights, adding three-dimensional depth, boosting light sources, and adding filmic density to skin tones.

What is Local Tone Mapping [00:28]

Local Tone Mapping is a combination of "local" and "tone mapping." [Image 1] [Image 2]

Tone mapping without localization [00:59] refers to global adjustments (exposure, contrast) that affect all pixels uniformly, regardless of whether they are bright or dark due to surface value or exposure.
Local Tone Mapping [01:27] is a technique that breaks down an image into local exposure areas (low-tone, mid-tone, high-tone) and allows independent editing of these areas. This aligns with how the human brain processes images, separating surface brightness from local exposure, as demonstrated by the Adelson's checker shadow illusion. [Image 6]

How to create masks [01:39]

To create a localized tonal area mask for Local Tone Mapping in DaVinci Resolve:

Select the target area [02:10]: Use the HSL qualifier to select the desired tonal range (e.g., shadows or highlights) [Image 12].
Feather the selection [02:29]: Apply ramps to feather the selection and avoid artifacts.
Localize the mask with blur [02:37]:
- A basic Gaussian blur blurs all pixels based on distance, localizing the effect [02:44].
- A Bilateral Blur (found in the Denoise slider of the HSL qualifier) is a more advanced algorithm that blurs based on both distance and brightness difference of nearby pixels [03:01]. [Image 13] This conserves details better and helps prevent halos, which are common beginner issues [03:17].

Color Management [03:44]

Proper color management is essential for Local Tone Mapping to work correctly. [Image 8]

Log footage [03:52]: For log footage, first add an Input Device Transform (IDT) node to convert the footage into a working color space like ACEScc/ct or DaVinci Wide Gamut Intermediate. The presenter prefers ACEScc.
Output Device Transform (ODT) [04:13]: Add an ODT node after all color corrections to convert the footage to the delivery color space (e.g., Rec.709).
Color Correction [04:22]: Perform initial color corrections (white balance, exposure) between the IDT and ODT nodes using global tools like HDR wheels [04:30]. This prepares the footage for local tone mapping adjustments.

ACES lite - Look Library [04:49]

The presenter offers a "LOOK LIBRARY" with pre-made Look Modification Transforms (LMTs) for DaVinci Resolve. These LMTs:

Provide professional grades often in one click [05:07]. [Image 7]
Offer nearly 20 synthetic and real film emulation looks [05:14].
Are parametric, allowing users to dive into the node structure and adjust sub-elements like halation, diffusion, and film grain [05:50].
Many include local tone mapping techniques similar to those taught in the video [05:43].

High light recovery [06:42]

Goal: Recover detail in bright sky areas without affecting mid-tones.

Initial correction [06:53]: Perform global color correction first. [Image 36]
Isolate highlights [08:30]: Use the HSL qualifier (black & white view) to select only the brightest areas (highlights) of the sky. [Image 37]
Refine mask [08:58]: Add a bit of ramp and denoise (bilateral blur) to soften the mask edges.
Apply adjustment [09:12]: Use global wheels or curves to bring down the exposure of the selected highlights. The Curves tool can adjust both exposure and contrast of the selected tonal area. [Image 38]
Avoid halos [10:17]: Aggressive adjustments can create halos around the recovered areas. Mitigation involves:
- Less aggressive adjustments.
- Using the Clean Black/White and Shrink/Grow tools in the HSL qualifier to refine the mask edges, reducing fuzziness and pushing the mask slightly inwards.
Benefit of Local Tone Mapping [08:08]: Performing local tone mapping before global exposure/white balance adjustments allows for more flexibility without altering the mask.

Fill light to shadows [10:29]

Goal: Add fill light to dark shadow areas in post-production, similar to using a reflector on set.

Initial correction [10:40]: Apply global color correction and a filmic look. [Image 29]
Isolate shadows [12:08]: Use the HSL qualifier to select the shadow areas (excluding highlights).
Refine mask [12:16]: Add a softer ramp and apply denoise (bilateral blur) to the mask. [Image 33]
Apply adjustment [12:35]: Use the Lift control or curves to lift the shadow areas. With curves, both exposure and contrast can be adjusted. [Image 34]
Benefit of Local Tone Mapping [11:51]: Local Tone Mapping allows precise brightening of shadows without affecting mid-tones, which would happen with global adjustments.

Negative fill in post [16:05]

Goal: Add negative fill (darken shadows) in post-production, simulating a black flag on set, which enhances contrast.

Initial setup [16:21]: Start with corrected studio footage and a filmic look. [Image 14]
Isolate shadows [17:56]: Select shadow areas using the HSL qualifier. [Image 20]
Refine mask [18:05]: Apply ramp and denoise (bilateral blur) for a smooth mask.
Apply adjustment [18:16]: Lower the exposure (e.g., using gamma or offset controls) of the selected shadow area. This deepens the shadows, creating more dramatic contrast without affecting mid-tones or highlights. [Image 19]

Mid-Tone Details [18:39]

Goal: Enhance three-dimensional depth and contrast in mid-tones without affecting highlights or shadows.

Initial setup [18:52]: Use pre-corrected footage with a filmic look.
Isolate mid-tones [20:30]: Select mid-tone areas using the HSL qualifier (excluding highlights and shadows). [Image 18]
Refine mask [20:36]: Apply ramp and full denoise (bilateral blur) for a smooth, localized mask.
Apply adjustment [21:05]: Add contrast to the mid-tones using global controls like the contrast slider or curves. This will make mid-tone areas more pronounced, creating a sense of depth, while highlights and shadows remain unaffected due to the localized mask.

Skin Tone Density [21:50]

Goal: Achieve cinematic or "filmic" density for skin tones, preventing a flat or overly sharp look.

Initial setup [22:02]: Start with corrected footage and apply a filmic look. Use highlight recovery if needed. [Image 24]
Isolate skin tones [23:19]: Use the HSL qualifier to select only the skin tones, then narrow and soften the selection with denoise. [Image 22]
Add density (Option 1) [22:42]: Use the custom color slice (density) controls to boost red, skin, and yellow values. This increases the density of the skin tones.
Add density (Option 2) [24:30]: Apply contrast (e.g., 1.2-1.25) and adjust the pivot to achieve desired density without oversaturating or flattening. [Image 27]
Remove harshness [24:50]: Use the Mid-Tone Details tool (found in the Blur section) to selectively soften or add texture to skin tones. By reducing local contrast, it can make skin look smoother without losing overall detail. A negative value smooths, a positive value adds texture.

Boosting light sources [25:41]

Goal: Make light sources appear brighter and more pronounced in the image. [Image 9]

Initial setup [25:49]: Use corrected footage with a filmic look. Note areas where highlights are blown out.
Isolate light sources [27:44]: Use the HSL qualifier to select only the brightest pixels (the actual light sources). Use a very narrow and precise selection.
Refine mask [27:56]: Apply minimal denoise (bilateral blur) to slightly soften the mask edges.
Apply adjustment [28:01]: Use the HDR wheels or gain/offset controls to boost the exposure of the selected light sources. Because the mask is highly localized, only the light sources will be affected, making them appear to "glow" more intensely without spilling into surrounding areas.

Fixing common issues [28:26]

Common issues and their fixes when using Local Tone Mapping:

Halos [28:31]: Halos appear as a "fuzziness" or an unnatural glow around aggressive highlight or shadow adjustments.
- Mitigation 1: Less aggressive adjustments [29:00]: Reduce the intensity of your tonal adjustments.
- Mitigation 2: Clean White/Black and Shrink/Grow [31:24]: Use the "Clean White" or "Clean Black" sliders in the HSL qualifier to erode fuzzy edges. The "Shrink/Grow" morph operation can push the mask slightly inwards to cover up halos [32:17]. [Image 28]
Exaggerated texture/sharpness [33:10]: Adding too much contrast, especially mid-tone contrast, can over-sharpen skin tones or textures.
- Mitigation: Mid-Tone Details [34:00]: Use the Mid-Tone Details tool to selectively reduce local contrast. A negative value smooths the skin/texture without making it blurry or losing overall detail.
Global tool limitations [32:37]: Global tools (e.g., contrast) affect the entire image, leading to unintended side effects like crushed shadows or blown-out highlights when targeting specific tonal areas.
- Solution: Local Tone Mapping [32:48]: Local Tone Mapping allows adjustments to specific tonal ranges without impacting others, preserving a more natural and realistic look.