Deband

Banding is especially visible in skies, plain walls, haze, vignettes, glows and dark gradients. Resolve 21 describes the common low-bit-depth case: too few representable values turn a smooth gradation into visible stripes.

Deband does not reconstruct missing original shades and it is not a general blur or noise-reduction filter. Blackmagic describes it as isolating the edges of color banding and minimizing them by dithering pixels from either side of the edge.

That distinction creates the main production risk. If you treat Deband as a global smoothing filter, genuine edges can also be dithered and softened. The manual therefore recommends isolating the problem region; in Fusion an effect-mask branch serves the same practical purpose.

Edge Threshold defines how well-defined an edge must be to be affected. The direction matters: lowering the value excludes fainter edges, while raising it includes them. A higher threshold can therefore bring more real contours into the operation rather than simply 'protecting edges more strongly.'

Radius is not a geometric blur radius or a search-neighborhood size. Resolve 21 defines it as lowering or raising the intensity of dithering in the areas that will be affected. The older article's spatial-radius explanation was incorrect.

Post Refine is also not a generic final quality pass. Lowering it narrows the areas affected by dithering and raising it widens those areas. Radius and Post Refine therefore describe two different axes: intervention strength versus affected-area width.

Display Edge is a black-and-white high-contrast diagnostic preview of the edges detected for dithering. Use it to tune detection and collateral targets, then turn it off before judging the final image.

A reliable tuning order is diagnostic first, strength second: Display Edge + Edge Threshold, then Radius, then Post Refine. If the problem is local, mask it before making threshold/radius aggressive; that reduces the chance of damaging skin texture, type, fine lines or grain elsewhere.

Deband and Dither are related but not interchangeable. Deband first detects band edges and acts selectively around them, whereas a general Dither stage can add low-level variation more broadly around quantization. Very subtle downstream grain can be useful after repair, but it should not hide bad Deband settings.

Place Deband after the stage that actually creates or reveals the banding. For baked-in source banding that may be early in the flow; if a heavy grade creates the visible steps, it is more logical to repair after that grade. There is no universal 'always first' placement.

Judge the result at 100%/target resolution and in motion. Viewer Fit can hide fine banding, while excessive dithering or texture loss may be easier to notice during playback than in one still frame.

Resolve 21 lists Deband under Resolve FX Revival and marks it Studio Version Only. Resolve FX are available on the Fusion page in DaVinci Resolve, while Blackmagic separately notes that Resolve FX are not available in standalone Fusion Studio.

The captured Fusion Inspector confirms the four core controls and baseline values: Edge Threshold 0.025, Radius 3, Post Refine 0.05 and Display Edge off. Treat those as captured starting points, not production presets; the correct values depend on the shot.

The first diagnostic mistake with Deband is treating every smooth-looking region as a banding problem. The filter is intended for visible quantization steps or bands, not general smoothing.

Banding may be baked into the source, amplified by compression, or created by a downstream grade. Place Deband after the stage where the defect actually becomes visible rather than following a universal always-first recipe.

An Effect Mask is especially valuable when a sky or wall sits next to hair, branches, architecture, text or grain. Spatial isolation lets Edge Threshold and Radius stay useful without unnecessary global collateral damage.

Tune Edge Threshold with Display Edge while keeping Radius and Post Refine stable. This separates detector errors from dither-strength errors and preserves clear cause and effect.

Raising Edge Threshold includes additional or fainter edges according to the Resolve 21 semantics. The intuition that a higher threshold protects detail more strongly is wrong here.

Radius controls dither intensity rather than geometric search width. If the affected zone spreads too far, inspect Post Refine and the spatial mask instead of only changing Radius.

Post Refine controls affected-area width around selected band edges. Too little can leave the step visible; too much can reach neighboring texture.

Display Edge changes the representation of the normal image Output and does not create a separate blue mask stream.

With Display Edge enabled, compare the target band edges against genuine object edges nearby. If real contours dominate the map, threshold or masking is already too aggressive.

On 8-bit or heavily compressed footage, Deband may reduce visible stepping but cannot recover tones that were never recorded. It hides discreteness through dithering rather than reconstructing original high-bit-depth information.

A later 8-bit quantization or aggressive encode can reintroduce banding after a successful repair. Evaluate Deband together with the downstream precision and delivery path.

Very subtle downstream Grain or Dither can make a repaired smooth region feel less sterile, but it should not be used to hide a bad Edge Threshold or Radius decision.

Motion-graphics and synthetic gradients are useful diagnostic sources because the expected background is mathematically smooth. They make Radius/Post Refine behavior easier to study.

On camera footage, native texture can partially hide banding. Strong denoise or grading may reveal it later, so Deband often belongs after the operation that exposed the steps.

If banding is visible only at extreme zoom and disappears at the target display size, aggressive Deband may do more harm than good. Judge the defect under delivery conditions.

If banding appears only in one channel or after a specific color transform, inspect the upstream signal path first. Deband should not replace fixing an incorrect bit-depth or color-management stage.

Mask boundaries also require QC: an overly hard Effect Mask can create a visible seam between debanded and untouched regions. Feather belongs in the mask branch, not in Radius/Post Refine.

With an animated mask, Deband remains a spatial image effect, but the changing allowed region can create temporal variation. Review the full animation in playback.

Final QC has three layers: the detector map through Display Edge, RGB A/B at 100 percent, and playback or encoded-preview review. Any one layer alone is insufficient.

The captured 0.025 / 3 / 0.05 values are useful UI references, not recommended presets. Source scale, bit depth and grading change the correct settings.

Resolve FX deployment matters when handing off the project: Deband is documented as Studio-only in Resolve 21 and is not a normal standalone Fusion Studio node.

For automation, confirm internal parameter IDs from a .setting or .comp exported by the target Resolve build. UI labels and static documentation do not guarantee serialization.