RESOLVE FX · TONAL-STEP RESTORATION
Deband.
Find the step.
Dither only there.
Deband is not a blur preset for ugly gradients. It is a detector-first restoration pass: isolate the damaged gradient, expose the band map with Display Edge, decide which tonal steps are eligible, then add only enough dithering to make the transition stop reading as a stripe.
Qualifier / Window
Threshold / Edge
Radius / Refine
In the lab, enable Display Edge and move Edge Threshold first. Notice how the selected band map changes before Radius does anything useful. Then compare a smooth sky with Graphics, where real hard edges must stay protected.
Read the causal chain+
Detection: 34% · 39% of teaching frame selected
Repair: Radius 34% · Post Refine 22%
Mix: Blend 1.00
Independent teaching proxy, not Resolve rendering. The source is deliberately quantized and the detector/dithering are simplified to demonstrate the order Edge Threshold → Radius → Post Refine → Blend. Percent scales, sampling, mask coverage and pixel synthesis do not reproduce Blackmagic internals or parameter mapping.
Three native Resolve 21 captures + an explicitly labeled synthetic banding proxy
3 captures · 5 controls · 4 exercises01WHAT DEBAND ACTUALLY REPAIRS
The problem is a visible quantization step.
A shallow gradient can break into stripes when there are not enough values to describe it smoothly. Deband does not invent the missing original bit depth; it makes the step less visible while trying to leave meaningful image edges alone.
Banding is tonal stepping, not ordinary noise.
In shallow low-bit-depth gradients or aggressively compressed media, a smooth transition can collapse into visible tonal bands. Deband finds the boundaries of those steps and softens the transition by dithering neighboring values. It does not reconstruct missing source bit depth and should not be treated as a global blur.
The detector matters more than raw strength.
Edge Threshold decides which band boundaries are eligible for processing. The manual states that lowering it excludes fainter edges while raising it includes them. Build a trustworthy detector mask with Display Edge first, then increase Radius.
Local isolation protects real edges.
Blackmagic explicitly recommends applying Deband to an isolated region with a secondary qualifier or window. Otherwise dithering can reach normal contours, text, skin and texture that are not banding at all.
If the detector captures the wrong edges or Radius is too aggressive, Global Blend only hides the cause. Fix selection and intervention width first; use Blend at the end once the repair itself is logically correct.
02THE ACTUAL PANEL
Five controls. Three different jobs.
Three native Resolve screenshots document the complete visible Deband control story: detection with Edge Threshold and Display Edge, repair with Radius and Post Refine, then the standard Global Blend.
01 · DETECTION
First decide which edges count as banding.
- Edge Threshold
Controls how well-defined an edge must be to be affected by Deband. According to the manual, lowering excludes fainter edges while raising includes them. In practice this is detector sensitivity, not blur strength.
CheckTurn on Display Edge. Raise Threshold only until band boundaries are confidently visible in the diagnostic preview while meaningful texture and object edges remain protected.
- Display Edge
Shows a black-and-white high-contrast preview of edges detected for dithering. It is a diagnostic output, not the final image.
CheckTune Threshold here, then turn Display Edge off before evaluating the final result.
02 · DITHERING
After detection, set the strength and width of the intervention.
- Radius
Raises or lowers the intensity of dithering in areas already selected by the detector. It changes the repair itself, not which edges are classified as banding.
CheckUse the minimum setting that stops the tonal step from calling attention to itself. Excessive Radius starts reducing local contrast and perceived detail.
- Post Refine
Narrows when lowered or widens when raised the area affected by dithering after detection. It controls the footprint around the detected edges.
CheckIf the correct band edges are detected but the repair spills into surrounding texture, reduce Post Refine before reaching for Blend.
03 · FINAL MIX
Meter the finished repair, not the detector.
- Global Blend · Blend
The standard Resolve control that mixes the effect result with the incoming image. It is useful for final fine dosage after Deband is already tuned correctly.
CheckIf Blend has to be reduced heavily, return to Threshold, Radius, Post Refine or node isolation; the real cause is usually upstream.
Treat 0.025, 3, 0.050 and 1.000 in the screenshots as captured interface state, not parameter limits or recommended values. The reliable order is qualitative: isolate → Display Edge → Threshold → Radius → Post Refine → Blend.
03READ DISPLAY EDGE BEFORE YOU REPAIR
A clean band map is worth more than a strong Radius.
Display Edge separates three very different states: missed bands, useful detection and a detector that has started swallowing real image structure. Diagnose that state before changing the repair.
Bands are missing
The diagnostic view does not show the faint tonal boundaries that are obvious in the final image. Radius cannot repair edges the detector never selected.
Increase Edge Threshold gradually while watching the map.
Bands selected, contours protected
The tonal steps appear in the mask but text, faces, architecture and other meaningful boundaries are mostly dark. This is the state in which Radius becomes a meaningful control.
Return to Final Result and add the minimum useful dithering.
Real structure lights up
Hair, typography, object outlines or texture are bright in Display Edge. Full-frame use or an overly permissive threshold is now exposing real detail to dithering.
Lower Threshold and/or isolate the problem with a qualifier/window.
Manual reference: Resolve FX Revival · Deband Parameters ↗
04DETECTOR-FIRST WORKFLOW
Isolate first. Blend last.
The efficient path is classify → isolate → make detection visible → set minimal dithering → tighten the footprint → judge motion and the real delivery encode.
Confirm that the defect is tonal stepping
Look for stable visible stripes inside an otherwise smooth gradient. Random noise, macroblocking, flicker and clipping are different failures and need different tools.
Teaching workflow, not a literal Resolve node graph. Its purpose is to preserve causality: isolate first, validate the detector, then tune dithering and only after that use Global Blend.
Related finishing context: Qualifier / Windows / Tracker ↗ · Film Grain ↗
05BUILD IT IN RESOLVE
Four gradients. Four different failure boundaries.
Use your own footage or graphics. These are diagnostic exercises, not value recipes: exact Threshold, Radius and Post Refine depend on the source, display transform and delivery codec.
8-bit sky with visible bands
Soften tonal steps without smearing silhouettes or cloud texture.
PrepareCreate a dedicated Color node and isolate the sky with a qualifier/window.
- 01
Enable Display Edge and tune Edge Threshold so the preview shows sky bands without selecting building or tree contours.
- 02
Disable Display Edge and raise Radius only until the distracting stepping is no longer obvious.
- 03
Use Post Refine if dithering reaches too broadly around detected steps.
- 04
Check playback and a short export; reserve Global Blend for the final dose.
The gradient reads smoother while real edges and cloud detail stay intact.
Smooth wall or studio backdrop
Remove bands from a smooth surface while protecting face, hair and clothing.
PrepareConstrain the effect to the wall or backdrop rather than the whole frame.
- 01
Verify the isolation matte first.
- 02
Use Display Edge to separate tonal-step edges from wall texture and shadows.
- 03
Tune Radius and Post Refine at a useful 100% viewing scale.
- 04
Watch mask boundaries in motion, especially around hair and shoulders.
The background becomes smoother without obvious softening of the subject.
Generated gradient or motion graphic
Hide posterization after codec/export without turning graphics into blur.
PrepareUse a test export where banding is actually visible, not only the pristine timeline source.
- 01
Compare source and delivery codec to confirm the artifact you are repairing.
- 02
Display Edge should reveal gradient steps rather than typography and shape edges.
- 03
Choose the minimum useful Radius and a conservative Post Refine.
- 04
Repeat the check after the final encode because the codec can alter banding again.
The gradient looks less stepped while typography remains crisp.
Dark haze / low-light gradient
Soften low-level bands without erasing faint texture or the noise floor.
PrepareWork through the final display transform and inspect the darkest regions on the real monitor.
- 01
Isolate only the problematic haze/sky.
- 02
Keep the detector conservative because faint real detail is easy to confuse with band boundaries.
- 03
Increase Radius in small steps and compare bypass constantly.
- 04
After Deband, verify that the natural grain/noise character has not changed undesirably.
The dark gradient reads calmer without turning the shot into a waxy surface.
06CHOOSE THE FAILURE, THEN THE TOOL
Not every ugly gradient is a Deband problem.
Stable tonal steps, temporal flicker, random noise and transient dirt can look equally “digital” at a glance but need different repair models.
| FX | What it actually targets | Choose it when |
|---|---|---|
| Deband | Edge-aware dithering for visible tonal steps in shallow gradients. | When the problem is specifically banding/posterization in a smooth transition. |
| Deflicker ↗ | Temporal repair for rapidly unstable lightness changes. | When the defect changes over time: exposure, fluorescent or archival flicker. |
| Noise Reduction ↗ | Spatial/temporal noise reduction rather than tonal-step repair. | When the problem is random luma/chroma noise rather than stable bands. |
| Film Grain ↗ | Adds controlled texture that can sometimes help visually break up residual posterization. | After a correct Deband pass when delivery still looks overly digitally smooth. |
| Automatic Dirt Removal ↗ | Temporal detection of transient dirt/specks, not gradient repair. | When the artifact is a transient speck rather than a gradient band. |
07DIAGNOSE BEFORE BLENDING IT AWAY
Missed bands, softness and re-banding have different causes.
Read the symptom before moving Global Blend. Detector coverage, repair intensity, footprint and delivery quantization sit at different points in the causal chain.
01Banding barely changes+
Likely cause: The detector is not including the faint band edges, or Radius is too low after detection is correct.
Fix: Enable Display Edge. If the bands are absent from the preview, gradually raise Edge Threshold. If they are already visible, return to final view and carefully increase Radius.
02Skin, hair or text became softer+
Likely cause: The effect is covering the whole frame, the detector captured real edges, or Post Refine/Radius is too aggressive.
Fix: First isolate the node with a qualifier/window, then use Display Edge to reduce unwanted contour capture before lowering Radius/Post Refine.
03A broad soft region appears around the bands+
Likely cause: Post Refine widened the footprint or Radius became too strong.
Fix: Narrow Post Refine and reassess Radius. Do not solve it only with Global Blend.
04Display Edge lights up most of the frame+
Likely cause: Edge Threshold is too permissive for the scene or the isolation is too broad.
Fix: Lower Threshold to a stable detector state and isolate the problematic region with a window/qualifier.
05Looks good on the timeline but bands return after encode+
Likely cause: The delivery codec/bit depth quantizes the gradient again after node processing.
Fix: Check a short final encode. Debanding the source cannot guarantee that an aggressive codec will not create new steps; revisit export settings and, if appropriate, add very subtle texture.
06A very low Global Blend is the only way to make the shot acceptable+
Likely cause: The repair is too broad or too strong upstream.
Fix: Return Blend toward full effect and correct Threshold, Radius, Post Refine and isolation. Then use Blend again only as the final dose.
08BEFORE DELIVERY
Approve Deband in the encoded picture, not only the timeline.
Banding is unusually sensitive to bit depth, transforms, display conditions and the delivery codec. The final check must include the path the viewer will actually see.
09FAQ
Practical Deband questions.
What exactly does Deband do?
It isolates color-banding edges and reduces their visibility by dithering pixels from both sides of the tonal step. It is a specialized restoration effect, not a conventional blur.
Why should Display Edge be used first?
Because it reveals what the detector intends to process. That separates a detection mistake from excessive Radius and prevents blind tuning.
Should Deband be applied to the whole frame?
Usually not. Blackmagic recommends isolating the problematic region with a secondary qualifier or window, otherwise ordinary edges can also be dithered and softened.
Does Deband restore original 10-bit/12-bit information?
No. It makes visible steps less obvious but cannot reconstruct values that were not present in the source. It is a perceptual repair, not restoration of lost bit depth.
How is Radius different from Post Refine?
Radius changes dithering intensity inside selected areas; Post Refine narrows or widens the affected areas around detected edges. One governs repair strength, the other its footprint.
Should grain be added after Deband?
Sometimes very subtle texture helps a delivery survive re-quantization, but that is a separate technical/creative choice. Deband should first be correct on its own, and any grain should be evaluated in the final encode.
Sources and boundaries
The page separates captured UI evidence from the interactive teaching model. Control names and documented behavior are anchored by three native Resolve captures plus the Resolve 21 Revival manual. The hero lab is an independent synthetic proxy; it does not reproduce Blackmagic edge detection, dithering synthesis, color-management behavior or parameter scales.
Check the effect in your installed Resolve build for edition availability and interface differences. The exercises are conservative workflows based on documented controls and captured UI; they are not claimed as live-render certification for every codec, display transform or source bit depth.