RESOLVE FX · RESTORATION LOGIC
Automatic Dirt
Removal.
Detect first.
Repair second.
Temporal dirt removal is not a stronger blur. Understand motion estimation, neighboring frames and the repair mask — then protect grain, motion and edges before increasing repair strength.
Motion + Frames
Mask + Thresholds
Strength + Blend
In the lab, switch to “Grain”, enable Show Repair Mask and raise Dirt Size Thr. Then open “Motion” and watch risky candidates react to Motion Thr. and Edge Ignore.
Independent deterministic teaching proxy. It illustrates the causal order — motion context → size/motion/edge classification → repair amount → final blend. The numeric scales, synthetic marks, detector score and repaired pixels are illustrative and do not reproduce Blackmagic optical flow, thresholds or OFX rendering.
Actual Resolve screenshots + an explicitly labeled teaching proxy.
8 controls · 4 exercises01TEMPORAL RESTORATION
The effect has two jobs: classify, then repair.
A transient speck and a moving eyelash can both change between frames. The useful result comes from separating those behaviors before replacing pixels.
A transient defect is not scene detail
Automatic Dirt Removal is useful because it reasons across time. Dust or a tape hit often appears for one or two frames and disappears, while real scene detail persists and merely changes position. Temporal analysis plus motion estimation tries to separate those two behaviors.
Tune detection before repair
Repair Strength cannot fix a wrong classification. If Show Repair Mask already includes hair, skin texture, film grain or an architectural edge, increasing Repair Strength only damages useful detail more aggressively. Clean the mask with size, motion and edge controls first, then dose the repair.
Temporal window is context, not blur radius
Neighbor Frames controls how many adjacent frames participate in the comparison. It is not a spatial radius or a generic effect-strength control. A wider temporal window can help with short-lived defects, but fast motion and clip boundaries must be checked frame by frame.
A long static scratch or lens dirt may remain in the same location for the whole shot. To a temporal detector, that can look like a persistent part of the image. Use Automatic Dirt Removal as an automatic first pass for transient defects and move persistent damage to targeted repair tools.
02THE ACTUAL PANEL
Tune evidence before intensity.
Six native captures document the visible controls and both dropdown menus. The captured values are UI evidence, not a recommended preset or claimed parameter ranges.
TEMPORAL ANALYSIS
Match motion before judging dirt
- Motion Est. Type
Chooses the motion-estimation mode: None, Faster, Normal or Better. This is a temporal-matching quality/cost control, not a creative preset. Normal is a sensible baseline; Better is worth testing on complex motion; Faster favors interactivity; None is useful as a diagnostic A/B.
CheckInspect hair, fine text, motion blur and occlusions. If Better does not improve the mask, the extra processing cost buys nothing.
- Neighbor Frames
The captured Resolve 21 menu exposes 1, 2, 3 and 4. A larger value gives the detector more temporal samples, but also increases processing cost and the chance of poor matching in difficult motion. The captured value of 2 is a reference state, not a universal recommendation.
CheckCompare the same defect with 1–4 frames and always inspect the head and tail of the clip where less temporal context may be available.
DETECTION → REPAIR
Separate detector decisions from repair amount
- Repair Strength
Controls how aggressively regions already classified as dirt or artifacts are repaired. The panel shows 0.900 as a captured UI state. If the mask is wrong, changing Strength is not a substitute for tuning detection.
CheckRaise it only after Show Repair Mask is clean. Aim for the minimum strength that makes the defect stop distracting rather than maximum removal.
- Dirt Size Thr.
Filters candidates by scale. A higher threshold helps prevent fine texture and film grain from being treated as dirt, but can let small specks pass. This makes the control especially important on film scans and noisy sources.
CheckIf the repair mask becomes a fine spray across the frame, raise Dirt Size Thr. in small steps first.
- Show Repair Mask
A diagnostic switch that shows which regions the detector intends to repair. This is the primary tuning view because it separates “what does the effect classify as damage?” from “how visible is the final repair?”
CheckStep through multiple frames. A good mask consistently catches transient dirt without flashing across real moving details.
FINE CONTROLS
Protect motion and real edges
- Motion Thr.
Changes the detector tradeoff between remaining dirt and the risk of classifying real temporal change as damage. A more permissive setting can catch more dirt, but increases the chance of swimming patches, lost texture and damage to moving subjects.
CheckIf the mask follows real motion, reduce Motion Thr. aggressiveness and compare Normal versus Better motion estimation instead of hiding the error with Blend.
- Edge Ignore
Helps exclude strong real boundaries from automatic repair. It is especially useful around hair, eyelashes, text, wires and architectural lines where a transient detector can confuse thin high-contrast detail with damage.
CheckDo not protect edges more than necessary: real dirt near a boundary can also disappear from the repair mask.
FINAL MIX
Dose the finished repair separately
- Global Blend · Blend
Mixes the repaired output with the source after detection and repair have already been computed. Blend is useful for final easing, but it does not fix false positives in Show Repair Mask and does not replace the thresholds.
CheckFirst obtain a clean mask and stable playback at Blend 1.0, then reduce Blend only if the finished restoration feels too sterile.
The panel shows Normal, Neighbor Frames 2, Repair Strength 0.900, Dirt Size Thr. 0.100, Motion Thr. 100.0, Edge Ignore 0.000 and Blend 1.000. Treat those as a captured state only; tune from the defect, motion and texture of the actual shot.
03A DETECTOR-FIRST PATH
Do not chase every defect with one threshold.
The efficient restoration path is classification → temporal matching → repair-mask QC → minimum repair → playback QC → targeted cleanup for the leftovers.
Establish temporal matching
Start with Normal and a modest Neighbor Frames value. Compare the same difficult segment before spending time on thresholds. Better is useful only when it actually improves matching.
Teaching workflow, not a literal Resolve node graph. The key decision is detector-first: diagnose the repair mask before increasing repair amount.
Related repair tools: Dust Buster ↗ · Patch Replacer ↗ · Dead Pixel Fixer ↗
04BUILD IT IN RESOLVE
Four exercises that expose different failure modes.
Use your own footage. These are diagnostic exercises, not one-click recipes, and the exact settings depend on source texture, resolution, motion and defect duration.
Transient dust on a film scan
Remove many short-lived specks while preserving grain.
PrepareChoose a segment with visible dust and a separate frame where fine texture or grain is easy to judge.
- 01
Start with Motion Est. Type = Normal and Neighbor Frames = 2 as a neutral comparison point, not a finished preset.
- 02
Enable Show Repair Mask and raise Dirt Size Thr. until grain mostly leaves the mask while real specks remain.
- 03
Check several frames and only then set Repair Strength to the minimum effective level.
- 04
Disable the mask and compare bypass during playback and at 100% Viewer scale.
Dust stops distracting while grain and fine texture remain continuous between repaired and neighboring regions.
Protect film grain
Separate real fine texture from dirt candidates.
PrepareFind a flat region with clearly visible grain and several real dust particles of different sizes.
- 01
Show the Repair Mask and keep Repair Strength moderate while tuning.
- 02
Raise Dirt Size Thr. in small steps until the fine grain spray no longer dominates the mask.
- 03
Confirm that larger real specks are still detected; if not, step the threshold back.
- 04
After the final repair, compare noise and grain continuity in neighboring frames.
The mask does not blanket the grain, and repaired patches do not look like sterile islands.
Complex motion and hair
Remove transient dirt without losing moving fine detail.
PrepareUse a segment with fast head or hair motion, motion blur or occluding objects.
- 01
First compare Normal and Better with all other settings unchanged.
- 02
In Show Repair Mask, look for real detail that flashes as a false defect.
- 03
Reduce Motion Thr. aggressiveness; on hard contours, increase Edge Ignore carefully.
- 04
Check both frame-step and playback: one clean still does not prove temporal stability.
Transient dirt disappears without swimming or soft patches on hair, text and moving edges.
Automatic first pass plus manual cleanup
Avoid forcing one temporal effect to solve every damage type.
PrepareMark transient specks separately from persistent scratches or lens dirt in the same restoration shot.
- 01
Tune Automatic Dirt Removal only for transient defects; do not push thresholds merely to chase persistent damage.
- 02
Identify the areas that remain after the automatic pass.
- 03
Move isolated persistent defects to Dust Buster, Patch Replacer or a targeted paint/clone workflow.
- 04
Finally compare the whole shot with bypass: automation must not create more artifacts than it removes.
Automatic Dirt Removal handles broad first-pass cleanup while difficult persistent defects are repaired selectively.
05CHOOSE THE RIGHT REPAIR
Automatic Dirt Removal is a first pass, not a universal eraser.
| FX | What it is best at | Use it when |
|---|---|---|
| Automatic Dirt Removal | Temporal detector plus automatic repair for transient dirt. | Broad first pass on short-lived dust and dirt. |
| Dust Buster ↗ | More targeted restoration for individual defects. | Difficult spots the automatic detector cannot repair cleanly. |
| Patch Replacer ↗ | Explicit source/target patch replacement. | Persistent local damage with a usable source area. |
| Dead Pixel Fixer ↗ | Targeted repair of stable defective pixels. | Persistent dead or stuck pixels rather than time-varying dirt. |
| Deflicker ↗ | Temporal stabilization of brightness or exposure flicker. | Temporal luminance fluctuations rather than local specks or scratches. |
06DIAGNOSE THE FAILURE
A bad mask, a bad match and an over-strong repair are different problems.
Classify the symptom before changing sliders. Global Blend cannot repair a false detector decision, and a larger temporal window cannot turn persistent lens dirt into a transient defect.
01Repair Mask lights up across the grain+
Likely cause: The detector is treating fine texture as dirt: Dirt Size Thr. is too permissive for this source.
Fix: Raise Dirt Size Thr. in small steps and compare the mask over several frames. Repair Strength is secondary here.
02Soft or swimming patches appear on a moving face or hair+
Likely cause: Temporal matching is failing or Motion Thr. is allowing the detector to classify real motion as damage.
Fix: Compare Better with Normal, reduce Motion Thr. aggressiveness and inspect Show Repair Mask frame by frame.
03Dust near text or architecture is repaired together with the edge+
Likely cause: The detector is not separating the transient spot from the real hard boundary.
Fix: Raise Edge Ignore enough to remove the boundary from the mask while keeping nearby dirt as a candidate.
04A static scratch survives aggressive settings+
Likely cause: The damage is persistent and does not provide the transient temporal evidence the detector expects.
Fix: Stop pushing the detector. Move to Dust Buster, Patch Replacer or manual paint/clone repair.
05A still looks clean but playback flickers+
Likely cause: Detection or repair is changing frame to frame; temporal stability has not been established.
Fix: Revisit Neighbor Frames, motion estimation and the mask on the difficult segment; judge the sequence rather than a hero frame.
06The cleaned frame feels unnaturally sterile+
Likely cause: Repair Strength or Global Blend is making the intervention too strong even though detection is correct.
Fix: First reduce Repair Strength to the necessary amount; if the repair structure is sound, ease the final result with Global Blend.
07BEFORE DELIVERY
Approve the sequence, not the cleanest still.
Temporal restoration can look perfect on one frame and fail in motion. Final QC needs repair-mask logic, texture continuity, playback and clip-boundary checks.
08FAQ
Practical Automatic Dirt Removal questions.
What is Automatic Dirt Removal best suited for?
For short-lived dust, dirt, hairs, tape hits and similar defects that appear for one or a few frames and then disappear. That temporal instability gives the detector useful evidence.
Which Motion Est. Type should I choose?
Normal is a strong baseline. Faster favors speed, Better is worth testing when complex motion genuinely benefits from more careful matching, and None is a diagnostic mode without motion compensation.
Why does the effect start removing film grain?
The detector is classifying fine texture as dirt. First raise Dirt Size Thr. and inspect Show Repair Mask; Repair Strength should be tuned only after classification is correct.
Will Automatic Dirt Removal remove a long static scratch?
Not reliably, and that is often outside its strongest use case. A persistent scratch that remains in the same location for many frames is hard to distinguish from permanent image detail and is better handled by targeted repair.
Should I always use Neighbor Frames = 4?
No. A wider temporal window gives more context but costs more processing and may not improve matching on fast motion. Compare values on the same difficult segment.
Can Global Blend fix false positives?
It only reduces the consequence; the detector remains wrong. The correct order is to clean Show Repair Mask with thresholds and estimation, tune Repair Strength, and only then use Blend for final dosing.
Sources and boundaries
The page separates UI evidence from the teaching model. Control names and dropdown choices come from the six native Resolve captures in the project archive; the interactive detector is an independent deterministic proxy. It does not claim Blackmagic’s exact optical-flow math, threshold mapping, replacement pixels or render performance.
Check the effect in your installed Resolve build for edition availability and interface differences. The exercises in this site update were not certified by a live Resolve render; they are explicit training procedures built around the captured controls and conservative restoration practice.