RESOLVE 21 · TEMPORAL FRAME ACCUMULATION
Smear.
Choose the time window.
Then choose which pixels may enter it.
Resolve FX Smear is deliberately compact: it blends frames on both sides of the current image, filters contribution by luminance and saturation, then exposes one final Global Blend. The small panel is deceptive—the real craft is separating temporal duration from pixel selection so fast motion, highlights, saturated color, and edit boundaries do not all accumulate the same way.
Frames Either Side
Luma + Chroma Threshold
Global Blend · playback QC
In the lab, make the temporal window too long first, then use the Luma and Chroma gates separately. The useful lesson is that thresholds change what contributes, while Blend changes how much of the already-built result you see.
Teaching proxy, not Resolve rendering. The canvas intentionally simplifies symmetric temporal sampling and the Luma/Chroma contribution gates so their dependency is visible. It does not reproduce Blackmagic OFX internals, exact threshold math, color management, sampling, or renderer precision.
Four native Resolve interface views + an explicitly synthetic symmetric-window teaching proxy
4 native views · 4 controls · 4 exercises01WHAT SMEAR ACTUALLY ACCUMULATES
A temporal window first. Pixel contribution second.
There is no motion-vector panel here. Smear takes neighboring temporal samples, lets Luma Threshold and Chroma Threshold decide what contributes, and only then mixes the result back with the source.
Smear is symmetric temporal accumulation
The effect samples frames before and after the current frame and blends them around the present position. Frames Either Side therefore controls a temporal window rather than a spatial blur radius. Uniform motion becomes a long trace; direction changes, occlusion, or a hard edit can make neighboring frames conflict and create doubled contours.
Thresholds decide what is allowed to smear
Luma Threshold and Chroma Threshold are independent contribution gates. The first widens the admitted brightness range, the second the saturation range. At 100/100 the effect receives the broadest material; lowering either threshold excludes part of the bright or saturated content. That is why thresholds should be tuned against problematic subjects rather than treated as generic strength controls.
Smear does not solve a motion vector like Motion Blur
There is no Motion Est. Type, Motion Range, or Blur Direction here. The trace comes from direct blending of neighboring temporal samples and their pixel contribution. That makes Smear useful for deliberately temporal imagery, but less suitable when you need physically plausible directional shutter-like blur.
A reliable setup order is to choose window length with Frames Either Side, restrict contribution with Luma/Chroma Threshold, and only then touch Blend. If the subject already doubles or neon turns into a colored mass, lowering Blend may hide the symptom, but the correct fix is upstream.
02FOUR CONTROLS · THREE DECISIONS
Read the native panel as time → selection → final mix.
The screenshots below are the real project assets. Values such as 5, 100.0, and 1.000 are captured interface states, not presets; the surrounding copy explains the job of each control instead of recommending those numbers.
TEMPORAL WINDOW
Set accumulation length first
- Frames Either Side
Sets how many frames before and after the current frame participate in Smear. With a value of 5, the window reaches five previous and five following frames around the current frame. Raising the value lengthens the temporal trace while increasing the chance of conflicts at occlusions, acceleration, direction changes, or near an edit point.
CheckTune it during playback rather than on one still. If the trace is already longer than needed or the subject splits into several readable positions, shorten the window before touching thresholds.
PIXEL CONTRIBUTION
Restrict which pixels may enter the accumulation
- Luma Threshold
Determines the brightness range of pixels admitted to the smear. A low value restricts contribution to darker pixels; increasing it allows progressively brighter regions to participate. This is not an amount or opacity control: changing the threshold changes the content of the temporal blend rather than simply scaling a finished effect.
CheckWatch windows, lamps, specular highlights, and bright text. If those regions create an overly long or dominant trail, lower Luma Threshold instead of breaking the temporal window for the rest of the frame.
- Chroma Threshold
Filters contribution by saturation. A low value keeps the smear mostly to less-saturated regions, while a high value admits increasingly saturated colors. The difference can be subtle on neutral footage, but RGB lighting, neon, clothing, and graphics quickly reveal how strongly colored trails depend on this control.
CheckIf the luminance trace looks good but saturated color drags into a heavy stripe, lower Chroma Threshold first. This can preserve tonal motion history without desaturating the source or reducing the whole Blend.
FINAL MIX
Dose an already-correct result
- Global Blend · Blend
Mixes the calculated Smear with the original image. In the capture, Blend = 1.000 shows the full effect; lowering it restores more source sharpness and temporal separation. This is the overall mix after the window and thresholds are evaluated, not an alternate way to limit duration or pixel selection.
CheckSet Blend last and check playback again. If you must pull it down dramatically to make the image acceptable, return to Frames Either Side and the thresholds: the upstream setup is probably still too aggressive.
A practical rule: if Smear becomes muddy, diagnose whether the problem is temporal length, brightness contribution, or saturation contribution before lowering Blend. The three upstream causes need different controls.
03A REPEATABLE SMEAR WORKFLOW
Source → window → luma gate → chroma gate → mix → QC.
This order prevents Global Blend from becoming a blanket fix for a window that is too long or a contribution gate that is too open.
Choose the motion section
Loop the fastest movement, direction change, occlusion, or edit boundary. Smear is temporal, so start from a section that can reveal temporal failure.
This is an editorial decision path, not Blackmagic’s published internal processing graph. It separates temporal duration, luminance contribution, chroma contribution, final mixing, and motion QC so Blend never substitutes for correct upstream selection.
Related reference: Motion Blur ↗ · Motion Trails ↗ · Stop Motion ↗
04FOUR TEMPORAL DECISIONS
Motion, lights, graphics, and edit boundaries fail differently.
Treat these as decision recipes rather than numerical presets. The correct frame window depends on source cadence and motion; thresholds depend on the brightness and saturation structure of the actual shot.
Soft temporal motion
Add a short trace to movement without turning the subject into a stack of separate ghosts.
- 01
Start with a small Frames Either Side value and loop the fastest section of motion.
- 02
Keep thresholds high only if the whole frame tolerates accumulation; otherwise restrict problematic highlights or saturated colors.
- 03
If direction changes create doubled contours, shorten the temporal window before touching Blend.
- 04
Use Blend last for fine dosage after the trace itself is clean.
Light trails and stage footage
Make light trajectories expressive without letting saturated color overwhelm the frame.
- 01
Set Frames Either Side by the desired visible length of the light trace.
- 02
Compare Luma Threshold on bright sources: an overly broad range quickly turns highlights into dense streaks.
- 03
Lower Chroma Threshold separately if neon or RGB lighting leaves an excessively saturated color mass.
- 04
Set final Blend at real playback speed, then verify after encode.
Title or graphic element
Use Smear as a graphic treatment while preserving text or shape readability.
- 01
Check that the temporal window does not cross a hard graphic change or edit point.
- 02
Increase Frames Either Side only while the primary silhouette remains readable.
- 03
Use thresholds as selective gates: bright text and a saturated logo may need different restrictions.
- 04
If you need explicit discrete echoes with transform control, compare Motion Trails; Smear does not replace its copy pipeline.
Stress-test before delivery
Find temporal artifacts that a still frame can hide.
- 01
Check acceleration, direction changes, and occlusion at 100% playback speed.
- 02
Inspect frames around edit points: the symmetric window should not pull unwanted content from an adjacent shot.
- 03
Check bright and saturated details separately; the thresholds should be the controls limiting their contribution.
- 04
Make a representative delivery encode and judge the smear after compression and scaling.
05CHOOSE THE RIGHT TEMPORAL TOOL
Directional blur, copy echoes, smear, and held cadence are different temporal designs.
Choose by the structure you want to see. Smear is strongest when direct neighboring-frame accumulation is the design and Luma/Chroma selection is enough control.
| FX | When it fits |
|---|---|
| Motion Blur ↗ | When you need directional shutter-like blur with motion estimation, Motion Range, Blur Direction, and Granularity instead of direct neighboring-frame blending. |
| Motion Trails ↗ | When distinct frame copies should remain visible and need Dropoff, Pan/Zoom/Rotate, compositing gamma, and border behavior. |
| Smear | When you want direct temporal smear from a symmetric frame window with independent Luma/Chroma contribution thresholds. |
| Stop Motion ↗ | When the goal is stepped temporal cadence through held/repeated frames rather than accumulation of neighboring samples. |
06READ THE ARTIFACT BEFORE MOVING A SLIDER
Ghost spacing, bright streaks, color drag, edits, and dirty playback point to different causes.
Troubleshooting is quick once temporal duration, luminance contribution, saturation contribution, and final mix are kept separate.
01The subject splits into several readable positions+
Likely cause: Frames Either Side is too large for the motion speed, acceleration, or trajectory change.
Fix: Shorten the temporal window first. Blend does not remove temporal separation; it only makes all ghosts less visible.
02Bright lamps and windows create heavy streaks+
Likely cause: Luma Threshold admits too broad a bright range into temporal accumulation.
Fix: Lower Luma Threshold while preserving the desired Frames Either Side for the rest of the tonal range.
03Neon or RGB turns into a colored mass+
Likely cause: Chroma Threshold is too high for the saturated regions in the scene.
Fix: Restrict Chroma Threshold independently from Luma Threshold; do not lower the whole Blend if the tonal smear is already working.
04An adjacent shot leaks into the effect near an edit+
Likely cause: The symmetric temporal window crosses the edit boundary.
Fix: Reduce Frames Either Side near the edit point, process shots separately, or animate the effect around the cut.
05Blend has to be pulled almost to zero+
Likely cause: The upstream setup is too aggressive: the window is too long or the thresholds admit unwanted pixels.
Fix: Return Blend to a useful level, fix Frames Either Side and the contribution gates, then dose the result again.
06The still looks fine but playback looks dirty+
Likely cause: Temporal rhythm, occlusion, and direction changes cannot be judged from one frame.
Fix: Approve Smear in motion: loop the difficult section, use 100% playback speed, and check a representative delivery encode.
07BEFORE DELIVERY
Approve temporal length, contribution gates, edit boundaries, and encoded motion.
A still frame can look elegant while the same Smear pulses, doubles, or contaminates an edit in motion. Playback is part of the effect evaluation, not an optional final check.
08FAQ
Practical Smear questions.
How is Smear different from Motion Blur?
Smear directly blends a chosen number of frames before and after the current frame and filters contribution with Luma/Chroma Threshold. Motion Blur uses motion-estimation controls to build directional blur; it is a different temporal model.
What does Frames Either Side = 5 mean?
Five frames before and five frames after the current frame participate in the calculation. It is the captured UI state in the screenshot, not a universally correct value.
Do the thresholds change smear strength?
Not directly. They change which pixels are allowed to contribute: Luma by brightness and Chroma by saturation. Blend controls the final overall dosage.
Why should Smear be judged in playback?
Because artifacts depend on relationships between neighboring frames: speed, occlusion, direction, and edit boundaries. A single frame cannot reveal temporal cadence or how ghosts change over time.
When is Motion Trails a better choice?
When you need explicitly readable copies, decay, and geometric separation with Pan/Zoom/Rotate. Smear is simpler: it builds direct temporal accumulation and limits contribution with thresholds.
Sources and boundaries
Control names and interface states are anchored by four native Resolve screenshots stored in this project and Blackmagic’s documentation of the Smear temporal effect. The live hero is an editorial teaching proxy: it deliberately exaggerates symmetric temporal sampling and threshold gating and does not claim to reproduce Blackmagic OFX internals, exact threshold math, color management, or renderer precision.
Verify exact performance and behavior in the Resolve build you use. This page documents visible controls and a repeatable evaluation workflow; it does not reverse-engineer the OFX implementation.