--- title: "BLUR BACKGROUND in Davinci Resolve | Davinci Resolve Tutorial" author: "Sarah Williams" category: Tutorials excerpt: "Learn how to blur the background of your video and simulate a shallow depth of field in DaVinci Resolve using Power Windows, Qualifiers, and the Gaussian Blur tool." --- To blur the background of a video in DaVinci Resolve, you must isolate your subject using a Power Window or the Magic Mask on the Color page, invert the selection, and apply a heavy blur to the unmasked area. By combining a tracked mask with the Gaussian Blur or Lens Blur Resolve FX, you can artificially create a shallow depth of field (bokeh) that separates your subject from a distracting environment. ## What is artificial background blur (depth of field)? A blurred background (shallow depth of field) is a photographic technique where the subject is in sharp focus while the environment behind them is out of focus. This effect is naturally achieved in-camera by using a fast lens (e.g., f/1.8 or f/2.8) and a large sensor. However, if footage was shot on a smartphone, a drone, or with a closed aperture, the entire image will be in focus, making the scene look flat and cluttered. DaVinci Resolve allows you to artificially recreate this cinematic look in post-production by masking the subject and softening the remaining pixels. ## How to isolate the subject using a Power Window? The first step to blurring the background is telling DaVinci Resolve what *not* to blur. 1. **Navigate to the Color Page:** Select the clip you want to blur on the Edit timeline and click the "Color" tab. 2. **Add a Serial Node:** Right-click the node tree (or press `Option+S` / `Alt+S`) to create a new node. 3. **Draw a Power Window:** Click the "Window" icon (the circle with a dot) in the middle toolbar. Select the "Pen" or "Curve" tool. 4. **Mask the Subject:** Click around your subject to draw a tight mask. If they are moving, you do not need to be pixel-perfect yet. 5. **Soften the Edge:** Increase the "Softness" sliders (Inside, Outside, and Edge) in the Window panel to blend the harsh edge of your mask into the background. ## How to track the mask to a moving subject? If your subject moves, the mask must move with them, or the blur will quickly cover their face. 1. **Open the Tracker:** With the Window node still selected, click the "Tracker" icon (crosshairs) next to the Window icon. 2. **Position the Playhead:** Move the playhead to the frame where you drew the mask (usually the beginning or middle of the clip). 3. **Track Forward/Backward:** Click the "Track Forward" (play icon) and "Track Reverse" buttons. DaVinci Resolve will automatically analyze the footage and stick the mask to your moving subject. ## How to apply the blur to the background? Once the subject is perfectly tracked, you must invert the mask and apply the actual blur effect. 1. **Add an Outside Node:** Right-click the node containing your tracked mask and select `Add Node > Add Outside` (or press `Option+O` / `Alt+O`). This creates a new node that affects *everything except* the masked subject. 2. **Open the Blur Tool:** Select this new Outside node. Click the "Blur" icon (the teardrop) in the middle toolbar. 3. **Increase the Radius:** Drag the "Radius" slider up significantly. The background of your video will instantly become blurry, while your subject remains sharp. 4. **Use Lens Blur (Studio Only):** For a more realistic, cinematic bokeh effect, go to the Effects library (top right), search for "Lens Blur" (`Resolve FX Blur`), and drag it onto the Outside node instead of using the standard Gaussian blur. Adjust the "Iris Shape" and "Blade Count" to simulate real camera optics. ## How to refine the blur edge using the Qualifier? A simple Power Window often creates an unnatural "halo" effect around the subject, especially if the background is complex or the subject has frizzy hair. To refine the edge of the blur, combine the mask with a color key: * **Open the Qualifier:** Select your original Window node. Click the "Qualifier" tool (the eyedropper). * **Sample the Subject:** Click and drag the eyedropper over your subject's skin tones and clothing. * **Refine the Key:** Adjust the Hue, Saturation, and Luminance sliders until only the subject is solid white in the Highlight view (press `Shift+H`). * **Update the Outside Node:** The Outside node will automatically update to use this refined key, creating a much tighter, more realistic boundary between the sharp subject and the blurred background. ## How to speed up heavy Color page workflows? Tracking masks, applying Lens Blurs, and refining Qualifiers require immense GPU processing and can crash slower computers. Professional editors avoid rendering VFX on footage they won't use: * **Lock the Edit First:** They upload raw footage to [Cutsio](https://cutsio.com) to extract the narrative using AI transcripts and export the selections via XML. * **Import to Resolve:** They import the XML into DaVinci Resolve to establish the structural edit. * **Apply VFX Last:** Only after the timeline is locked do they move to the Color page to track masks and apply heavy background blurs to the specific clips that made the cut. * **Render Cache:** Once the blur is applied, they right-click the clip on the Edit page and select `Render Cache Color Output` for smooth playback. ## Frequently Asked Questions (FAQ) ### Can I blur the background instantly without drawing a mask? Yes, if you own DaVinci Resolve Studio (the paid version). Instead of drawing a Power Window, use the "Magic Mask" tool. Draw a single stroke down your subject, click track, add an Outside Node, and apply the blur. The AI handles the complex edges (like hair) automatically, saving significant time. ### Why does my subject have a glowing halo around them? If the blur bleeds into the subject, your mask is either too large or the "Softness" is turned up too high. Select the Window node, decrease the "Softness (Outside)" slider, and ensure the mask is choked tightly to the subject's body. ### Can I blur the background on the Edit page? While you can drag a Gaussian Blur effect onto a clip in the Edit page, you cannot easily mask out the subject or track them without the robust node architecture of the Color or Fusion pages. Blurring a background requires precise isolation, which is best done on the Color page. By mastering Power Windows, the Tracker, and Outside Nodes on the Color page, you can easily add cinematic depth of field and professional background blur to any shot in DaVinci Resolve.