1. Import your footage: Drag and drop your grainy footage into the Project panel in After Effects.
2. Create a new composition: Right-click on the footage in the Project panel and select "New Composition" to create a new comp with the same settings.
3. Add the "Denoise" effect: Drag and drop the "Denoise" effect from the Effects panel onto your footage in the Timeline panel.
4. Adjust the "Denoise" settings:
* Denoise: Adjust the "Denoise" slider to reduce the graininess of the footage.
* Detail Handling: Choose "Balanced" or "Soft" for a more subtle effect or "Strong" for a more intense effect.
* Blur Quality: Set to "Best" for higher-quality results but slower processing.
5. Optional Blur: If you want more control over blurring, add the "Gaussian Blur" effect to the footage. This allows you to adjust the blurriness and radius.
6. Preview and adjust: Preview your footage and make adjustments to the settings as needed to achieve the desired effect.
7. Export your footage: Once you're satisfied with the result, export your enhanced footage by selecting "File" > "Export" > "Add to Render Queue" and choosing your desired export settings.
Remember that while these techniques can help reduce graininess, they might not completely eliminate it without potentially compromising image detail. Experiment with the settings to find the best balance between grain removal and preserving the footage quality.