Cellphone Commercial: Greenscreen Removal

Topics Covered in This After Effects Tutorial:

Keying the Backgrounds, Creating a Matte for the Phone Screen

Exercise Preview

Exercise Overview

In this comprehensive exercise, we'll advance your digital compositing skills by tackling one of the most critical aspects of professional post-production: color keying. Working with actual commercial footage from a T-Mobile spot, you'll master the art of cleanly removing both green screen backgrounds and blue screen phone displays across three dynamic scenes featuring our talent, Janet.

This isn't just about clicking a magic wand—professional keying requires understanding color theory, edge refinement, and spill suppression techniques that separate amateur work from broadcast-quality results. The techniques you'll learn here form the foundation of modern visual effects work, from indie films to Hollywood blockbusters. In subsequent exercises, we'll composite your perfectly keyed footage with animated backgrounds and branded phone screen content, creating a polished final piece worthy of your professional portfolio.

Previewing What You'll Make in This Exercise

1. On the Desktop, navigate to Class Files > After Effects Level 2 Class > Cellphone > Finished Clips and double–click Cellphone-Color Keying.mov.

2. Play the video and analyze the following technical achievements:

   • The dramatic comparison between the completed professional-grade color keying and the original raw footage with green screen visible in the bottom-left corner
   • Clean extraction of blue screen content from the phone displays in shots one and two—notice the precise edge detail preservation
   • The cohesive black and white treatment that unifies all footage elements

3. You should still have yourname-Cellphone.aep open in After Effects. If you closed it, re-open it now. We strongly recommend completing the previous exercise (3A) before proceeding, as this builds directly on those foundational skills. If you haven't finished it, follow this recovery path:

   • Open Cellphone-Ready for Greenscreen Removal.aep (from the Cellphone > Finished AE Projects folder)
   • Save the file as yourname-Cellphone.aep in the Cellphone folder

Removing Janet's Background

We'll begin with the most challenging scene—the third sequence where Janet delivers her triumphant "yay" moment, looking up and throwing her hands skyward. This shot tests your keying skills with complex edge detail and motion blur.

1. If you do not have Cellphone-MAIN open in the Timeline already, open it now.

2. In the Timeline, double–click [4-Janet-yay] to open it in a new Timeline tab.

3. Navigate to the beginning of the Timeline. Since this footage will eventually feature a dynamic animated background in the final commercial, achieving a clean key is absolutely critical—any artifacts will be immediately visible against the new background.

4. In the Timeline, select the first layer, [Janet-yay.mov]. It should already be soloed for your convenience.

5. Go to Effect > Keying and examine the available options carefully.

6. After Effects offers numerous keying solutions, from simple color-based keys to advanced algorithms. For professional work, Keylight (1.2) remains the industry standard—it's the same algorithm used in high-end compositing applications like Nuke. This isn't just the most sophisticated option; it's what working professionals rely on for broadcast and film work. Click on Keylight (1.2).

7. In the Effect Controls panel, locate Screen Colour and click the eyedropper tool.

8. Here's a professional technique that many beginners miss: we don't want to sample just a single pixel, which could give us an unrepresentative color value. Press and hold the Cmd (Mac) or CTRL (Windows) key—notice how the eyedropper cursor enlarges. This activates area sampling mode, averaging multiple pixels for a more robust color selection that handles lighting variations across your green screen.

9. Proper sampling location is crucial for optimal results. You want an area that represents the true screen color—not too bright (which might be overexposed) or too dark (which might be in shadow). While holding down Cmd (Mac) or CTRL (Windows), click on the green background to the left of Janet's head as shown below:

   

   Professional Tip: You can also click on the color swatch next to Screen Colour and input a hex code for consistent results across multiple shots. Through testing, we've found that #80B891 delivers excellent results for this particular shot.

10. You should immediately see the green background replaced with a bright magenta color—this indicates successful transparency. If you're seeing a checkerboard pattern instead, click the Toggle Transparency Grid button to switch to solid color preview mode.

11. Now we'll use Keylight's diagnostic tools to refine our key. In the Effect Controls panel, locate the View dropdown and change it to Status.

    Status mode provides a visual diagnostic that's essential for professional keying work. In this view: solid black areas represent perfect transparency, solid white shows completely opaque regions, and gray indicates problematic semi-transparent areas. Your goal is achieving the highest contrast possible—Janet's silhouette should be pristine white while the background becomes solid black.

12. Let's refine our selection using Keylight's advanced controls. In the Effect Controls panel, adjust Screen Balance to 5. Notice how this removes more edge pixels that might belong to Janet rather than the background.

13. Experiment with extreme settings to understand the control's range: try setting Screen Balance to 95. You'll see this aggressively over-selects, removing parts of Janet—clearly too much.

14. Return the setting to 5 for optimal results.

15. For precision refinement, expand the Screen Matte section by clicking the arrow next to Screen Matte.

16. Clip Black and Clip White function similarly to Levels adjustments but specifically for your matte. Increase Clip Black by dragging the value to approximately 16—this forces more background pixels into full transparency.

17. Adjust Clip White to around 49 to ensure Janet's pixels remain fully opaque. This creates the clean separation essential for professional compositing work.

    Note: These values may require fine-tuning depending on your exact eyedropper sampling location and monitor calibration.

18. You may notice green-tinted halos around Janet's silhouette in Status mode—these represent color spill, where the green screen's illumination has contaminated the edge pixels of your subject.

19. Return to normal viewing by changing the View dropdown back to Final Result.

20. Zoom in to examine the transition area between Janet and the background carefully. Professional work demands clean edges, so let's eliminate that problematic green halo.

21. In the Screen Matte section, set Screen Shrink/Grow to –2.5. This contracts the matte slightly, removing contaminated edge pixels.

22. Adjust Screen Softness to 1 to create a natural edge transition. Perfect! Since we'll be converting this footage to black and white, we can accept this level of refinement—the monochromatic treatment will mask any remaining subtle color artifacts.

Color Correcting the Janet Yay Scene to Black & White

Now we'll apply the same stylized black and white treatment used for Gaurav's interview footage, ensuring visual consistency across the entire commercial. This monochromatic approach not only creates a cohesive brand aesthetic but also helps mask any minor keying imperfections.

1. Ensure [Janet-yay.mov] remains selected in your Timeline.

2. Navigate to Effect > Color Correction > Black & White to apply the monochromatic conversion.

3. In the Effect Controls panel, you can fine-tune the black and white conversion by adjusting how different color channels contribute to the final luminance values. Feel free to experiment with these settings to achieve the most flattering result for Janet's skin tones.

4. Enhance the contrast by going to Effect > Color Correction > Levels.

5. In the Effect Controls panel, expand the Levels section. Under the Histogram display, drag the leftmost slider (black point) moderately to the right to deepen the shadow areas and add visual impact.

6. Set the Gamma value to 0.77 to brighten the midtones slightly, ensuring Janet remains the focal point. This completes our work on this dramatic scene!

Keying the Background in the Next Scene

Moving to our second scene, we'll tackle a more complex challenge: creating separate mattes for both the background and the phone screen. This dual-keying approach is essential when you need to replace multiple screen elements with different content—a common requirement in modern commercial work.

1. Return to the Cellphone-MAIN tab to access your main composition.

2. Double–click [2-Janet-phone] to open this scene in a dedicated Timeline tab.

3. In the 2-Janet-phone Timeline, select the janet layer and duplicate it using Cmd+D (Mac) or Ctrl+D (Windows).

4. Rename the duplicate from janet 2 to phone matte—this descriptive naming will be crucial when managing multiple layers in complex compositions.

5. Hide the phone matte layer by clicking its visibility icon . We'll configure this layer specifically for isolating the phone screen—a technique that gives you precise control over multiple screen replacements.

6. Select the janet layer and press I to jump directly to its in point.

7. Apply Effect > Keying > Keylight (1.2) to begin the background removal process.

8. Click the eyedropper next to Screen Colour in the Effect Controls panel.

9. Hold Cmd (Mac) or CTRL (Windows) and sample the green background in the area between Janet's head and the phone—this region typically offers the most neutral lighting conditions.

   For consistent results across multiple workstations, you can input the hex value #418C58 directly, which we've found optimal for this particular shot.

10. Switch the View mode to Status to analyze your matte quality.

11. Set Screen Balance to 5 for optimal subject preservation—this conservative setting ensures we don't accidentally remove any of Janet's edge detail.

12. Expand the Screen Matte section for precision adjustments.

13. Set Clip Black to 26. Don't be concerned if some corner areas remain gray rather than pure black—we'll address these with strategic masking in the next steps.

14. Adjust Clip White to 70 to ensure Janet's silhouette remains solid and well-defined.

15. Now we'll create a garbage matte to clean up any problematic areas. Press Q to cycle through the shape tools. Look in the Tools panel to confirm the Rectangle tool is selected.

16. If the Rectangle tool isn't active, continue pressing Q until it appears (typically three presses if starting from the Ellipse tool).

17. With the janet layer selected in the Timeline, draw a rectangular mask in the Composition panel that generously encompasses Janet's entire performance area—ensure she remains fully within this boundary throughout the scene.

18. Switch to the Selection tool and double–click the rectangle outline to enter edit mode for precise adjustments.

19. Scrub through the Timeline to verify Janet remains within the mask boundaries throughout her performance, adjusting corner points as needed. Your final mask should look similar to this:

    

20. Return the View mode to Final Result to assess your composite. You'll likely notice some green color contamination around Janet's edges—this is color spill that requires additional treatment.

21. In the Screen Matte section, set Screen Shrink/Grow to –2.6 to contract the matte and eliminate contaminated edge pixels.

22. Set Screen Softness to 1 for natural edge transitions.

23. To address remaining color spill in Janet's hair, apply Effect > Keying > Advanced Spill Suppressor—this specialized tool targets color contamination that standard keying can't eliminate.

24. In the Advanced Spill Suppressor section, change the Method to Ultra for maximum spill removal effectiveness.

25. Click the color swatch next to Key Color (to the left of the eyedropper icon).

26. In the Key Color dialog, input #398750 and click OK. This targets the specific green hue contaminating the edges.

27. For additional spill control, return to the Keylight effect's Screen Matte properties and change Replace Method to Hard Colour.

    Some minor green tinting may persist in fine hair detail, but this is acceptable since our final black and white treatment will eliminate any color artifacts.

Creating a Matte for the Phone Screen

Now we'll configure our duplicate layer to create a precise matte for the phone screen replacement—a technique that allows independent control over different screen elements within the same shot.

1. Select the phone matte layer and restore its visibility by clicking the eye icon .

2. Press I to navigate to this layer's in point.

3. Apply Keylight (1.2) to this layer as well.

4. Click the eyedropper next to Screen Colour.

5. Hold Cmd (Mac) or CTRL (Windows) and sample the blue screen area of the phone—this requires precision since phone screens are typically much smaller than background green screens.

6. Change the View mode to Combined Matte for optimal analysis.

   Combined Matte provides a comprehensive view that combines the Screen Matte with any masks and source alpha channels. This black-and-white representation clearly shows your opaque foreground elements (white) versus transparent background elements (black), making it ideal for evaluating screen replacement mattes.

7. Scrub through the Timeline with the playhead. Solid black areas indicate perfect transparency—exactly what we want for screen replacement. Gray or patchy areas signal inconsistent keying that requires keyframe animation to track color changes over time.

8. Return to Final Result view and temporarily disable the effect by clicking the fx icon next to Keylight (1.2) in the Effect Controls panel.

9. Navigate to 2;23 (just before the phone rotates away from camera) with the phone matte layer selected.

10. Click the stopwatch next to Screen Colour to enable keyframe animation—this allows the key to adapt as lighting conditions change throughout the shot.

11. Move to 2;26 in the Timeline.

12. Click the eyedropper and, while holding Cmd (Mac) or CTRL (Windows), sample the phone's blue screen at this new time position.

13. Continue to 2;28 in the Timeline.

14. Repeat the sampling process: grab the eyedropper and Cmd/CTRL-click on the phone screen to create another keyframe.

15. Move to 3;00 for the final keyframe.

16. Perform one final sampling of the phone screen using the same eyedropper technique.

17. Re-enable the Keylight effect by clicking the fx icon .

18. Switch to Combined Matte view to evaluate your animated key results.

19. Scrub through the Timeline to verify consistent keying quality across all keyframes.

20. Set the playhead to 2;29 to define the end of this matte's usefulness.

21. Trim the phone matte layer to end one frame later by pressing Opt–] (Mac) or ALT–] (Windows).

22. Hide the phone matte layer by clicking its visibility icon .

    With visibility disabled, this layer no longer affects your current composite but remains ready for use in upcoming exercises. You'll notice the background keys cleanly while the phone screen shows artifacts from our Janet layer's Keylight settings—this is exactly as planned. In future exercises, we'll use 4-point tracking combined with this phone matte to replace the original blue screen with branded content.

Color Correcting the Janet Phone Scene

Let's complete this scene by applying our signature black and white treatment, maintaining visual consistency with the previous scene while preparing the footage for final composition.

1. Select the janet layer and confirm it's visible .

2. Apply both the Black & White effect and Levels effect in sequence.

3. In the Effect Controls panel, configure the Levels with these optimized values for this particular shot:

   Input Black:	7
   Input White:	203
   Gamma:	1.14

   These settings ensure optimal contrast while maintaining detail in both highlights and shadows.

Keying the Background in the Close up Shot

Our final scene presents the ultimate test of your keying skills—a tight close-up shot where every detail matters. Close-up work demands absolute precision since any artifacts will be magnified on screen.

1. Return to the Cellphone-MAIN tab to access your primary composition.

2. We'll be working with the [3-Janet-closeup] composition. Double-click it to open in a new Timeline tab, where we'll apply the same professional keying techniques to this intimate performance moment.