Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Remove Color Matting

From: After Effects: Insight into Effects

Video: Remove Color Matting

A major part of mastering After Effects is mastering the subject of Alpha channels. In particular, knowing how to solve problems with Alphas when they come up. Now one common problem is if you have an object with anti-aliased or partially transparent edge and part of the background color from behind that object has crept into that edge. Your first recourse is always go to the Interpret Footage dialog and set the Premultiplied pop-up to match the color of that background. But if that doesn't work, there is a plug-in effect, Remove Color Matting, which may also solve your problem.

Remove Color Matting

A major part of mastering After Effects is mastering the subject of Alpha channels. In particular, knowing how to solve problems with Alphas when they come up. Now one common problem is if you have an object with anti-aliased or partially transparent edge and part of the background color from behind that object has crept into that edge. Your first recourse is always go to the Interpret Footage dialog and set the Premultiplied pop-up to match the color of that background. But if that doesn't work, there is a plug-in effect, Remove Color Matting, which may also solve your problem.

Here is an object from the stock footage library that has an Alpha channel, but which has a little bit of an issue with the white fringe around parts of its body. I'll zoom in so you can see this in more detail. You see a little bit of white there and little bit white edge around here. I want to remove this white fringe. I will back down to 100% for now. Now I suspect since fringe is white that this was shot on a white background, I'll double-click it to open it up in its Layer panel and I'll set this to RGB Straight. It says take the Alpha channel out of the equation, show me just the color channels, now behold it is shot against the white background.

To get rid of that fringe, I'll select my layer and apply Effect > Channel > Remove Color Matting. Now Remove Color Matting defaults to attempting to remove black from an object and you will see it actually made this edge worse. Before, after. What you need to do is to enter the correct background color into Remove Color Matting. In this case I've already identified there was white background, I'll click OK and now you will see that my edge, my white fringe, has disappeared. Before, after. I'll zoom in again so you can see this in greater detail.

Here is the base. Before and after. Quite a nice improvement. Now another case where this comes up is if someone supplies you stock footage that has the Alpha channel separate from the actual image. Here is footage of the gun being fired and here is the separate matte that's been supplied by the stock footage house. You will see they have done a nice favor here cutting out the gun and attempting to reduce the black background that's in it that flame. To marry these two layers together, I need to bring up the Track Matte panel; F4 toggles between Switches and Modes and set the bottom, the footage to use the luminance of the Matte layer to cut it out and now I have my muzzle flash against an Alpha channel. There it is against the black background.

This looks pretty good so far but let's say I need to composite this against something else, maybe something with a white background. Now I'm seeing some of that black background from the original footage creep into and contaminate the edges of this muzzle flash. Well again, I'll use Remove Color Matting to attempt to fix this. In this case, it's default to black, it wasn't correct, because the footage was shot against and you can see where it's cut the black out, left me with just color; before and after. So this is the case where it works really well.

By the way, this would not have worked if I attempted to apply it back in my original source footage. I'll set my background color to white, OK, select my footage layer and apply Effect > Remove Color Matting, no effect. I'll select my Matte layer and apply Remove Color Matting, no effect. Remove Color Matting needs to work on something with an Alpha channel and this stock footage doe not have an Alpha channel. It fills the whole screen. Therefore, I needed to have the two in their own comp with Luma Matte applied creating their own alpha in this pre- comp and take that bundle and put it into a second composition to Remove Color Matting to form this magic.

I am running After Effect CS4, so I'll tab the Shift key to bring up the mini flowchart and you will see on my little stack on my two channels with the separate Alpha go into this Remove Color Matting comp and that's where I'm applying my effect. Now Remove Color Matting is good for solving problem with your source, but sometimes effects can introduce problems with the Alpha channel. To learn how to solve those, go watch the third movie on Channel Combiner. We'll talk more about Premultiplied and Straight Alphas.

Show transcript

This video is part of

Image for After Effects: Insight into Effects
After Effects: Insight into Effects

47 video lessons · 10301 viewers

Chris Meyer and Trish Meyer
Author

 
Expand all | Collapse all
  1. 2m 6s
    1. Welcome
      2m 6s
  2. 7m 27s
    1. The Effects & Presets panel: finding effects
      2m 42s
    2. The Effects & Presets panel: animation presets
      4m 45s
  3. 1h 24m
    1. Bilateral Blur
      5m 30s
    2. Box Blur
      5m 33s
    3. CC Vector Blur
      6m 18s
    4. Creative Channel Blur
      2m 2s
    5. Corrective Channel Blur
      1m 47s
    6. The pros of Compound Blur
      4m 35s
    7. The cons of Compound Blur
      3m 3s
    8. Directional Blur
      2m 35s
    9. Fast Blur and Gaussian Blur
      5m 16s
    10. Lens Blur: iris effects
      6m 17s
    11. Lens Blur: depth maps
      4m 41s
    12. Overview of Radial Blurs
      4m 16s
    13. Radial Blurs shootout
      3m 29s
    14. Reduce Interlace Flicker
      4m 12s
    15. Corrective Smart Blur
      4m 26s
    16. Creative Smart Blur
      7m 40s
    17. Unsharp Mask theory
      5m 5s
    18. Unsharp Mask and Sharpen
      3m 59s
    19. Unsharp Mask power tips
      4m 14s
  4. 41m 5s
    1. Overview of Calculations
      3m 55s
    2. Creative Calculations
      3m 32s
    3. CC Composite
      4m 54s
    4. Overview of Channel Combiner
      2m 49s
    5. Channel Combiner and color space
      3m 56s
    6. Channel Combiner and transparency
      4m 0s
    7. Remove Color Matting
      4m 24s
    8. Set Matte vs. Track Mattes
      6m 45s
    9. Set Channels and Shift Channels
      2m 0s
    10. Solid Composite
      4m 50s
  5. 1h 1m
    1. Auto Color vs. Auto Levels
      6m 21s
    2. Auto Contrast vs. Auto Levels
      4m 44s
    3. Channel Mixer
      5m 34s
    4. Corrective Color Balance
      8m 15s
    5. Creative Color Balance
      3m 19s
    6. Color Stabilizer
      4m 51s
    7. Overview of Colorama
      7m 40s
    8. Tinting with Colorama
      5m 48s
    9. Colorama and color cycling
      3m 12s
    10. Hue/Saturation tips
      5m 4s
    11. Hue/Saturation vs. Color Balance
      2m 17s
    12. Tint vs. Tritone
      4m 34s
  6. 14m 40s
    1. Compound effects
      5m 43s
    2. Grayscale shootout
      6m 45s
    3. Repeat Edge Pixels
      2m 12s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ .

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed After Effects: Insight into Effects.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member ?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferences from the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Your file was successfully uploaded.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.