3D Studio MAX Tutorial Bluescreen 101

Using Premiere or the standard edition of After Effect.

Picture 1

The goal of this tutorial is to create a moving object/person that can then be pulled from the background and placed into another scene. This is not unlike selecting a part of an image in Photoshop with the Magic Wand tool and pasting the portion onto another picture. The difference with video is that the colour in every frame of your video must be pulled rather than just a single image. While there are great plugins, such as Ultimatte to help you complete professional grade projects, this tutorial will only cover tools that come standard with your Adobe After Effects or Adobe Premiere product. In other words, this is for those who are making their effects on the cheap.

This tutorial assumes that you know how to start a New Project in Premiere and a New Composition in After Effects. The Production Bundle is not needed to complete these instructions.

You will be introduced to the following concepts and tools:

  • Bluescreen
  • Alpha Matte
  • Masks

    For this tutorial miniDV footage was used and captured using a Firewire/IEEE 1394/iLink connection. You can still complete this tutorial using anologue capture, but you are hoping for the greatest colour consistency and analogue does not always hold up.

    Final Note: Avoid wearing blue during filming. It will become invisible when compositing.


    Pre-Filming: Things to think about before filming

    Blue Screen

  • When looking for a bluescreen to film against there are many options, however, a fabric is best. It can be draped over odd shaped objects and easily transported to different locations. If you decide to use fabric, iron out as many of the wrinkles as possible. Any hard shadows will be black, not blue, and will not be keyed out once you apply the bluescreen technique.

  • In ideal situations, you will be able to light your background seperately from your talent. Unfortunatly, this is not always an option and extra care must be taken to avoid unintended shadows directly behind the talent. The above graphic shows many shadows caused by creases.

  • Finally, if you do not have a bluescreen, or any other coloured screen for that matter, don't forget that any shot taken on a nice clear day with a blue sky in the background will do the trick very nicely.

    Part One: Using Premiere for quick and simple bluescreen

    Composite

    Once the footage is captured to the computer, import the video into Premiere and drag it onto the timeline. Video 2 track or above must be used to obtain the TRANSPARENCY settings required.

    Adobe Premier

    1. Right click on the footage and choose TRANSPARENCY

    2. From the pull down options entitled KEY TYPE, choose BLUE SCREEN

    3. Use the THRESHOLD slider to choose how strongly the blue is pulled form the video.

    4. Use the CUTOFF slider to leave out areas that may have blue in it, but not as strongly as the bluescreen itself.

    5. If you would like to soften the edges, choose SMOOTHING and select low or high.

    6. Once completed, put any video behind the bluescreen image and render for visual check.

    Composite 2


    Part Two: After Effects, Color Key, and Masking

    Using Premiere for bluescreen is a good method for some situations, but really falls apart on others. The problem is that there are bound to be poor lighting conditions on parts of the image, causing unwanted artifacts. Also, some parts of the image being bluescreened are unecessary in the final shot. This is where After Effects can be used to solve the problem.

    Color Key:

    1. Import the bluescreen footage and background footage you would like to use.

    2. Drag the bluescreen file to the timeline

    3. Select the Effect option from the top menu bar and select Keying and finally Color Key

      Color Key

    4. This option menu will allow you to choose one of the shades of blue in the bluescreen in order to remove the colour. Unfortunately, not all of the blue will probably be removed and it will be necessary to reapply the effect and select a different colour blue. For the example pictured above, three blues needed to be keyed out.

    5. Notice that a blue halo seems to surround the talent. This can be removed, to a point, by using the Edge Thin option on the colour that is closest to the talent. By selecting a positive number, you slightly choke the matte and as a result remove the halo, but also shave off part of the talent.

    Masks:

    Masks On

    The footage is now prepared quite closely to what Premiere was able to do earlier. However, the advantage now is that masks can be created to hide the problem areas that cannot be removed with the Color Key process.

    1. Double click on the bluescreened footage. A new window will appear that looks like your original. In fact it is, but you have the ability to create masks.

    2. Choose the Pen tool and click an area around the problem artifacts. You will notice that everything else disappears and all that remains is the artifact.

      Mask Subtract

    3. In the example provided, you would have to change the mask property from Add to Subtract, as shown above. If you do not see the same menu as what is depicted, then you simply need to click the Switches / Modes button at the bottom of the timeline window, or Right Click on the Source Name title and choose Panels | Modes to bring up that menu option.

    4. Do the same for other problem areas.

    What makes these masks even more powerful is that they are animatable. If desired, a mask could have been drawn around the talent, only the above example had very little movement with the masked off artifacts and animating every time the talent moved would have taken much longer.


    As a final idea of what you can produce, I have provided an effect created entirely in After Effects. Masks were used for much more than cropping out artifacts, but shows how far these powerful features can be taken in combination with bluescreen techniques.


  • Author: Jason Brackman
    Reprinted from www.spoono.com