Alpha Transitions of the 30s

How to use an alpha transition in After Effects ?

In this tutorial, you will learn how to use an alpha transition from the DVD Alpha Transitions of the 30s. You can visit Turner Classic Movies, a cool site to vizualise some classics trailers.

01 - First, import as footage TGA sequence from the DVD Alpha Transitions of the 30s. Select the first frame of the folder and click on the radio button Targa Sequence.

fig.1 - Importation of a targa sequence

02 - Now, you must interpret your footage as 24 frames per second : select your sequence then do File>InterpretFootage>Main... In the Frame Rate's section indicate 24. For the remainder, the Pixel Aspect Ratio is Square pixels, no fields.

03 - In the Timeline, place at the top of your two footages, the outgoing (Aircraft01) and the entering (Aircraft02), the targa sequence (AlphaTransSD_[00000-00014].tga).
Duplicate it.
Thus, we'll use the first sequence as the transition, the other as a shadow for a little realism touch.
Rename Layer 1 : SeqTransition and Layer 2 : SeqOmbre.

04 - Select Aircraft02 (outgoing footage), choose Luma Inverted Matte in the TrkMat column and choose Layer>Time>EnableTimeRemapping on SeqOmbre.
Click on the eye of SeqOmbre to view the layer on you viewer and change its blend mode to Multiply.
Apply the effect Fast Blur with those settings:
Bluriness : 15
Blur Dimensions : Horizontal and Vertical
Cochez Repeat Edge pixels

fig.2 - your timeline...

fig.3 - ...and the viewer.

05 - Now, select SeqOmbre and choose Luma Matte in the TrkMat column.

fig.4 - Your timeline at stage 05

fig.5 - Your viewer at stage 05