Creating a sail step 1: Masking

One of the things that really sells the effect of the image on the sail is the fact that is ONLY on the sail. I am sure there are better ways to do this but, this is way I do it; in keynote.  Ok pick yourselves back up off the floor and let me finish.  We use keynote for presentation for as few reasons 1) alpha channel 2) odd resolution not a problem (we use 3840x720).  Pro presenter 4 should be able to do this as well but I have not had a chance to really get in to it.  I will warn you in advance there are some techniques I use in the process that will make some purists very upset because I do some things with video that are usually BIG no-no's.


So for this shape I start with a basic 4 to 12 point garbage shape and then manipulate the points to fit.  Usually I start with a black background and I use white filled shape so I can see what I am doing.  Once I have the mask finished I can export it from Keynote as a JPEG.

Garbage mask

Once I have the JPEG out I can bring it back in over an .MOV in keynote and then use the alpha tool to get rid of the mask shape.  

So this part is easy, yet usually a little time consuming because you can't alter and present at the same time.  This means you end up a work flow like this; adjust, present, repeat. Depending on how complicated the shapes are really determines time on this, I think for this project the entire mask took me a little over an hour, but less then two.  Mainly because we had curves.

Making the mask for this project was really the easy part, next I had to making the sail.  I won't lie I wasn't really sure how this was going to work when I sat down to it.  I had to make some stuff up as I went on this one, but the results are tough to argue with.  So next post, making the sail loop video.