51. Alpha

It’s been a while since I up-dated the blog, the reason is quite simple, I’m back at work.

My real work that is… After (almost) finishing the animation, I needed to go back to work to save money to be able to finish the compositing and music of the film.

The compositing is when you add up all the layers of animation to create the final picture. It’s usually (in my case) the main character on top of the background, but it can be much more complex, with camera moves, sfx (like rain or fire), depth of field, etc.

BG020 + DE_01_00_JIM_0001  =


To be able to add the character on top of the background, each frame of animation needs an Alpha. An alpha is a black and white pictures that tells pictures where to be transparent, white is not transparent and black is fully transparent.


The checker board is where I want the drawing to be transparent.

Jimmy Alpha

There are various techniques to create a drawing’s alpha, in my case the line of the drawing are not closed so it makes it quite hard to use automatic techniques, so I decided to draw each alpha in photoshop. To do so I created a script that pre makes the alpha (using the magic wand) and I would correct it by hand, then save the picture as a png, which handle the transparency very easily. If you want to know more about the script gimme a shout, I’ll be happy to send it to you.

The whole process is quite short (1 min per drawing), but because you have to do it for each drawings, and I am working with big files (long saving time), it adds up to quite a lot of hours.

It took me around 3/4 week to do all the shot, I did that after work, witch doesn’t speed up the process at all, the good new is that every shot I animated so far have an alpha now, so I can work on compositing the shots.

As a little reward for finishing all the alpha, and as a joke, I edited a fake trailer for the film, it’s put together using the automatic trailer maker that comes with iMove, its stupidly easy to do and takes about 5 minutes and here it is:

As a disclaimer, those are just work in progress.