The Scribble Cel

I might be killed for telling you this.. but it's not really a secret, just something that isn't as well known as it should be in the Flash community, and something I'm sure everyone could benefit from. I mentioned it in my New Masters chapter, and teach it in every Flash class I give.

It's an old camera technique from the days of traditional animation and it has many applications. The scribble cel is a technique used to make water glisten with sparkles.. at its simplest, it requires no more than two drawings but in the hands of an experienced FX guy the results can be stunning.

So what is it?
The scribble cel technique gets its name from one of the two drawings.. a page of scribble, which in the old days of traditional cel animation, was inked onto a clear acetate sheet (cel). It has other names, all of which escape me. Yaye for selective memory!

So the two drawings in the Scribble Cel technique are:

1. Scribble
2. Dots

Yes, that's really all you need. Admittedly, this is the most basic implementation of the scribble cel and when you know how it works you can add your own little flourishes to it. Here's the guts of how it worked in traditional camera:

1. Scribble is inked onto a clear acetate sheet
2. Dots become holes punched into black card
3. Bright light is shone behind the black card (coming through the holes)
4. Camera captures this light

Press Play to see the demo:



Right before your eyes, this extremely simple and now very old traditional technique fakes a random glistening effect. The design of the scribble, combined with the design of the dots (holes) can be varied for different effects.

Check the Ween video (previous article). I've used this effect in almost every scene with water in it. Also check my other movies Prowlies at the River, Bitey of Brackenwood and Auld Sage.

How is this done with Flash?
Short Answer: Masking.

In Flash, a mask defines an area through which you see stuff. So we want to see the scribble through the dots. Therefore, the dots will be the mask layer. You then tween the scribble symbol slowly from one position to another. When it's masked, you get the glistening effect.

Although 30 frames makes a very fast glisten cycle, here's what the timeline should basically look like. Then it's just a matter of lengthening the scene to slow it down.



Result:


The animated example above is about 450 frames (18 seconds) in duration so it's very slow and smooth. You can experiment not only with the design of the scribble and the mask, but also with the speed, easing and duration of the tween. Don't forget, a higher frame-rate makes for smoother animation. The above is at 25fps.

Other Applications:
Experiment with the effect and using masking in this way. Another application would be for twinkling stars, glittering sequens on a dress, sparkling dew on a spider web or even some kind of shadow/negative of the effect for some magical spell.

For years I have been trying to find a way to make a windswept grassland effect in Flash, but haven't quite cracked it. If you happen to get something working, I'd love to see it!