How do you add a gradient to a (bezier) stroke?

Question

I created a stroke with the bezier tool, just two points. I want to have a distinct gradient to the color but I can't figure out how to do it. I added the gradient colorize filter but it doesn't seem to do it. Any advice?

Answer 1

Gradient Colorize works a little differently than you expect.  If you already have a gradient image (any image that has a dynamic range will do) and apply a Gradient Colorize filter, the image will have its colors remapped to the gradient colors based on the luminance levels (0 - 255; color converted to gray/brightness) -- light colors assuming the left end colors in the filter gradient; dark colors assume the colors at the right end.
So, to create a line colored as a gradient, the easiest way is to create a shape, color it with the gradient you want, add an Image mask to it and apply the line to the mask.
OR
you can convert the outline from a solid to Airbrush. In the Style. Go into the Stroke inspector and select Stroke Color Mode > Color over Stroke and select your gradient there (I used one similar to Rainbow). You'll probably also want to tighten up the spacing (in Style) and the Brush Profile (open up the gradient and move the white tab far to the right.)  The problem with Airbrush is the brush dabs are always circles and your gradient will look like a pole:
So the solution to that is to use Brush Type  > Image, draw a small white rectangle or square and drop it into the Brush Source.
There are other ways (involving a replicator -- use your line as the source for Geometry (if it's not a simple straight line); set the color mode to Over Pattern; adjust the Points higher for a smoother effect.)
There's usually more than one way to accomplish things in Motion.