Working with text...changing color progressively

Seeking some "how to" tips. Let's say I have a line of black text. Over the next 10 seconds, I wish to change the text color to blue, one letter at a time, BUT not one full letter at a time. Starting from the left, I'd like to have the color blue sweep across the letters from left to right, as outlined in the illustration. Can this animation be done in FCPX, and if so how do I do it?

PS: I tried a basic method with the text as Stencil Alpha and then animating a white then blue object underneath, and that does work, except outside the text the background is blocked off of course...and that is not what I want. Also discovered a text plugin I am using doesn't respond to Stencil Alpha anyway. But right now, bringing it into the process only makes things even more complicated. Still trying to figure out how to have the text change as described, but not block the back ground image in the process.

EDIT: Ah ha, got the basic text working. All I had to do, so it didn't block the background, was turn it into a Compound Clip. No success yet with the plugin text yet, but will leave that for another day.

One method that could work is to create two versions of the text. One black, and one blue. Place the blue one on top. Use the crop sliders to crop out the blue text entirely, leaving the black one visible. Then using the crop keyframes, reveal the blue text over the next 10 seconds. You could also do this with a mask and feather the mask so that it is not a hard line but a more organic soft edge.

bjrE wrote:

One method that could work is to create two versions of the text. One black, and one blue. Place the blue one on top. Use the crop sliders to crop out the blue text entirely, leaving the black one visible. Then using the crop keyframes, reveal the blue text over the next 10 seconds. You could also do this with a mask and feather the mask so that it is not a hard line but a more organic soft edge.

Thank you! Two useful suggestions and I will try them as well. Much will depend on how they behave in a compound clip after masking or cropping, but theoretically they should work. Obviously now, more than one way to achieve this. Cheers!

The suggestion by bjrE is a good one. In fact, many commercial animated titles that are designed in Motion make us of this technique. We developed several Patriotic title and background templates for a client using exactly these methods.

dgwvideo wrote:

The suggestion by bjrE is a good one. In fact, many commercial animated titles that are designed in Motion make us of this technique. We developed several Patriotic title and background templates for a client using exactly these methods.

Thanks for your input; good to know. Actually I thought of using Motion, but wanted to see what I could do in FCPX. Cheers!