In the past I had developed several plugins for FCP X and Motion 5, but they used some outdated technology by today’s standards. I am currently working on bringing them forward to modern standards and will be rereleasing them as they are finished on the Mac App Store.
Here is what’s available:
eggBW
Using eggBW, you can quickly and easily make much more interesting black and white video than simple desaturation. eggBW goes beyond simply separating the RGB channels for mixing and instead analyzes each pixel to weigh its value toward Red, Yellow, Green, Cyan, Blue, Magenta, and Neutral colors, then uses these weights combined with your input to create the resulting black and white image.
Once everything is mixed, eggBW includes some colorization options including the very unique Tint Complement colorization method. This method tints shadows with the complement of the selected tint color using a very careful application curve.
This allows for more creative control over the contrast and focal points of your black and white images.
eggBW is tested compatible with FCP X as old as 10.4.3 and Motion as old as 5.1.2. OS requirement is macOS 10.13 and later. It is likely compatible with older versions of FCP X and Motion, but is untested.