I have a huge AFX project, many comps with multiple uses of particular with "color over life" using a gradient. Is there a way to use expressions and a color control layer to affect each of the colors in the gradient itself? Every time our art director changes his mind on color, I have to go in and edit 3-4 layers in each of 70 comps. I use color control layers for anything that's one color, or a ramp, but in Particular, I cannot attach an expression to color chips in the gradient. Any ideas?
I'm afraid there is no way to use an expression for the Color over Life property. However, (and hopefully this is what you are doing now) you can copy/paste the entire Color over Life gradient between instances of Trapcode Particular. Just hit the little COPY icon in the right of the color UI, then hit PASTE on the other instances.
If you are using Custom particles they could all be using the same precomp, so there would only be one place to change all colors. If your particle is a simple sphere/glowsphere or star you could easily create a custom particle instead. Then use the Start at Birth - Stretch mode to make the particle precomp stretch to particle life.
Yeah, sucks big time. Depending on the type of particle system you wanna create, you might also have success with other tools. I've created some interesting setups in the past using Digital Anarchy's Text Matrix with dingbat fonts and just recently also discovered that Particle Playground isn't that useless after all... ;o)