Change color of Standard Assets Vignette

Hello,

I plan to use Vignette and Chromatic Aberration from Unity Standard Assets in my game, but I have encountered a problem. I would like to change color of vignette from black to blue, but after scanning through the script and shader, I still can't find any place I could do that. So my question is: how to change color of vignette?

I would be very grateful for help.