Here's an example of how to "brighten" specularity in Carrara with the Shaders. While Carrara doesn't have that control via the lights directly, you can acheive the same effect by increasing the Highlight channel beyond the default 100. Additionally, if you use the Add operator, you can throw in some color to. Now if brightening is not your goal just let us know and we'll see what we can figure out! :D Mark