How can I add expression to the HUE. The colour as seen in the HUE slider starts from blue and ends in teal and starts from blue again. I would like if possible an expression which when the HUE starts again, it can be another colour other than Blue.
You can't. It's a custom UI control that doesn't have any hooks for expressions. You have to use another effect like Fill and address the standard color control in it, meaning you have to re-create the Hue/ Sat functionality using your own formula.
As suggested by Mylenium, you can use any other effects like Fill to drive that. If you want to preserve your saturation and lightness for the base color, then the Color Balance HLS is your best option. You can use the expression into the Hue parameter to control the color ranges.
Hi thanks for the Tip, can you please tell me what expression to code to write here?
You can use a couple of them:
random (a,b) where "a" and "b" are the range of values you want to use
wiggle (a,b) where "a" is how many osicllations per second do you want to use and "b" the magnitude of the values.
Those values depends on the base color you are using. My advice is to use the Color Balance HLS and try to change the HUE parameter till you find the "blues" you need. Then use that value for any of the expressions.