trim colors with curves efx

[p***@adobeforums.com]

Hello Group
How do I trim colors with curves efx without adding a new keyframe between 2 keyframes TX

[p***@adobeforums.com]

Hello Andrew and group,
I have a QT clip of 21 scenes and I want to mark the ins ad outs. Then I want to change the color of every scenes "SEPARATELY" using curves, levels and saturation effects and I'd like to be able to park on a frame of my choice anywhere between the ins and outs to adjust the colors. The ins and outs don't have to be keyframes is there is a better way for marking the 21 shots. Also can I make color dissolves between 2 scenes. TX for your help
PS: I only have AE on my system.