You are right about the logo changing colours. You may use a bounding box which has a fixed size to avoid this. You cannot have a dynamically sized bounding b

You are right about the logo changing colours. You may use a bounding box which has a fixed size to avoid this. You cannot have a dynamically sized bounding box and still expect the colour to be the same, since the number of bounces since a fixed start time depends on the size of said box.