Many logo designs contain gradients of colours that blend into each other. The technique of using colour gradients within a Logo Design is one that works well but often people try to create more obvious blends of colours with harsher contrasts. There are occasions when this can work but usually it is best to be more subtle with a logos gradient fill colours as high contrast colour gradients can make a logo look a little dated.
The image above features two examples of logos the first logo has a harsh gradient that provides a high contrast but is not really very professional in terms of its appearance. the second logo features a very subtle gradient that helps to give the logo a nice subtle blend of colours.