A firm's public relations can contribute to the success of its advertising if the public relations helps to create an image of the firm that is compatible with the advertising.
For example, in the US, McDonald's advertisements project the image that McDonald's is a place where families can relax and be happy together. Therefore, McDonald's public relations should work to make sure that people do see McDonald's in that way. They must do things like publicizing things that McDonald's does to help families and communities. They must make sure that the firm does not get involved in any scandals and does not treat anyone badly so as to look unfriendly.
Public relations must project an image of the firm that matches up with its advertising. This helps the advertising and the firm be more successful.
Public relation can have a good impact on the adevertising. It is considered to be a good form of advertising. As it can be seen bymany people not only the target audience but others as well and it could be persuading for the consumers to buy the certain product.
But whatsoever it does have a negative side because it might not be seen by the main target audience therefa waste of money therefore cost of the buisness would rise.
Therefore i think its not always successful to use public relation but only up to a certain extend.