There was a time when the careers of Augustus Wall Callcott and Joseph Mallord William Turner were quite similar: painting style, motives, clients.

But one of them started experimenting, developing something special, risking his reputation and income, and is now considered one of the most important maritime painters of all time. “He is known for his expressive colourisations, imaginative landscapes and turbulent, often violent marine paintings.” Says Wikipedia.

On the Wikipedia page of the other you can just read: “… was a bristish landscape painter”