Hilton titled many of his paintings simply by the date of their completion so as to emphasise his desire that the work be seen for itself, and not in any representational way. However, by the 1960s he had developed a new kind of figurative language. In his compositions of these years abstract shapes and looping lines often suggest the presence of a figure or landscape, or both. These bold forms are obsessional, recurring constantly in his paintings. Works of this period, such as 'September 1961', are also less densely painted and more atmospheric than earlier works. This could well be the result of his growing sensitivity to his light-filled, airy surroundings.