Inside the jacket of a suit, between the outer fabric and the inner smooth lining, there are several layers of fabric to keep the jacket in shape, this layer is called the canvas. The difference between a full canvas, half canvas and fused jacket front is not immediately apparent as this layer is not seen unless the jacket is taken apart. This difference however is crucial in determining the quality, comfort, fit and durability of the garment.
The method of construction which offers the highest level of quality in all aspects is canvas construction. A canvas front jacket has an inner layer of horsehair which floats in between the jacket front and lining. This method of construction offers the highest level of quality for several reasons. Firstly a canvas front jacket offers a level of durability which is unmatched by other types of construction. One of the problems with fused jackets is that over time with regular wear and dry cleaning the fusing has a tendency to shrink or separate from the jacket front which causes unsightly wrinkling and puckering. This will never happen with a full or half canvas jacket as the canvas in not actually attached to the jacket (except at the lapels) but rather floats in between the jacket front and lining. Another benefit of canvas construction is that because of the flexibility of the horsehair canvas the jacket will actually mold to the shape of the wearer and fit better and more comfortably over time.
Canvas construction is a much more tedious and time consuming process than other means of construction (there are over a thousand stitches in the lapel alone which attach the canvas to the jacket front) and as a result this method of construction gives a crispness and fullness to the body of a jacket which is not possible with other methods of construction. The only real difference between full canvas and half canvas construction is that on a half canvas jacket the canvas extends to just below the front pocket and not all the way to the hem as with a full canvas. Half canvas construction is excellent for use in lighter weight fabrics because it creates a lightweight, comfortable jacket but still has the same benefits of full canvas, such as greater durability, pad stitched lapels, etc.