A knife of some sort is essential in the artist's and designer's tool kit and can, in many practical ways, be as creative a tool as a pencil or precision drawing instrument. At least two types of knives are required for the many different cutting and trimming tasks that are likely to take place in the studio.
Firstly, an art knife carrying a fine extended blade with a very sharp point is necessary for the accurate and detailed cutting of items during paste-up. This knife should be both light and maneuverable enough to be used with the necessary delicacy and precision. To maintain clean, neat artwork a knife should remain sharp at all times - change the blade as soon as it loses its first keenness. Although a long, pointed blade is generally the most useful, other shapes can be more convenient for certain jobs. A rounded blade, for instance, copes far better with cutting curves, while one with a narrow end is good for particularly small shapes.
The second essential type of knife is a general utility or craft knife with a broader blade. This is used for cutting heavy pages, board and tough craft materials. Some feature a plastic body and screw mechanism that carries a retractable, segmented, snap-off blade for quick access to a fresh blade. The shorter and stumpier the body of the knife, the more pressure can be applied upon it, but for really heavy-duty use a good quality, solid metal bodied knife with a screw-in blade is probably a better choice. These are much more suitable for work on very difficult surfaces since they offer a higher degree of safety.