There are a few things that are important to keep in mind when determining the size of a sign. Cabinet size, visual opening, and face size are all things to be aware of. Flex face cabinets and rigid face cabinets are the two general types of signage that these measurements pertain to.
Flex Face Cabinets
What is a flex face cabinet? A flex face cabinet is a cabinet built with a tensioning system. This tensioning system allows for a flexible face to be stretched inside of the cabinet.
Cabinet Size - This is the overall size of the cabinet's structure from outside to outside.
Visual Opening - Once a flex face is stretched, the visual opening is what remains after the rest has been wrapped into the tensioning system. (Retainers are not necessary with a flex face cabinet, but if there is one, the visual opening will then be the size from inside to inside of the retainer.)
Face Size - The face size on a flex face cabinet will always be larger than the cabinet size. The finish size includes the face size plus the bleed needed to wrap into the tensioning system.
Rigid Face Cabinets
What is a rigid face cabinet? A rigid face cabinet is a cabinet built to hold a rigid face that slides into place and is secured by the retainer. Cabinet Size - This is the overall size of the cabinet's structure from outside to outside. Visual Opening - Rigid face cabinets require a retainer to hold the rigid face in place. The visual opening is the size from inside to inside of the retainer. Face Size - The face size on a rigid face cabinet will always be smaller than the cabinet size and larger than the visual opening. This allows for the face to slide into place inside of the cabinet.
*Note: In some instances, rigid face cabinets may use trim cap to hold the face onto the cabinet. In this situation there is no retainer so the visual opening and face size are the same and slightly larger than the cabinet size in order to fit onto the cabinet.