Sign Industry Lingo
Substrates, Sheeting for Signs and Retroreflectivity Defined
Substrate - the basic material used to construct the sign.
Annodize or alodine aluminum – Refers to a protective coating on the aluminum that will foster painting and will help to prevent oxidation.
Sheeting - the face of the sign that is affixed to the substrate. It is the sheeting that determines the level of retroreflectivity and the durability of the sign. Some type of sheeting is required for a sign to be reflective. For example, most traffic signs and some danger and warning signs are required to be reflective by the Manual on Uniform Traffic Control Devices (MUTCD) and OSHA. See our sheeting page.
Retroreflectivity – the proper term given to the materials that have the ability to return most of the light back to its originating source. This does not mean reflective. Many items are reflective, such as aluminum foil, bike reflectors, etc. But the light that is reflected from these items is scattered in many directions. What is important in retroreflectivity is the ability to refocus the light source back to its originating source.
Types of Substrate and Their Uses
Aluminum - Aluminum is the substrate most frequently used for signs, particularly traffic signs, because it is durable, lightweight, and practically rustproof.
Magnetic - Magnetic signs are used where easy removal from steel surfaces is necessary. They cannot have messages on both sides.
Fiberglass - Fiberglass is frequently used for outdoor signs. It absorbs impact without splintering or shattering and is very durable.
Types of Sheeting and Their Uses
Non-Reflective - used most effectively during daylight hours for signs that do not have to be read at night or in darkened rooms.
Engineer-Grade Reflective – a former industry standard sheeting that was used on most retroreflective signs. Highly retroreflective for signs that must be ready at night or in darkened rooms. In many instances, the new FHWA regulations phase out the use of engineered grade.
High-Intensity (Prismatic) Reflective – Now the industry standard for signs when high reflectivity is needed, such as roadway traffic signage and guide signs. Prismatic sheeting meets all FHWA, MUTCD and OSHA requirements.
Diamond Grade Reflective – Now the industry standard for signs when very high retroreflectivity is needed or desired. Diamond grade excels where difficult roadway conditions prevail such as hills, sharp turns or very poor lighting.