Outgassing is an issue caused by paint that for many potential reasons has not fully cured. The term refers to gaseous compounds that are released by the paint as part of the chemical process of curing or "drying". The gas passes through the porous surface of the paint until it is dry.
It is often experienced with vinyl emulsions and other acrylic-based paints with a matt finish, such as matt emulsions, but it is also possible with enamel (or oil)-based paints, and automotive paints. The latter may cure faster but still exhibit this phenomenon as they dry. This outgassing is the pungent odours we recognise being given off by the strong oil-based paints.
While paints may be "touch dry" within a matter of minutes, it can take 5-7 days to fully cure, and in some cases as long as 2-5 weeks, especially in humid and damp environments, or outdoors where the paint is exposed to the wind and rain.
This can have serious implications on the quality and durability of vinyl graphic applications. If for example the surface (or substrate) to which the vinyl will be attached is not fully cured, after the vinyl has been applied, the vinyl film may over time be pushed away from the surface by the release of gas. This can result in air bubbles, and in serious cases, an overall bumpy texture to the graphics. Eventually, this may cause peeling and curling or total failure of the sign.
It is therefore essential that, in order to see the best life from the vinyl graphics application, painted surfaces are fully cured (dry) before application is attempted.