Sun board or Foam board is a very strong, light, and easily cut sheet material used for the mounting of vinyl prints, as backing in framing, and for painting. It usually has three layers — an inner layer of polystyrene foam and a white claycoated paper on the outside.

Nowadays sun board is widely used in India and around the world for large format printing and store branding. Photos or creatives are first printed on a self-adhesive vinyl which is then mounted on to the sun board. This sun board can then be taken pasted on a wall, pillar or other flat surfaces using either double-sided adhesive tapes or nails depending on the surface. The more modern method is to print the sun board directly using a UV flatbed printing machine.

In any large-format printing solution, the recommended image resolution is between 72 to 100 dpi at actual size. It is a myth that your images need to be 300 dpi. That is valid for small format printing (like brochures or catalogs) but for prints which are larger in size and have to be seen from a distance, 72 to 100 is a really good print resolution.