Surface Finish
A high density paperboard substrate features one or more layers of mineral pigment applied to the surface to reduce ink absorption and increase light reflectance. Usage of gloss coated board ensures that printed imagery retains high color saturation because the ink film stays on top of the coating rather than penetrating the underlying fibres. This material provides the structural stiffness required for premium secondary packaging.
Optical Property
Specular reflectance levels reach their peak when the coating formulation includes fine clay or calcium carbonate particles that are polished during the calendering process. A gloss coated board achieves a smooth topography that minimizes light scattering at the boundary between the air and the coating layer. High gloss levels often exceed forty percent on a seventy five degree gloss meter reading.
This measurement determines how crisp the highlights appear in halftone printing.
Ink Performance
Rapid solvent evaporation occurs on these surfaces during the drying phase of the offset lithography process. The chemical composition of the coating determines how well the gloss coated board accepts UV cured inks or water based varnishes. If the coating is too porous, the carrier oils drain away too quickly and leave the pigment under-bound.
Conversely, a completely sealed surface might lead to set off where ink transfers to the back of the next sheet in the delivery pile.
