After manufacture, the uncoated paper surface may be coated with white clay materials. The clay gives the paper a smooth feel by filling minute valleys in the paper surface. The coating also limits the absorption of inks into the paper. Because the inks stay on the surface of the coating instead of soaking in, the ink looks deeper, sharper, and glossier. However, writing and ballpoint pen inks may take longer to dry on coated paper and can smudge more easily. On coated stock, less ink is needed to achieve the desired visual richness for text, images, and photo’s.
Coatings are offered in a range of reflectivity values including dull, matte, silk, satin, or glossy. Reading long areas of text is easier when printed on dull or matte finishes. After printing images on dull or mat stock, a varnish can be applied to the picture areas to add gloss and make the pictures pop.