There are many advantages to coating your inkjet prints. Firstly,
coatings provide protection from fingerprints, atmospheric pollutants,
UV light, moisture, and help provide resistance to scuff marks on
prints made with pigment inks.
Further, Wilhelm Imaging,
the only real authorities on the issue, indicate that coatings can
seriously increase the longevity of your prints, especially a concern
with dye based inkjet printers .Another reason to coat prints is to
reduce bronzing and gloss differential - in most cases, coating your
prints will eliminate all but the most severe problems.
Protective Spray is the classic inkjet print coating, suitable for all
papers/canvases, except super high gloss papers. It is a very thin
coating and essentially invisible.