| 摘要 |
<p>Photographic base paper (10) has a face side waterproof coating which is a co-extruded layer structure of at least a pigmented core layer (P) and top surface layer (E) of polyethylene. The thickness of layer (E) is no more than 12 mu m. The pigment content in the face side coating is at least 2 gm-2 and it is distributed such that the proportion by weight of pigment in the core layer is at least 1.75 times as great as the proportion by weight of pigment in the top surface layer. For optimum photodefinition (image sharpness) the top surface layer should be free of pigment, but as thin (1.5 to 3 mu m) as possible. The pigment is preferably TiO2.</p> |
