| 摘要 |
<p>PURPOSE:To improve the glossiness and quality of a substrate for photographic printing paper and to prevent uneven coating with an emulsion even at the time of high-speed coating by specifying the average roughness SRa of the central face represented by three-dimensional surface roughness, the height SRp of the peaks of the central face and the depth SRv of the valleys. CONSTITUTION:The fine-grained surface of a substrate for photographic printing paper is amorphously and irregularly formed so that 5-20 projections having 3-15 mum difference of altitude are distributed to 3 mm interval. The average roughness SRa of the central face measured with a three-dimensional surface roughness gauge is regulated to 1.0-2.0 mum, the height SRp of the peaks of the central face is regulated to 5-7 mum and the depth SRv of the valleys to 6-9 mum. The glossiness and quality of the substrate are kept optimum and uneven coating with an emulsion is prevented even at the time of high-speed coating.</p> |
