[en] By using the standard symmetry reduction method, the gray/dark solitons and periodic waves (gray/dark soliton lattice) are analytically studied for the nonlinear optical media with periodic nonlocal response. It is found that there are two critical points for the quantity $\mathrm{\beta <!--\; ??\; -->}\equiv <!--\; ???\; -->w_m^2/w_0^2$, the multiplication of the square of the wave number (1/w₀) and the strength (w²_m) of the nonlocality both for the soliton and periodic solutions. The soliton solution exists only for β ≤ 1/4 and the soliton is a double well gray soliton for β > 1/8 while it is a single well gray soliton for β ≤ 1/8. The soliton is dark only for β = 1/4, otherwise it is a gray soliton. Similar critical points exist for the gray/dark soliton lattice solutions. (paper)