セピア調シェーダ作ってみた ref: http://qiita.com/Es_Program/items/d6b504550e34522d62bc

SepiaVF.shader

Shader "Custom/SepiaVF"{
    Properties{
        _MainTex("Main", 2D) = "black"{}
    }

    SubShader{
        Lighting Off

        Pass{
            CGPROGRAM
            #pragma vertex vert_img
            #pragma fragment frag
            #include "UnityCG.cginc"

            sampler2D _MainTex;

            float4 frag(v2f_img i) :COLOR{
                float4 tex = tex2D(_MainTex, i.uv);
                float4 c;
                c.r = tex.r*0.393 + tex.g*0.769 + tex.b*0.189;
                c.g = tex.r*0.349 + tex.g*0.686 + tex.b*0.168;
                c.b = tex.r*0.272 + tex.g*0.534 + tex.b*0.131;
                c.a = tex.a;
                return c;
            }
            ENDCG
        }
    }
}