Demo 31 - Sepia with final color

Shader "Custom/FinalColorSepia"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _SepiaIntensity ("SepiaIntensity", Range(0, 1)) = 0
    }

    SubShader
    {
        Tags {"Queue"="Geometry" "RenderType"="Opaque"}

        CGPROGRAM
        #pragma surface surf Lambert finalcolor:SepiaColor

        struct Input {
            float2 uv_MainTex;
        };

        fixed _SepiaIntensity;

        void SepiaColor(Input IN, SurfaceOutput s, inout fixed4 col) {
            fixed3 c = col;
            c.r = dot(col.rgb, half3(0.393, 0.769, 0.189));
            c.g = dot(col.rgb, half3(0.349, 0.686, 0.168));
            c.b = dot(col.rgb, half3(0.272, 0.534, 0.131));
            col.rgb = lerp(col, c, _SepiaIntensity);
        }

        sampler2D _MainTex;

        void surf(Input IN, inout SurfaceOutput o) {
            o.Albedo = tex2D(_MainTex, IN.uv_MainTex).rgb;
            o.Alpha = 1.0;
        }

        ENDCG
    }

    FallBack "Diffuse"
}