Question

How could I implement a bleach bypass shader effect for WPF?
I’m also interested in the possibility of implementing the first two Tehnicolor Film Processes, or any variety that would result in an old film look.

Answer 1

Check out: http://developer.download.nvidia.com/shaderlibrary/packages/post_bleach_bypass.fx.zip

The important part is:

float4 bypassPS(QuadVertexOutput IN, uniform sampler2D SceneSampler) : COLOR
{
    float4 base = tex2D(SceneSampler, IN.UV);
    float3 lumCoeff = float3(0.25,0.65,0.1);
    float lum = dot(lumCoeff,base.rgb);
    float3 blend = lum.rrr;
    float L = min(1,max(0,10*(lum- 0.45)));
    float3 result1 = 2.0f * base.rgb * blend;
    float3 result2 = 1.0f - 2.0f*(1.0f-blend)*(1.0f-base.rgb);
    float3 newColor = lerp(result1,result2,L);
    float A2 = Opacity * base.a;
    float3 mixRGB = A2 * newColor.rgb;
    mixRGB += ((1.0f-A2) * base.rgb);
    return float4(mixRGB,base.a);
}