El 14/04/16 a las 21:12, Stephen escribió:
> An interesting technique. It changes the mood quite a bit.

   Well, I forgot to say that apart from the "blending" of the old paper
image, I applied also some random changes to the color curves to
simulate the "vintage" coloring (I was too lazy to investigate proper
curves for the different "vintage" effects, so I resorted to our old
friend "rand"):

    // random vintage effect
    #declare r_v=seed(1709);
    #declare exp_r=rand(r_v)*2;
    #declare exp_g=rand(r_v)*2;
    #declare exp_b=rand(r_v)*2;
    #declare sat=1-.75+rand(r_v)*.25;
    #declare f_old_paper=
    function{
      pigment{
        image_map{
          jpeg "jvp_old_photo_back_1"
          interpolate 2
        }
        scale <1,-1,1>
        #if(image_height>image_width)
          rotate 90*z
        #end
      }
    }
    tonemapping{
      parameters{red,green,blue,gray,x,y}
      function(r,g,b,gr,x,y) 
{max(pow(r,exp_r),f_old_paper(x,y,0).red)*(1-sat)+gr*sat}
      function(r,g,b,gr,x,y) 
{max(pow(g,exp_g),f_old_paper(x,y,0).green)*(1-sat)+gr*sat}
      function(r,g,b,gr,x,y) 
{max(pow(b,exp_b),f_old_paper(x,y,0).blue)*(1-sat)+gr*sat}
    }

    Just change the random seed until you find a nice coloring...

--
jaime

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