{"id":1708,"date":"2012-05-17T13:21:11","date_gmt":"2012-05-17T13:21:11","guid":{"rendered":"https:\/\/www.cg-blog.com\/?p=1708"},"modified":"2013-04-15T09:30:20","modified_gmt":"2013-04-15T09:30:20","slug":"add-gamma-vray","status":"publish","type":"post","link":"https:\/\/www.cg-blog.com\/index.php\/2012\/05\/17\/add-gamma-vray.htm","title":{"rendered":"Different ways to add Gamma in your renders"},"content":{"rendered":"

Every real device to take pictures adds gamma.<\/p>\n

We actually are “producers” of images and we need to correctly setup the gamma in 3ds Max, in order to imitate the behavior of real cameras.<\/p>\n

In 3ds Max the options we have to add gamma are various:<\/strong><\/p>\n

    \n
  1. Gamma in “output” \/ preferences<\/li>\n
  2. Gamma \/ color mapping<\/li>\n
  3. Don’t Affect colors \/ color mapping<\/li>\n
  4. sRGB button \/V-Ray Frame Buffer (VFB)<\/li>\n<\/ol>\n

    Every option in this list affects gamma.
    \nAs you can understand we can’t use all at the same time!
    \nWe have to choose a combination to just adds 2,2.. once!<\/span><\/strong><\/p>\n

    I’m going to show you how many combinations are possible and you’ll see just one way is the correct one.<\/p>\n

     <\/p>\n

    \n

    COMBINATION 1 : Gamma in.. OUTPUT – <\/span><\/strong>follow the green arrow<\/span>
    \n<\/strong><\/p>\n

    – Gamma in “output” \/ preferences = 2,2<\/span><\/span><\/p>\n

    – Gamma in color mapping = 1,0<\/p>\n

    – Gamma in VFB (sRGB button) = disabled<\/p>\n

    \"\"<\/a><\/p>\n

    Brief Explaination:<\/em>
    \nYou’re adding 2,2 to the final image. But in this ways will you’ll get artifacts in the shadows.
    \nThe reason is that you’re just adding a “fake” gamma – not good<\/strong><\/span><\/p>\n

     <\/p>\n

    \n

    COMBINATION\u00c2\u00a0<\/strong>2: Gamma in… sRGB button<\/strong> (follow the green arrow)<\/span>
    \n<\/strong><\/p>\n

    – Gamma in “output” \/ preferences = 1,0<\/p>\n

    – Gamma in color mapping = 1,0<\/p>\n

    – Gamma in VFB (sRGB button) = enabled<\/span><\/p>\n

    \"\"<\/a><\/p>\n

    Brief Explaination:<\/em>
    \nYou’re adding 2,2 with the sRGB button but it’s \u00c2\u00a0just a “preview” of gamma. When you save the image the gamma is not added, so you’ll see a different image out of 3ds Max! – wrong usage!<\/strong><\/span><\/p>\n

     <\/p>\n

    \n

    COMBINATION 3: Gamma in.. Color Mapping (perfect) – <\/strong>follow the green arrow<\/span>
    \n<\/strong><\/p>\n

    – Gamma in “output” \/ preferences = 1,0<\/p>\n

    – Gamma in color mapping = 2,2<\/span><\/span><\/p>\n

    – Gamma in VFB (sRGB button) = disabled<\/p>\n

    \"\"<\/a><\/p>\n

    Brief Explaination:<\/em>
    \nYou’re adding gamma 2,2 during the computation: that’s fine! Simple and effective.
    \n<\/span><\/strong><\/p>\n

     <\/p>\n

    \n

    COMBINATION\u00c2\u00a0<\/strong>4: Gamma…\u00c2\u00a0 included but not visible <\/strong>(for compositing) – follow the green arrow<\/span><\/p>\n

    – Gamma in “output” \/ preferences = 1,0<\/p>\n

    – Gamma in color mapping = 2,2<\/span> \/ don’t affect colors = enabled<\/span><\/p>\n

    – Gamma in VFB (sRGB button) = enabled (for preview)<\/span><\/p>\n

    \"\"<\/a><\/p>\n

    Brief Explaination:<\/em>
    \nYou’re adding gamma 2,2 during the computation
    \n“Don’t affect colors” hide gamma but avoid artifacts
    \nUse sRGB button just to have a preview<\/p>\n

    This way is perfect if you want to save in EXR or you want to add gamma in compositing with more layers. In these case sRGB button is really useful to preview how the image will looks after added gamma in compositing.<\/strong><\/p>\n

     <\/p>\n

    \n

    CONCLUDING<\/strong><\/h2>\n

    <\/strong>Resuming all combinations:<\/p>\n