9 Replies Latest reply on Sep 18, 2017 2:53 PM by fnordware

    Rare pixels issues


      Hello world,


      For some reason when I am doing color correction on my image it generates

      some rare squares on my image.


      I am using .EXR 32Bit Image and to target the parts i want to edit i use color keying

      and than duplicate the image and set the layer with alpha keying to alpha inverted matte.

      Is it because of that or is something else the problem ?


      Would appreciate some help.





      Original > with hue adjustments at 100% > with hue adjustments at 200%


        • 1. Re: Rare pixels issues
          Mylenium Most Valuable Participant

          I'm not sure I understand the reasoning behind your procedure. What does color keying have to do with color correction? That and of course you haven't told us anything about the effects you are using, your version of AE, your system, a screenshot of the layer stack, the source of your EXRs and their specs. A lot can go wrong when using float images and presumably it's exactly that - you are salpping on an 8bit or 16bit effect that cannot deal correctly with out of range values.



          • 2. Re: Rare pixels issues
            kenny27293 Level 1

            Oke let me explain. This is a 3D generated image. It is rendered.

            In order to do color correction on different parts individualy i rendered each part of the image

            in a solid color to target them to be able to correct only that part of the image.

            And to be able to isolate the part that need color correction I used color key to do that.


            Sorry for my bad english.


            What i use:

            macOs Sierra

            After Effect CC 2017


            On this image you can see. with the color key i target only the grey.

            and in the layer panel you can see the TH_IDs is the solid color layer.


            Screen Shot 2017-07-13 at 14.55.29.png


            and on this image you can see that i turn of the TH_IDs layer visibility

            and put the levels on the TH_AO wich is the original image.

            • 4. Re: Rare pixels issues
              Mylenium Most Valuable Participant

              Well, if you 3D-rendered it, you would simply use an Object ID pass or an RGB matte. Otherwise I maintain that you're screwing up the colors by clipping away the internal ranges of your float data. At least you would have to use the Compander effect to bring them within 0-1 ranges and then your awkward keying might even work, but to me your workflow realyl doesn't make the most sense.



              • 5. Re: Rare pixels issues
                Jose Panadero Adobe Community Professional

                Try to set your project to 32bpc. Anyway, if you are using the "Obsolete" Color Key effect, this effect did not process at 32bpc, only 16bpc and it is possible that this could cause your issue. As Mylenium says, there is no reason to do this with color key effects as you can output any Object ID from any 3D package software.

                • 6. Re: Rare pixels issues
                  kenny27293 Level 1

                  Thaks for your time. But the reason that i had to do it this way is because the renderer I am using the Object ID option is messed up. its not working properly. so i had to find a other way around.

                  its complicated lol.

                  • 7. Re: Rare pixels issues
                    Kevin-Monahan Adobe Employee

                    Hi Kenny,

                    It sounds like you resolved your issue. If not, let us know how you solved it. If so, please let us know so we can assist you further.




                    • 8. Re: Rare pixels issues
                      kenny27293 Level 1

                      Hello Kevin,


                      I did change my workflow. so that solved my prblem.



                      • 9. Re: Rare pixels issues
                        fnordware Level 3

                        I wonder if your EXR uses B44 compression, which is lossy and can produce artifacts. In general I would stay away from B44.