17 Replies Latest reply on Jun 18, 2012 11:48 PM by acresofgreen

    How to remove the pink / purple lines surrounding objects in photograph

    wvd2012

      I've been getting pink or purgle lines bordering certain objects in my photographs. You can see them on the RAW images. When I merge them using HDR you can see how prominent the lines become. I'm not sure if the problem occurs in my camera (Canon T2i) or lens when I take the shot.

      I've tried using Color Range and the Magic Wand Tool but it is a tedious process.

      Are there any recommendations or tools that might help me to remove these lines quick and easy?

       

      Thank you in advance

      wvd2010

       

      Pink lines bordering objects in photograph.jpg

        • 1. Re: How to remove the pink / purple lines surrounding objects in photograph
          Curt Y Level 7

          It appears the pink line is a chromatic aberation at the juncture of highlight and shadow.  I would suggest you find the root cause as like you say eliminating after the fact is a tedious job.

           

          Do you have another lens you can try?  It could also be the digital sensor in the camera.  Try different zoom settings on same picture.  If new camera/lens it may be defective and you can exchange. 

           

          Looks like a good photo canidate is a beam in shadow against a bright background, but not too washed out.  Best shot to show problem is lower right one.

           

          Try a web search for this problem.

           

          Hope this helps.

          • 2. Re: How to remove the pink / purple lines surrounding objects in photograph
            b2martin_a Level 2

            This appears to be Chromatic Abberations, which is a characteristic of the lens.  Which RAW converter are you using?  Adobe has a function in the latest versions of ACR 6.7 and ACR 7 that automatically removes chromatic abberations, it's located in the lens correction tab and is a box you check (Remove Chromatic Abberations).  In ACR 6.6 and earlier you corrected it with sliders in the lens correction tab. 

            • 3. Re: How to remove the pink / purple lines surrounding objects in photograph
              Noel Carboni Level 8

              Not completely certain in your case, but it's often a sensitivity to IR (and sometimes UV) that causes that.  A good clue is that it happens on contrasty edges next to sunlit subject material.

               

              As b2martin_a mentions, the very latest Camera Raw converter has some color fringing enhancements to help with it as well, though the current release (7.1) has some glitches in it.

               

              On another note...  I have tried and tried to get good results out of Merge to HDR and I simply keep coming back to the conclusion that I can simply get better looking results out of extreme adjustments to a single exposure - e.g., your RAW 3 image - ESPECIALLY with the new Camera Raw PV2012 controls.  Do try Photoshop CS6 when you get a chance.  You may find a solution to all your issues, and one that yields results more quickly as well.

               

              -Noel

              • 4. Re: How to remove the pink / purple lines surrounding objects in photograph
                Trevor.Dennis Adobe Community Professional

                I always use Photomatix for HDR, which has a 'reduce chromatic aberations' feature, but even Photomatix tend to work best when the bracketed set are first converted from RAW to 16 bit TIFFs.  That way you get the best out of the RAW files by using ACR, which HDRsoft (the company who makes Photomatix) freely admits does a better job of converting RAW files than does their own software.  As Noel says, there are good tools for fixing CAs in ACR.

                • 6. Re: How to remove the pink / purple lines surrounding objects in photograph
                  Frank Heller Level 2

                  Noel Carboni wrote:

                   

                  Not completely certain in your case, but it's often a sensitivity to IR (and sometimes UV) that causes that.  A good clue is that it happens on contrasty edges next to sunlit subject material.

                  Um....not really.

                   

                  http://en.wikipedia.org/wiki/Chromatic_aberration

                  • 7. Re: How to remove the pink / purple lines surrounding objects in photograph
                    Noel Carboni Level 8

                    Um...  Really.

                     

                    Thanks, but I'm kind of past the basic definition of CA.  I have had cameras that were more and less sensitive to IR and thus the red fringing next to hot bright areas.  I do know what I'm talking about.

                     

                    Of course not all color-fringing is IR sensitivity but what is being shown in the images above is just that, I believe.  Here's another good example of it.

                     

                    RedFringing.jpg

                     

                    -Noel

                    • 8. Re: How to remove the pink / purple lines surrounding objects in photograph
                      Frank Heller Level 2

                      Thanks, but I'm kind of past the basic definition of CA.

                      Apparently so.

                       

                      Whether you empirically wish to believe that frequencies outside the visible range are manifesting themselves as visible light in the form of fringing is fine by me, but anyone reading the article (and its reference articles)  will notice that nowhere is light beyond the visible spectrum (UV and IR) specified or mentioned as a potential contributing factor in the manifestation of chromatic aberration.

                      • 9. Re: How to remove the pink / purple lines surrounding objects in photograph
                        Noel Carboni Level 8

                        Frank, why would you and others reading here choose to believe folks writing Wiki articles are more knowledgeable than folks with photography experience answering specific questions here?  I applaud your skepticism, but you might want to learn more before actively trying to discredit my input.

                         

                        I invite you to read up on why camera makers put IR-blocking filters over camera imagers - some so aggressive that they actually block deep red light as well (astrophotographers care about this).  You might notice that some cameras can be used for near IR photography with filters and some not so much - ask yourself why that might be.

                         

                        -Noel

                        • 10. Re: How to remove the pink / purple lines surrounding objects in photograph
                          Frank Heller Level 2

                          You know, Neil, nothing makes me laugh as much as someone casting dispersion on the credibility of a well laid out technical Wiki article, as a form of rebuttal.

                           

                          Perhaps you could enlighten us all with a reasonable scientific explanation as to how or why wavelengths, beyond the visible spectrum, show up as visible fringing?

                           

                          And while you're at it, could you perhaps explain how the authors of the Wiki article could be so obtuse as to completely disregard or ignore the subject?

                           

                          Seriously, why would they even bother to put as much detailed work into the discussion of chromatic aberration and not include the concept of IR and UV leaking into film or a CCD as a potential source of fringing in photography?

                           

                          I mean tell me….if it is a scientifically known cause….why on earth would they leave it out of the article? What would they have to gain by doing so?

                          • 12. Re: How to remove the pink / purple lines surrounding objects in photograph
                            wvd2012 Level 1

                            Thank you very much to all. It is extremely useful information.

                            Noel, your info was especially useful and helpful.

                            Thanks so much!

                            • 13. Re: How to remove the pink / purple lines surrounding objects in photograph
                              Curt Y Level 7

                              Frank Heller wrote:

                               

                               

                              Whether you empirically wish to believe that frequencies outside the visible range are manifesting themselves as visible light in the form of fringing is fine by me, but anyone reading the article (and its reference articles)  will notice that nowhere is light beyond the visible spectrum (UV and IR) specified or mentioned as a potential contributing factor in the manifestation of chromatic aberration.

                              I am not an expert in this field but know that with most topics, the more one digs into it, the more interelated factors are exposed.  If one includes all the factors in chromatic aberration it would be mind numbing and most would not be able to follow.  So would assume the Wiki author wanted to explain it the best they could without loosing everyone.  Would need a NIkon optics expert for the real story.

                               

                              Each color, visable or not, is a wave.  As such they can combine for form harmonics.  So two or more very short wavelength colors, IR for instance, can combine and form a harmonic that is of a lower frequency.  But this is much easier to see in a wave tank of water than with light.  And with a huge array of frequencies it is difficult to predict.  Just another opinion.

                              • 14. Re: How to remove the pink / purple lines surrounding objects in photograph
                                Noel Carboni Level 8

                                It's even simpler than that:  Camera sensors don't have the same limitations as eyes regarding what's "visible".  Most sensors are VERY sensitive to near IR wavelengths.

                                 

                                -Noel

                                • 15. Re: How to remove the pink / purple lines surrounding objects in photograph
                                  Paulo Skylar Level 4

                                  This thread started with a very clear concise query, but got somewhat off track due in part to some technically soft comments. The relevant technical issues can easily be found in many places so there really should not be much disagreement.

                                   

                                  First, some practical input: Does the T2i camera see & record "infrared"? Absolutely, as could be inferred from the physics of the components involved. As a little show-and-tell, I happen to have one of those cameras around here so I pointed it at a darkened monitor/room with one hand and pointed and pressed a TV remote control at the screen with the other hand (shaky with the long exposure time). Here is a crop from that image clearly showing the "infrared" light from the remote.

                                  IR.jpg

                                  Second,

                                   

                                   

                                  Frank Heller wrote:

                                   

                                  .......

                                   

                                  Perhaps you could enlighten us all with a reasonable scientific explanation as to how or why wavelengths, beyond the visible spectrum, show up as visible fringing?

                                   

                                  The response spectra of real life physical devices do not cut off abruptly even though we often want them to. They have "tails" at the boundaries or have soft boundaries so there is no absolute definition of where "visible" light starts and stops. You may frequently see the low frequency end of the visible spectrum listed as 700 nm. Digital cameras used CCD sensors and the fundamental process involved in their operation is photons of light being absorbed in Silicon and producing electron-hole pairs. That process is incredibly well understood and documented and guess where the wavelength PEAK of that process is -- about 700 nm.  Note that does not mean it ends there, but its maximum response occurs there and goes out to about 1000nm. So camera manufacturers have to design and filter for that with imperfect results. When these wavelengths at and around 700 nm are absorbed they are "shown" by the camera as red.

                                   

                                  This situation is made worse by the fact that the optic elements do not perform well at & beyond 700 nm, that is, in the infrared.  They are optimized for visible operation. This means that lateral chromatic aberration (CA) gets worse in that frequency region. So if a high key natural light scene occurs then a) you may see CA from the camera optics/processing of "visible" light and b) you may also have a component from IR in the scene. It is conceivable that the IR component could dominate- the truth is in the details.

                                   

                                  Paulo

                                  • 16. Re: How to remove the pink / purple lines surrounding objects in photograph
                                    Noel Carboni Level 8

                                    Thank you for elucidating, Paulo. 

                                     

                                    I first encountered the phenomenon quite a few years ago when I was comparing images taken of an automobile with two different Canon digital cameras a few minutes apart from the same vantage point using the same lens.  One camera produced distinct red fringes along the edges of some hot, shiny chrome and the other did not.  I vaguely remember the cameras were EOS-D60 and EOS-10D, but I wouldn't swear to it.  Further investigation revealed that one camera had been given a much more aggressive IR-cutoff filter than the other, which was later confirmed by enthusiasts who pointed out that one camera was more usable for IR photography (with suitable bandpass filter over the lens) than the other.

                                     

                                    -Noel

                                    • 17. Re: How to remove the pink / purple lines surrounding objects in photograph
                                      acresofgreen Level 4

                                      Frank Heller wrote:

                                       

                                      You know, Neil, nothing makes me laugh as much as someone casting dispersion on the credibility of a well laid out technical Wiki article, as a form of rebuttal.

                                       

                                      Not even the folks at Wikipedia assume that anything written there is 100% true or complete.  Why do you?