10 Replies Latest reply on Nov 22, 2012 2:40 AM by Pierre Devereux

    Delving into the murky seas of Colour Correction

    Pierre Devereux Level 2



      Recently we went on location and took a series of test footage shots. These shots were from various locations, as well as various times of day. We are aware of the "Before 10am and After 4pm" shooting rule, but, being the curious little chaps we are, we decided to try a range of shots and see what we can achieve in post with colour correction (sorry, I can bring myself to leave out the "u").


      I have two main questions that I hope can be answered by someone with more colour correction skills than I have (and I am guessing that includes most of the panel here! )


      1) Our project is aimed at the HDTV market, and will hopefully be aired in the UK. Now that I am using colour correction software (SA Color Finesse 3 for now) I notice that there are "Limiters" that can be used to prevent breaching certain broadcast rules. The only choices I have in SACF3 are for NTSC, PAL or ATSC. Does HDTV fall under any of those? Speaking to some of the others, we are under the impression that HD is in a league of its own. I have a specific shot that I am testing with, and when the limiters are enabled, there is very little I can do without breaching some limit or another. There is a terrible blue tint to the shot, and when I adjust the RGB settings for Master, and then Blue channel, the sky breaches the limits almost immediately.


      2) The second question is specifically for the shot mentioned above - I will add a screenshot below. I am not sure what was done on location to produce such a terrible blue tint, but it is in fact a brilliant shot for me to test on. I guess that a perfect shot would have been pretty useless as tool to hone my skills on! If I use no limiters on SACF3, I can get the brightness up quite nicely and remove a great deal of the tint, returning the shot to a very pleasant one - on my PC that is - How would I go about doing this, assuming the answer to question 1 is that I need those limiters enabled.


      Well, I hope this makes sense, as it sounded good in my head, but Devereux junior has picked up his second cold at 6months, so the little sleep I was getting....has just been halved again!


      Thanks guys.


      Blue Tint.jpg



        • 1. Re: Delving into the murky seas of Colour Correction
          cfg_2451 Level 2

          First thing to do is get a copy of Van Hurkman's book Color Correction Handbook. Excellent book, highly recommended.


          The UK is, I think, a PAL country, so you'll want the PAL broadcast rules.


          I almost always start color correction by looking at a waveform monitor and setting my black and white points, then my contrast. Note that you'll meet very limited success trying to set levels and contrast by eye with a computer monitor. A computer monitor is not the same as a TV, or a production monitor (a TV on steroids with lots of control). What I'm saying is that just because you got your image to look good on your computer monitor doesn't mean it's going to look good on a TV.


          In any case, set your black and white points and your contrast, then work that very blue color cast. Pulling the picture back toward orange (the negative of blue) shouldn't push your image beyond broadcast limits in any case. It should, in fact, pull it back from exceeding limts on the blue axis.


          The Van Hurkman book will explain it all, and is immenently readable too. It'll answer questions you don't know enough to ask.

          • 2. Re: Delving into the murky seas of Colour Correction
            Dave LaRonde Level 7

            Have you seen Andrew Devis' excellent set of tutorials on using Color Finesse for color correction on the Creative COW?  They're worth a look.

            • 3. Re: Delving into the murky seas of Colour Correction
              Mylenium Most Valuable Participant

              Just a few random bits and pieces:


              • HD uses either the full RGB ranges or is limited between 16-235. You know, Rec 709 and that.
              • The blue cast is from a wrong color temperature setting on the camera. Whether or not it can be recovered would depend on seeing some scope readouts.


              And of course CC only makes sense if your monitor is reasonably calibrated and has good gamut. As a minor, it should have a decent setting for factory default sRGB at 6500k color temperature and it doesn't hurt to have a good wide gamut screen...



              • 4. Re: Delving into the murky seas of Colour Correction
                Pierre Devereux Level 2

                Hi Guys,




                Thank you for the link - I will look into the book first thing in the morning. I have already built up a rather nice After Effects, Filming, Lighting and Green Screening library, I look forward to adding Colour Correction to it. I did assume that I would have to adhere to the PAL standards, but hoped that HD would do away with all the worry - Oh well....




                Thanks for the tip, I am a big fan of Andrew Devis, and have collected his entire After Effects basics tutorials so far - He has a great way of explaining the tools he uses, and I enjoy his clips. I will check out his Color Finesse tutorials tomorrow while I wait for the book.




                Thanks for the info. I had my previous iMac colour corrected to work under the specific lights we had in the old office, now I am in a new office, and I have a new PC. I hope that the monitor I have for the PC will be ok. We bought a nice large LED HD TV a while back, and the guy who came to do our colour correction explained that it was a bit of a waste, as it has so many "Auto" settings with no real explanation of what they do. As a result, he explained we would never know exactly what was going on, or if the TV was trying its own correction in the background - making what we see, completely different to other screens. I dont think we can get a production monitor at the moment, but Ill get them in to check what they can do with my PC screen. I still use an iMac, but it has the latest OS on, and according to the colour chaps, the software and calibration unit they use is incompatible with it. So unless I want to buy my own calibration units, Ill have to stick to the PC.


                Once again, thanks to all so far. thes past few months have been an incredible journey, and withtout the input from the people on this forum, it would have been over ages ago!


                (I am going to have to make a special mention of each of you in the shows credits!)



                • 5. Re: Delving into the murky seas of Colour Correction
                  Pierre Devereux Level 2

                  Hi Dave,


                  I am looking up the links on Creative Cow - are ou refering to his tutorials from 2 years back?




                  I have book marked them and will continue in the morning, but if I am missing some, would you mind a lionk or two?


                  Thank you



                  • 7. Re: Delving into the murky seas of Colour Correction
                    Rick Gerard Adobe Community Professional & MVP

                    Some of the best explanations of color correction I've ever seen are in the Red Giant tutorials for Colorista by Stu Maschwitz. Even if you never use Colorista, take a look and think about what you're trying to do. Except for the selective color keying inside Colorista, you can basically accomplish all the color correction you may ever need with AE's built in tools. Dedicated tools, and there are a bunch of good ones included with CS6 Suites, make it much faster and easier once you understand what you're looking for.

                    • 8. Re: Delving into the murky seas of Colour Correction
                      Pierre Devereux Level 2

                      Hi Rick,


                      Thanks for the input. I am actually getting pretty flustered here, as "colour" is such a big part of any project, and I am concerned that I dont know nearly enough - my biggest consern is not really the look, as the nature of our project allows us to use whatever look we see fit per shot, but what concerns me are all the rules and regulations around broadcast TV. I have managed, over the course of the past few months, to come to grips with "safe zones" for screens, Data rate minimums and quality references (HD, SD, 1080, 720 etc) - and yet every time I seem to solve one concern - 100 more show up.


                      Not for a minute did I ever thinmk this line of work would be easy, but since there are only three of us working on the project, we all have to do something of everything, and i guess I am just facing a bit of a mental brick wall at the moment.


                      Anyway, enough about my issues....


                      Thanks to all, Ill be getting the books and checking out al the online help mentioned in the post - lets see if I can make a brighter, less blue clip without breaching any of the PAL limits!



                      • 10. Re: Delving into the murky seas of Colour Correction
                        Pierre Devereux Level 2



                        Well, the book arrived today - now for some light reading!


                        Thanks for the tip - Ill comment back in a few days once I have gone through it.,