LUTs

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  • #215179
    jomosadler
    Participant

      Hello Mr. Deakins,

      Do you usually shoot in REC709 on set and color later or do you usually have a custom LUT beforehand to look at for each project. If you use a custom LUT, would you have multiple say for interior/exterior? And how do you go about testing a custom LUT beforehand in pre-production?

      Thank you

    Viewing 15 replies - 1 through 15 (of 17 total)
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    • #215185
      halfgrain
      Participant

        Hi,

        I hope it’s OK to answer part of your question, since this is something he has talked about in numerous interviews and the podcast. Usually, a LUT is developed for the particular movie beforehand and Roger uses this LUT for monitoring during the whole shoot of the whole movie. I’m not sure if he ever had multiple LUTs for different scenarios, though my guess would be most likely not.

        As far as testing beforehand, I would think once you developed a color palette with the production designer and maybe already have set pieces and wardrobe to test it on, you can just develop the LUT to your liking and tweak it until you’re happy.

        #215186
        Stip
        Participant

          He uses the same LUT on every movie.

          Roger on this forum:

          The LUT we use was created at E-Film, now Company 3.  It is not hard to do. Just shoot some tests and take them to the DI suite.

          I would be very surprised if the LUT I use is very different from any other. The only adjustment in it is to the contrast curve and the amount of color saturation. That is standard for any LUT that translates the RAW data.

          Show LUTs in general aren’t too funky because they must work in all situations and are tested in all situations before actual shooting.

           

          #215187
          dmullenasc
          Participant

            You need some sort of LUT to convert a raw/log signal for display on a monitor, whether Rec.709 or P3 — most personal LUTs are close to the standard Rec.709 LUT, just tweaked either for personal taste or for a specific look.

            #215188
            LucaM
            Participant

              He uses the same LUT on every movie. Roger on this forum:

              The LUT we use was created at E-Film, now Company 3. It is not hard to do. Just shoot some tests and take them to the DI suite. I would be very surprised if the LUT I use is very different from any other. The only adjustment in it is to the contrast curve and the amount of color saturation. That is standard for any LUT that translates the RAW data.

              Show LUTs in general aren’t too funky because they must work in all situations and are tested in all situations before actual shooting.

              In other words It’s a LUT for the initial color correction, not for the grading, Is It correct?

               

              #215189
              Ryan Jackson
              Participant

                There’s a great episode of the podcast with Joachim Zell from Company 3 where they discuss LUTs. All it is a file that tells the grading software to change one set of values to another. Hue, Saturation, and Contrast usually being the main ones targeted. Most manufacturers will release a LUT on their website for their cameras to correct the Log image to an image that looks “correct” on the monitor you are viewing on. For example Arri Log-C to Rec.709 LUT converts the values of Log-C to values that look correct on a Rec.709 monitor.

                On set LUTs are used to correct the image so that anyone viewing the feed on a monitor will see a corrected version of what is being captured by the camera.

                In a grade, they can be used for either a basic correction or for a specific look. It all depends on the DP and colorist’s way of working.

                They are just a tool.

                #215190
                Stip
                Participant

                  In other words It’s a LUT for the initial color correction, not for the grading, Is It correct?

                   

                  No, Roger said he would sit with the colorist and go through every shot to tweak exposure (besides color correction to match shots) but no additional grading.

                  If you watch Roger’s films shot on Alexa, the differences between them come from lighting, set design, costume ect but ‘grading’ is the same for all of them. The only variables used are color temperature (and I suspect tint).

                  #215192
                  LucaM
                  Participant

                    In other words It’s a LUT for the initial color correction, not for the grading, Is It correct?

                    No, Roger said he would sit with the colorist and go through every shot to tweak exposure (besides color correction to match shots) but no additional grading. If you watch Roger’s films shot on Alexa, the differences between them come from lighting, set design, costume ect but ‘grading’ is the same for all of them. The only variables used are color temperature (and I suspect tint).

                    I know his goal is  to obtain the desired effect directly in camera, which (together with his naturalistic and motivated approach) is a bit of a mind opening way to look at things, since we live in an era in which a lot of what we see and how we see it (not only in movies) it’s created by a pc. The best part is that, like all the masters, he makes it look quite easy!

                    #215195
                    dmullenasc
                    Participant

                      In other words It’s a LUT for the initial color correction, not for the grading, Is It correct?

                      Isn’t “grading”, “timing”, and “color-correction” all the same term? The only differentiation today in digital is whether it is for dailies or for the final master. Sometimes VFX elements are pre-graded, or plates for process work.

                      Camera LUTs are mainly for on set displays and for dailies. Whether they get used as a starting point for the final color-correction just depends on how the colorist and cinematographer like to work. Some might start from scratch from the raw files but then throw on the camera LUT now & then to see how close or far they are.

                      #215200
                      K.Wasley
                      Participant

                        The work and skill that goes into building a LUT like Rogers seems to be extremely underestimated.

                         

                        Roger’s LUT won’t look anything like arri’s rec709 LUT because Rogers LUT is built from a print film data set and also incorporates an Alexa to film negative transform, as per Joachim Zell’s description. It took weeks to create the LUT.

                         

                        If you went into a DI suite and applied arri’s standard 709 LUT then tweaked with contrast and saturation or other standard colour corrector tools you wouldn’t get close to Roger’s in terms of the colour behaviour. For example highly saturated colours becoming dark and rich with a film like subtractive saturation. Take a look at the greens you get out of arri 709 – bright and garish vs the greens you’ll see in Rogers work that have far more of the print film yellow character and are less saturated and bright. Creating a LUT like Roger’s isn’t easy to do in the slightest, for a start you have to have a large film data set, a very complex undertaking. Then you have to develop custom tools for clean colour manipulation, tools which are not available in a standard color corrector.

                         

                        Roger’s LUT isn’t like any other, simply because LUT’s vary wildly, are built in thousands of different ways, based on very different data sets, and built by skilled and non skilled people. Each LUT has its own personality and characteristics. Some are simple, but the complex and smooth film based LUTS like Rogers, built on rich data sets are rarely available to the public and for good reason. These types of LUTS are usually built by colour scientists at post facilities or bespoke for a project – for example Kodak colour scientist Mitch Bogdanowicz who built the LUT for Joker – which emulated an out of production film stock.

                         

                        When Roger tweaked his LUT in a DI suite, as Joachim Zell who built the LUT describes – a huge amount of work to build the LUT would already have taken place. The tweaking of saturation and contrast at this point would represent small changes to an already complex model that had been previously built.

                         

                        Whilst a LUT certainly is just a part of a look, it’s certainly still a significant part because it essentially represents a digital ‘film stock’, building in contrast, colour crossover (eg blue blacks warm highlights), hue v hue, saturation and complex non linear colour characteristics (eg bright garish colours becoming darker). These characteristics can have a huge impact on an image, not to mention on how you light. Rogers contrast curve will have quite a bit more contrast than Arri’s 709 K1S1 LUT for example because it is based on a print film data set. One result of this is that when lighting you will inevitably put more light into your shadows than you would if monitoring through Arri’s LUT. Steve Yedlin talks about this quite a bit also. Steve has his own model built using custom tools from a 5219 printed to 2383 data set.

                        #215201
                        Stip
                        Participant

                          When Roger tweaked his LUT in a DI suite, as Joachim Zell who built the LUT describes – a huge amount of work to build the LUT would already have taken place. The tweaking of saturation and contrast at this point would represent small changes to an already complex model that had been previously built.

                          If I remember correctly, ‘True Grit’ was a guideline from Roger for the development of the LUT. I hope he can correct me if there was more to it.

                          #215204
                          K.Wasley
                          Participant

                            As JZ described. When True Grit shifted from film projection to digital display JZ and Arri profiled the 2383 print. This was the basis for the LUT when moving to Alexa, with an additional step of converting the Alexa output to better represent a negative before going through the profiled 2383 print.

                            I would imagine that when Roger tweaked the LUT  it was contrast / saturation adjustments being made underneath the print film profile JZ had previously developed ie the large majority of the colour and contrast reproduction of the LUT was already set. This final adjustment would then be baked into the final LUT which goes into production (loaded into monitors or potentially into the camera itself  if the camera is capable of 33x 3D LUTS, which is the case for cameras from Alexa SXT / Amira onwards).

                            #215214
                            Stip
                            Participant

                              Thanks for the background info.

                              Fwiw, I use a scene referred 2383 Print Film LUT (free from Lutify) in color managed Davinci Resolve with good success. Contrast might be too high for cameras with less dynamic range than Alexa though.

                              #215216
                              K.Wasley
                              Participant

                                Thanks for the background info. Fwiw, I use a scene referred 2383 Print Film LUT (free from Lutify) in color managed Davinci Resolve with good success. Contrast might be too high for cameras with less dynamic range than Alexa though.

                                I would note that there is a big difference between applying a print LUT in post to shooting through a print LUT on set as Roger and many other cinematographers do. You will light differently and also will be able to produce an image that is much closer to the intention if the show LUT is set before shooting. I don’t think the contrast of the LUT has too much bearing on what camera is used. If anything, using a more contrasty LUT on set will give you MORE information in post becuase you’ll put more fill light into shadows and less into highlights. Shooting through a flat LUT will render the opposite ie less information in the shadows. There are so many benefits to establishing a LUT before shooting and then shooting through it, not least that more of the cinematographers intention will be in the dailies / offline edit that the director etc get used to.

                                #215219
                                dmullenasc
                                Participant

                                  The primary purpose of the 2383 print emulation LUT isn’t to create a film look, it’s to work within a color space/gamut that works for both a DCP and a film-out so the movie would look the same in both versions. It’s less of an issue today with so few film-outs being done.

                                  #215221
                                  jomosadler
                                  Participant

                                    Wow. Thank all of y’all for your feedback. I will do my best to create the best possible LUT for my project and definitely check out the podcast episode over LUTs.

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