5 Replies Latest reply on Jun 27, 2009 5:54 PM by Ellis_Vener

    How does Adobe make their camera  profiles for ACR and Lightroom?

    Ellis_Vener Level 1

      I'm not interested in the proprietary algorithms , but I am curious as to the photographic mechanics and hardware tools used by  Adobe to make the various camera profiles as they differ markedly from the ones I make using the DNG Profile Editor.

       

      My methodology is to set an X-Rite 24 patch Color Checker target, light it evenly with electromic flash (with 0.1 stops from center to corners as mesured with a Sekonic L-758r Meter) and make a series of exposures bracketed in third of a stop increments around the meter reading in case the camera sensitivity differs from the meter's.

       

      I then process the raw files and convert them to the DNG format, select the best exposure and run it through the DNG Profile editor. My results differ from Adobe's generic profiles for that camera enough that that I don't thin kthe difference can be credited to the difference between a generic profile a specific camera.

      How do the different tools work in the DNG converter? Starting with the Options for "Base Tone Curve"? Is there a document a moderately color geeky person can understand that explains this?

       

      I thin kthe DNG Profile editor is a great and under usedtool. I wish more people knew about it.

       

       

      Thank you for your time and consideration.

        • 1. Re: How does Adobe make their camera  profiles for ACR and Lightroom?
          Jeff Schewe Level 5

          Ellis_Vener wrote:

           

          I'm not interested in the proprietary algorithms , but I am curious as to the photographic mechanics and hardware tools used by  Adobe to make the various camera profiles as they differ markedly from the ones I make using the DNG Profile Editor.

           

          What the "elves" are doing now I can't say...but I watched as Thomas profiled a Canon 1D MII camera. He set up the camera and shot an angled shot in a Spectra Light Jr. at D65 and Standard Illuminate A. He didn't even both to shoot the images straight on as all he needed was the color samples. The he sat back on his chair with his feet up and started the process of decoding the white balance data from the files. Pretty sure Thomas had a special purpose app he wrote to read the spectral data on a ColorChecker chart and compare the color properties and what it would take to make the captured colors match the intended colors.

           

          When Eric and the ACR team wrote the DNG Profile Editor and he and Thomas created the DNG Profile spec, the process above was considerably formalized. But I'm not sure that the capturing of the CC chart is all that special. Also pretty sure nether Eric nor Thomas need to use DNG Profile Editor pre se since that have far more advanced tools at their disposal :~)

           

          Personally, I would suggest this all falls under the "you don't really want to know" category (not unlike watching sausage making). Read the docs, do the profiles and become proficient doing that process. If you find shortcomings or have specific questions not covered by the docs, ask away...pretty sure Eric will be happy to answer.

          1 person found this helpful
          • 2. Re: How does Adobe make their camera  profiles for ACR and Lightroom?
            ssprengel Adobe Community Professional & MVP

            Someone who only eats sausage may not want to know how it's made.  Someone who creates things with food, a chef, a cook, or otherwise is thinking about a career in the food industry, might have a interest in such things.  Someone who is thinking of making sausage will want to know all the details.  Someone who is concerned with the public safety might want to know how sasauge is made.

             

            It would be nice for a sausage maker to give some hints about the process as compared to what each of us can do with the DNG Profile Editor and to the original poster's question, why are our profiles different from Adobe's?

             

            It is my experience that when I create a profile with the DNG Profile Editor, and then compute the color error for each of the 24 color patches of a CC24, using a program like Imatest, some colors are quite a bit off and some are very close, and the colors that are off, are not the same ones that are off when I compute the color error using one of the Adobe Standard or Camera Standard profiles.

             

            Is Adobe using more detailed and sophisticated color targets with hundreds of different colors, or if not, do the tools provide more feedback and allow more manual manipulation of the profile and so the differences are due to their judgement about which colors to make "right" and which ones to let have more error associated with them, that can be manipulated by hand instead of merely letting the DNG Profile Editor apparently distribute the error amongst the various colors with some sort of even-handed calculation.

             

            For example it is easy to imagine that someone tweaking a profile by hand with a live readout of the error of each of the colors plus an overall composite error, might put more emphasis on skin tones being right if they have a background in people photography, or more emphasis on bright colors being right if their experience is in textiles and the current trend in the US is bright colors--and a different emphasis when the trend is muted colors so there is cultrual bias and life-experience coloring a "standard" profile.

             

            In other words, how much of the difference between Adobe and our profiles are due to Adobe having different or better science, and how much of it is due to Adobe have different or better "artists" who decide what colors to make correct compared to others.

            • 3. Re: How does Adobe make their camera  profiles for ACR and Lightroom?
              sandy_mc Level 3

              Mostly better artists.

               

              I wrote about what's in profiles and why they are like they are a while ago; this may answer some of the questions:

               

              http://chromasoft.blogspot.com/2009/02/adobe-hue-twist.html

               

              http://chromasoft.blogspot.com/2009/02/visualizing-dng-camera-profiles-part-1.html

               

              Sandy

              • 4. Re: How does Adobe make their camera  profiles for ACR and Lightroom?
                Jeff Schewe Level 5

                ssprengel wrote:

                 

                In other words, how much of the difference between Adobe and our profiles are due to Adobe having different or better science, and how much of it is due to Adobe have different or better "artists" who decide what colors to make correct compared to others.

                 

                Both actually...because I know that the guys have access to additional tools and if need be they can write something (which was the genesis of DNG Profile Editor in the first place). The other thing you need to understand is that these guys aren't responsible for profiling just a single camera....DNG supports over 200 cameras now and continues to grow. Each one had to be profiled for Adobe Standard and many were profiled to simulate vender colors as well. While I know they obsess over this stuff, they also have to move along and get things done otherwise nothing would ever ship. So, that demands a degree of efficiency.

                 

                The other thing one should note is that the engineers also need to have this stuff end up being normalized to a large degree. As a result, sometimes they may know what the end results they want are but they current programming isn't giving them the answer they want. I know for a fact that in engineering circles at Adobe (and elsewhere) Thomas Knoll is known for his "magic numbers". Which means coming up with a piece of code that produces the results desired even though it shouldn't work...he throws in a magic number at the end of the process to get the final result he wants.

                 

                But folks, just because you think you want to know how all this stuff works doesn't give you the right to have the expectation that the engineers walk you through this stuff. Eric and Thomas are very generous with their time (when they ever have any free time) by visiting these boards. Remember these are User>User forums and they stop by just as any user might. It would be useful for people to be respectful of their willingness to participate and not expect a whole lot of info from them some of which could indeed be proprietary. Don't forget, these boards are public...anybody can see them including all the competitors to Camera Raw & Lightroom (and you better believe there's somebody from Apple that comes visit here from time to time).

                • 5. Re: How does Adobe make their camera  profiles for ACR and Lightroom?
                  Ellis_Vener Level 1

                  "It is my experience that when I create a profile with the DNG Profile Editor, and then compute the color error for each of the 24 color patches of a CC24, using a program like Imatest, some colors are quite a bit off and some are very close, and the colors that are off, are not the same ones that are off when I compute the color error using one of the Adobe Standard or Camera Standard profiles."

                   

                  Jeff's answer is very helpful in describing hopw Thomas Knoll (at least) made his profile ofa 1D MArk 3.

                   

                  thereality is that when we profile a camera we obviously have at least three if not 4 or more factors in play

                   

                  1) the specific camera body ( image capture chip + whatever tweaks are done insidethe camera accordignto the manufcturer's processing and programming)

                   

                  2 The specific target (targets do vary slightly)

                   

                  3) The lighting source used.

                   

                  4) Specific lenses could be a factor I suppose.

                   

                  5) the software and profiling process.

                   

                  And finally , your idea of what pleases your eye most  --unless of course your task is to produce an iamge where "Coca-Cola Red" or "Pepsi Blue" are rendered as close to the  CMYK or Pantone values of "Coca-Cola Red" or "Pepsi Blue" as early in the image creation process as possible.