Scene Linear Workflow / ACES achieves an ideal workflow by viewing images that accurately record the light present in a scene through RRT (Reference Rendering Transform), which was developed to define color reproduction that is faithful to human perception. The RRT is a reference rendering transform (RRT) developed by AMP. This RRT has been developed as a component of AMPAS’ ACES (Academy Color Encoding System) since 2005. The RRT incorporates many of the characteristics of motion picture film and the basic research technologies that Fujifilm has cultivated over the years. The following is a look at the history of RRT, with Fujifilm at the center.
The AMPAS IIF project (The Image Interchange Framework, now renamed ACES), which began with SIGGRAPH in 2004, requested cooperation from color science experts and post-production companies at an early stage in order to promote the project. The project was initiated by the AMPAS IIF project (now renamed ACES), which requested cooperation from color science experts and post-production companies. The project gathered distinguished members such as Ed Giorgianni, a former color scientist at KODAK, and Jim Houston of SONY Pictures Entertainment. From 2005 to 2008, KODAK engineers played a central role in building the ACES technology. technology from 2005 to 2008, KODAK’s engineers identified a challenge: how to create a faithful recording of the real world. The technical challenge was to render scene linear data (ACES), which faithfully records the real world, on a display that mimics the color reproduction that humans can perceive. Initially, KODAK led the way with a theoretical computational approach that applied complex human visual algorithms to the rendering equation. However, the RRT39 rendering results produced by this approach were far from the colors and desirability remembered by actual viewers, and it was extremely difficult to derive a reference rendering formula. At that time, due to a personnel change at Fujifilm, Mitsuhiro Uchida, who had been engaged in film development, and Yasuharu Iwashiro, who specialized in color management, decided to join the Motion Picture Film Business Contribution Group, and immediately attended a regular ACES meeting in February 2009. Based on the results of this meeting, Fujifilm decided to engage in full-scale technical cooperation centering on RRT, which had been the biggest obstacle to overcome. Coincidentally, KODAK, which was in deep financial difficulties at the time, found it difficult to participate in the ACES regular meeting and disappeared after the February meeting, replaced by Fujifilm. For Fujifilm, this was a major turning point in its full-fledged entry into the research and development of next-generation standards, with the goal of making a technological contribution to the global motion picture industry.
AMPAS IIF Commitee Member
At first, the move Uchida and his team took to develop RRT was the exact opposite of what KODAK did. The move was to use a computer simulation of the characteristics of motion picture film, which has also been developed over many years to be perceived favorably by humans, to deal with the complex problem of color reproduction as perceived by humans. This is a qualitative and rational approach to a complex problem involving the characteristics of filming and monitor devices and human visual characteristics, based on computer simulations of analog film color reproduction research that has been conducted since 1935. As a candidate for RRT, Uchida developed a simulation of Fujifilm’s representative negative and positive films and provided AMPAS with a rendering conversion with digital aptitude in January 2010. Based on this rendering, RRTdc2 (Design Candidate) was prototyped in July 2010 and versioned as RRTdc2.2 in 2011 after several revisions. This RRT was highly favored for its film-like color reproduction, and was tested at production houses with close ties to AMPAS. However, it also had some shortcomings. The non-linear characteristics unique to film caused hue rotation in highly saturated colors, and the difference in dynamic range between film and ACES resulted in artifacts in the high-luminance and high-saturation range. To compensate for these shortcomings, Uchida and Iwashiro radically revised the RRT calculation method and created an extremely simple RRT algorithm that uses RRTdc2.2 as the target data for tuning. As a result, a new version of RRT was created that compensates for shortcomings and achieves desirable color reproduction by controlling color reproduction by hue, with weight given to skin tones, natural greens, and blue skies. This version was named RRTut3.3 ( Uchida Tune ) because of Uchida’s contribution. This RRT prototype was incorporated into software such as OpenColorIO1 and used in many actual productions2. However, RRTut3.3 still lacked some desirable color reproduction and the difficulty of RRT inversion remained an issue. Based on RRTut3.3, modifications were made to incorporate an algorithm for inverse transformation and hue preservation that overcomes these issues, and as of February 2014, RRTv0.7.1 has been released. The ACES Day at the Academy, held on June 4, 2014 at the Linwood Dunn Theater, featured a lively discussion on ACES version 1.0, which is scheduled for release in the fall of 2014.
Film emulation process by FUJIFILM
By the way, in addition to RRT, other technologies such as ADX ( Academy Density Exchange Encoding ), IDT ( Input Device Transform ), and ODT ( Output Device Transform ) exist in ACES. In parallel with its contribution to RRT, Fujifilm provided AMPAS in June 2009 with the parallels necessary to determine the color balance of the ADX color space, which digitally standardizes the density of negative films. In addition, the parameters of Universal Unbuild, which is a conversion formula from ADX color space to ACES color space, were calculated through Fujifilm-led arbitrary spectroscopy experiments. For IDT, which is used to remove the device characteristics of digital cameras and convert them to ACES space, Fujifilm and SONY collaborated to calculate IDT and conducted comparison experiments on ACES. In addition, for ODT for color management of output monitor devices, we presented the design policy and concrete design examples, and was officially certified as ODTdc2 (Design Candidate) in July 2010.
FUJIFILM’s technical contribution to the development of the ACES standard
After researching and developing such ACES workflows, Fujifilm launched a hardware development project (development code name: CCBOX) in the fall of 2011 to seamlessly realize ACES workflows. As of January 2011, CCBOX was still in the research and development stage, but Mr. Hirano, who was stationed in Los Angeles, asked Mr. Uchida to introduce CCBOX at the NAB Show in April of the same year. The Los Angeles representative, Mr. Hirano, asked Mr. Uchida if he would be interested in demonstrating CCBOX at the NAB Show in the U.S. in April of the same year to see how users would react to the product. In the final push, less than a month before the NAB Show in April, the Great East Japan Earthquake hit Japan. The Great East Japan Earthquake hit Japan. The Miyadai R&D Center (Kanagawa Prefecture), which was the development headquarters, was also hit by the earthquake, which caused great confusion in terms of transportation networks and power supply. In the midst of the turmoil, we worked on development, even giving up weekends in order to make it in time for NAB in April. With the prototypes finally completed, Mr. Uchida and Mr. Iwashiro, who were in charge of development, flew to the U.S. to conduct a real-time color-matching demonstration of ALEXA and F35 on ACES. The world’s first ACES-compatible hardware was well received, and in August 2011, after NAB, we moved from the R&D phase to the product development phase, and in April 2012, we released the product under the name “IS-1003 ” in the United States. In Japan, based on the actual use of the IS-100 in the movie “Brain Man,” a seminar4 was held at NAC Image Technology in July 2012 to introduce the ACES workflow, and the IS-100 was launched in Japan in October 2012.
Fujifilm has been involved in the motion picture industry since its establishment in 1934 as a film sales company. Needless to say, the company has grown around film technology. In addition to film, Fujifilm has been providing high-performance lenses to the film and TV industry. Surprisingly, it was the research and development of ACES and RRT that led to the company’s first foray into digital device development for the film industry in 2012. It is a mere coincidence that Fujifilm’s film production ended at the same time as the establishment of the ACES standard*5 for SMPTE in 2012, which was the fruit of Fujifilm’s efforts in RRT, which was based on computer simulation of film-look that had been studied for many years. RRT, the most emotional of the rational ACES standards, was shaped by the strong commitment to the film look of the members involved in its development. As such, RRT must surely inherit the good assets of film.
2）For VFX video production in Japan, the company was used in a commercial production led by the REDHILL Division of HAKUHODO PRODUCTS INC.
3）『 FUJIFILM Image Processing System IS-100 』
http://fujifilm.jp/business/broadcastcinema/solution/color_management/is-100/
4）CG artist Tatsuya Yamagishi and the author, who attended the seminar “Digital Shooting Workflow Revolution with IS-100 for Smooth Introduction of ACES Workflow” held at Nac Image Technology on July 26, 2012, promised Mr. Uchida and others to cooperate with ACES from the VFX side.
5）SMPTE STANDARD Academy Color Encoding Specification (ACES) – ST 2065-1:2012