Color grading
Encyclopedia
Color grading or colour painting, is the process of altering and enhancing the color of a motion picture, video
image, or still image either electronically, photo-chemically or digitally. The photo-chemical
process is also referred to as color timing and is typically performed at a photographic
laboratory
. Modern color correction, whether for theatrical film, video distribution, or print is generally done digitally in a color suite
. Considering such achievements in digital imaging, the artist has the ability to "paint" the image, thus the names "colorist" or "color painter" have become most applicable.
broadcasts and they turned to broadcasting feature film
s from release prints directly from a telecine
. This was in the days before 1956 when Ampex introduced the first Quadruplex videotape recorder (VTR) VRX-1000. Live television shows could also be recorded to film and aired at different times in different time zones by filming a video monitor. The heart of this system was the kinescope
, a device for recording a television broadcast to film.
The early telecine hardware was the "film chain
" for broadcasting from film and utilized a film projector connected to a video camera. As explained by Jay Holben in American Cinematographer Magazine, "The telecine didn't truly become a viable post-production
tool until it was given the ability to perform color correction on a video signal."
Today, telecine is synonymous with color timing as tools and technologies have advanced to make color timing (color correction) ubiquitous in a video environment.
(PMT), where the photons are converted into an electronic signal to be recorded to tape.
In a charge-coupled device
-(CCD) telecine, a “white” light is shone through the exposed film image into a prism, which separates out the image into the three primary colors, red, green and blue. Each beam of colored light is then projected at a different CCD, one for each color. The CCD converts the light into electrical impulses which the telecine electronics modulate into a video signal which can then be color-graded for use.
Early color correction on CRT Rank Cintel MkIII telecine
systems was accomplished by varying the primary gain voltages on each of the three photomultiplier tubes to vary the output of red, green and blue, respectively. Further advancements converted much of the color-processing equipment from analog to digital and then, with the next-generation telecine, the Ursa, the coloring process was completely digital in 4:2:2 color space
. The Ursa Gold brought about full 4:4:4 color space.
Color correction control systems started with the Rank Cintel TOPSY (Telecine Operations Programming SYstem) in 1978. In 1984 Da Vinci Systems
introduced their first color corrector, a computer-controlled interface that would manipulate the color voltages on the Rank Cintel MkIII systems. Since then, technology has improved to give extraordinary power to the digital colorist. Today there are many companies making color correction control interfaces including Da Vinci Systems
, Pandora International
Pogle and more.
Some of the main functions of electronic (digital) color grading:
Note that some of these functions are contrary to others. For example, color grading is often done to ensure that the recorded colors match those of the set design. In music videos however, the goal may instead be to establish a stylized look.
Traditionally, color grading was done towards technical goals. For example, in the film Marianne
, grading was used so that night scenes could be filmed more cheaply in daylight. Features like secondary color correction were originally used to establish color continuity. The trend today is increasingly moving towards creative goals - improving the aesthetics of an image, establishing stylized looks, and setting the mood of a scene through color. Because of this trend, some colorists suggest the phrase "color enhancement" over "color correction".
grading, objects and color ranges within the scene can be isolated with precision and adjusted. Color tints can be manipulated and visual treatments pushed to extremes not physically possible with laboratory processing. With these advancements, the color correction process became increasingly similar to well-established digital painting techniques, and ushered forth a new era of digital cinematography
.
Inside and outside of area-based isolations, digital filtration can be applied to soften, sharpen or mimic the effects of traditional glass photographic filters in nearly infinite degrees.
techniques used in special effects and compositing work.
Motion tracking can be combined with other techniques to add light to a subject's eyes or achieve the final look wanted for a scene. This not only saves time on the set (and money) but, when done in close collaboration with the cinematographer, allows greater flexibility in adjusting the overall feeling of the scene.
device into film scanning
allowed the digital information gathered from a film negative to be of sufficient resolution to transfer back to film. In the late 1990s, the films Pleasantville
and O Brother, Where Art Thou?
advanced the technology to the point that the creation of a digital intermediate
was possible, which greatly expanded the capabilities of the digital telecine colorist in a traditionally film-oriented world. Today, many feature films go through the DI process, while manipulation through photochemical processing is decreasing in use.
In Hollywood, O Brother, Where Art Thou?
was the first film to be wholly digitally graded. The negative was scanned with a Spirit DataCine
at 2K
resolution, then colors were digitally fine-tuned using a Pandora MegaDef color corrector on a Virtual DataCine. The process took several weeks, and the resulting digital master was output to film again with a Kodak laser recorder
to create a master internegative
.
The line between hardware and software is blurring as many software-based color correctors (e.g.Pablo http://www.quantel.com/page.php?u=5f855b42334dfa55ce0fdafa6c9dc127, Mistika
, SCRATCH http://assimilateinc.com/scratch.html, Autodesk Lustre, Digital Vision Film Master and Filmlight Baselight) use multi processor workstations and a GPU
(graphics processing unit) as a means of hardware acceleration
. As well, some newer software-based systems use specialized hardware to improve performance (e.g. da Vinci Resolve). Some color grading software like Synthetic Aperture's Color Finesse runs solely as a software based and will even run on low-end computer systems.
for the colorist to operate.
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
image, or still image either electronically, photo-chemically or digitally. The photo-chemical
Photochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
process is also referred to as color timing and is typically performed at a photographic
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
laboratory
Laboratory
A laboratory is a facility that provides controlled conditions in which scientific research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories...
. Modern color correction, whether for theatrical film, video distribution, or print is generally done digitally in a color suite
Color suite
Color suite also called a Color bay or a Telecine suite or Color correction bay. Color suite is the control room for color grading video in a post production environment. The video source could be from: a telecine, a Video tape recorder , a motion picture film scanner, virtual telecine or a Direct...
. Considering such achievements in digital imaging, the artist has the ability to "paint" the image, thus the names "colorist" or "color painter" have become most applicable.
Telecine
With the advent of television, broadcasters quickly realized the limitations of live televisionLive television
Live television refers to a television production broadcast in real-time, as events happen, in the present. From the early days of television until about 1958, live television was used heavily, except for filmed shows such as I Love Lucy and Gunsmoke. Video tape did not exist until 1957...
broadcasts and they turned to broadcasting feature film
Feature film
In the film industry, a feature film is a film production made for initial distribution in theaters and being the main attraction of the screening, rather than a short film screened before it; a full length movie...
s from release prints directly from a telecine
Telecine
Telecine is transferring motion picture film into video and is performed in a color suite. The term is also used to refer to the equipment used in the post-production process....
. This was in the days before 1956 when Ampex introduced the first Quadruplex videotape recorder (VTR) VRX-1000. Live television shows could also be recorded to film and aired at different times in different time zones by filming a video monitor. The heart of this system was the kinescope
Kinescope
Kinescope , shortened to kine , also known as telerecording in Britain, is a recording of a television program made by filming the picture from a video monitor...
, a device for recording a television broadcast to film.
The early telecine hardware was the "film chain
Film chain
A film chain or film island is a television - Professional video camera with one or more projectors aligned into the photographic lens of the camera. With two or more projectors a system of front-surface mirrors that can pop-up are used in a multiplexer. These mirrors switch different projectors...
" for broadcasting from film and utilized a film projector connected to a video camera. As explained by Jay Holben in American Cinematographer Magazine, "The telecine didn't truly become a viable post-production
Post-production
Post-production is part of filmmaking and the video production process. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art...
tool until it was given the ability to perform color correction on a video signal."
Today, telecine is synonymous with color timing as tools and technologies have advanced to make color timing (color correction) ubiquitous in a video environment.
How telecine coloring works
In a Cathode-ray tube (CRT) system, an electron beam is projected at a phosphor-coated envelope, producing a beam of light the size of a single pixel. This beam is then scanned across a film frame from left to right, capturing the "vertical" frame information. Horizontal scanning of the frame is then accomplished as the film moves past the CRT's beam. Once this photon beam passes through the film frame, it encounters a series of dichroic mirrors which separate the image into its primary red, green and blue components. From there, each individual beam is then reflected on to a photomultiplier tubePhotomultiplier
Photomultiplier tubes , members of the class of vacuum tubes, and more specifically phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum...
(PMT), where the photons are converted into an electronic signal to be recorded to tape.
In a charge-coupled device
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
-(CCD) telecine, a “white” light is shone through the exposed film image into a prism, which separates out the image into the three primary colors, red, green and blue. Each beam of colored light is then projected at a different CCD, one for each color. The CCD converts the light into electrical impulses which the telecine electronics modulate into a video signal which can then be color-graded for use.
Early color correction on CRT Rank Cintel MkIII telecine
Telecine
Telecine is transferring motion picture film into video and is performed in a color suite. The term is also used to refer to the equipment used in the post-production process....
systems was accomplished by varying the primary gain voltages on each of the three photomultiplier tubes to vary the output of red, green and blue, respectively. Further advancements converted much of the color-processing equipment from analog to digital and then, with the next-generation telecine, the Ursa, the coloring process was completely digital in 4:2:2 color space
Color space
A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components...
. The Ursa Gold brought about full 4:4:4 color space.
Color correction control systems started with the Rank Cintel TOPSY (Telecine Operations Programming SYstem) in 1978. In 1984 Da Vinci Systems
Da Vinci Systems
da Vinci Systems is a main manufacturer of high-end post-production color grading and film restoration systems for feature films, video production and broadcast post-production facilities...
introduced their first color corrector, a computer-controlled interface that would manipulate the color voltages on the Rank Cintel MkIII systems. Since then, technology has improved to give extraordinary power to the digital colorist. Today there are many companies making color correction control interfaces including Da Vinci Systems
Da Vinci Systems
da Vinci Systems is a main manufacturer of high-end post-production color grading and film restoration systems for feature films, video production and broadcast post-production facilities...
, Pandora International
Pandora International
Pandora International is a maker of hardware and software. Pandora International devices are able to color correct video and 16mm and 35mm motion picture film transfered through it'sdevices. Pandora International is based in Greenhithe, Kent, England....
Pogle and more.
Some of the main functions of electronic (digital) color grading:
- Reproduce accurately what was shot
- Compensate for variations in the material (i.e. film errors, white balance, varying lighting conditions)
- Optimize transfer for use of special effects
- Establish a desired 'look'
- Enhance and/or alter the mood of a scene — the visual equivalent to the musical accompaniment of a film; compare also film tintingFilm tintingFilm tinting is the process of adding color to black-and-white film, usually by means of soaking the film in dye and staining the film emulsion...
.
Note that some of these functions are contrary to others. For example, color grading is often done to ensure that the recorded colors match those of the set design. In music videos however, the goal may instead be to establish a stylized look.
Traditionally, color grading was done towards technical goals. For example, in the film Marianne
Marianne (2011 film)
Marianne is a 2011 Swedish horror film, directed by Filip Tegstedt, that premiered at the 2011 Fantasia International Film Festival on 2 August 2011....
, grading was used so that night scenes could be filmed more cheaply in daylight. Features like secondary color correction were originally used to establish color continuity. The trend today is increasingly moving towards creative goals - improving the aesthetics of an image, establishing stylized looks, and setting the mood of a scene through color. Because of this trend, some colorists suggest the phrase "color enhancement" over "color correction".
Primary and secondary color correction
Primary color correction affects the whole image utilizing control over intensities of red, green, blue, gamma (mid tones), shadows (blacks) and highlights (whites) of the entire frame. Secondary correction is based on the same types of processing used for Chroma Keying to isolate a range of color, saturation and brightness values to bring about alterations in luminance, saturation and hue in only that range, while having a minimal or usually no effect on the remainder of the color spectrum. Using digitalDigital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
grading, objects and color ranges within the scene can be isolated with precision and adjusted. Color tints can be manipulated and visual treatments pushed to extremes not physically possible with laboratory processing. With these advancements, the color correction process became increasingly similar to well-established digital painting techniques, and ushered forth a new era of digital cinematography
Digital cinematography
Digital cinematography is the process of capturing motion pictures as digital images, rather than on film. Digital capture may occur on video tape, hard disks, flash memory, or other media which can record digital data. As digital technology has improved, this practice has become increasingly common...
.
Masks, Mattes, Power Windows
The evolution of digital color correction tools advanced to the point where the colorist could use geometric shapes (like mattes or masks in photo software such as Photoshop) to isolate color adjustments to specific areas of an image. These tools can highlight a wall in the background and color only that wall — leaving the rest of the frame alone — or color everything but that wall. Subsequent color correctors (typically software-based) have the ability to use spline-based shapes for even greater control over isolating color adjustments. Color keying is also used for isolating areas to adjust.Inside and outside of area-based isolations, digital filtration can be applied to soften, sharpen or mimic the effects of traditional glass photographic filters in nearly infinite degrees.
Motion Tracking
When trying to isolate a color adjustment on a moving subject, the colorist traditionally would have needed to manually move the mask to follow the subject. In its most simple form, motion tracking automates this time-consuming process using algorithms to evaluate the motion of a group of pixels. These techniques are generally derived from match movingMatch moving
In cinematography, match moving is a visual-effects, cinematic techniques that allows the insertion of computer graphics into live-action footage with correct position, scale, orientation, and motion relative to the photographed objects in the shot...
techniques used in special effects and compositing work.
Motion tracking can be combined with other techniques to add light to a subject's eyes or achieve the final look wanted for a scene. This not only saves time on the set (and money) but, when done in close collaboration with the cinematographer, allows greater flexibility in adjusting the overall feeling of the scene.
DI
The evolution of the telecineTelecine
Telecine is transferring motion picture film into video and is performed in a color suite. The term is also used to refer to the equipment used in the post-production process....
device into film scanning
Motion picture film scanner
A motion picture film scanner is a device used in digital filmmaking to scan original film for storage as high-resolution digital intermediate files.A film scanner scans original film stock: negative or positive print or reversal/IP...
allowed the digital information gathered from a film negative to be of sufficient resolution to transfer back to film. In the late 1990s, the films Pleasantville
Pleasantville (film)
Pleasantville is a 1998 American fantasy comedy-drama film written, produced, and directed by Gary Ross. The film stars Tobey Maguire, Reese Witherspoon, William H. Macy, Joan Allen, Marley Shelton and Jeff Daniels. Don Knotts, Paul Walker, Jane Kaczmarek, and J. T. Walsh are also featured.The film...
and O Brother, Where Art Thou?
O Brother, Where Art Thou?
O Brother, Where Art Thou? is a 2000 comedy film directed by Joel and Ethan Coen and starring George Clooney, John Turturro, Tim Blake Nelson, John Goodman, Holly Hunter, and Charles Durning. Set in 1937 rural Mississippi during the Great Depression, the film's story is a modern satire loosely...
advanced the technology to the point that the creation of a digital intermediate
Digital intermediate
Digital intermediate is a motion picture finishing process which classically involves digitizing a motion picture and manipulating the color and other image characteristics. It often replaces or augments the photochemical timing process and is usually the final creative adjustment to a movie...
was possible, which greatly expanded the capabilities of the digital telecine colorist in a traditionally film-oriented world. Today, many feature films go through the DI process, while manipulation through photochemical processing is decreasing in use.
In Hollywood, O Brother, Where Art Thou?
O Brother, Where Art Thou?
O Brother, Where Art Thou? is a 2000 comedy film directed by Joel and Ethan Coen and starring George Clooney, John Turturro, Tim Blake Nelson, John Goodman, Holly Hunter, and Charles Durning. Set in 1937 rural Mississippi during the Great Depression, the film's story is a modern satire loosely...
was the first film to be wholly digitally graded. The negative was scanned with a Spirit DataCine
Spirit DataCine
Spirit DataCine is a telecine and/or a motion picture film scanner. This device is able to transfer 16mm and 35mm motion picture film to NTSC or PAL standards or one of many High-definition television standards. With the data transfer option a Spirit DataCine can output DPX data files. The Spirit...
at 2K
Digital cinema
Digital cinema refers to the use of digital technology to distribute and project motion pictures. A movie can be distributed via hard drives, optical disks or satellite and projected using a digital projector instead of a conventional film projector...
resolution, then colors were digitally fine-tuned using a Pandora MegaDef color corrector on a Virtual DataCine. The process took several weeks, and the resulting digital master was output to film again with a Kodak laser recorder
Film-out
Film-out is the process in the computer graphics, video production and filmmaking disciplines of transferring images or animation from videotape or digital files to a traditional film print...
to create a master internegative
Internegative
An internegative is a motion picture film duplicate. It is the color counterpart to an interpositive, in which a low-contrast color image is used as the positive between an original camera negative and a duplicate negative....
.
Hardware-based versus software-based systems
Hardware-based systems (da Vinci 2K, Pandora, etc.) have historically offered better performance and a smaller feature set than software-based systems (i.e. Apple's Color (previously Silicon Color Final Touch), ASSIMILATE SCRATCH, IRIDAS SpeedGrade, SGO Mistika, etc.). While hardware-based systems always offer real-time performance, software-based systems need to render as the complexity of the color grading increases. On the other hand, software-based systems tend to have more features such as spline-based windows/masks and advanced motion tracking.The line between hardware and software is blurring as many software-based color correctors (e.g.Pablo http://www.quantel.com/page.php?u=5f855b42334dfa55ce0fdafa6c9dc127, Mistika
Mistika
Mistika is a post-production software published by . It has gained a lot of new users in the past couple of years, especially when compared to its main competitors Autodesk Lustre, Quantel Pablo, Filmlight Baselight, with users becoming very loyal as the system is unique in operation and design.-...
, SCRATCH http://assimilateinc.com/scratch.html, Autodesk Lustre, Digital Vision Film Master and Filmlight Baselight) use multi processor workstations and a GPU
Graphics processing unit
A graphics processing unit or GPU is a specialized circuit designed to rapidly manipulate and alter memory in such a way so as to accelerate the building of images in a frame buffer intended for output to a display...
(graphics processing unit) as a means of hardware acceleration
Hardware acceleration
In computing, Hardware acceleration is the use of computer hardware to perform some function faster than is possible in software running on the general-purpose CPU...
. As well, some newer software-based systems use specialized hardware to improve performance (e.g. da Vinci Resolve). Some color grading software like Synthetic Aperture's Color Finesse runs solely as a software based and will even run on low-end computer systems.
Hardware
The control panels are placed in a color suiteColor suite
Color suite also called a Color bay or a Telecine suite or Color correction bay. Color suite is the control room for color grading video in a post production environment. The video source could be from: a telecine, a Video tape recorder , a motion picture film scanner, virtual telecine or a Direct...
for the colorist to operate.
- For high-end systems many telecines are controlled by a Da Vinci SystemsDa Vinci Systemsda Vinci Systems is a main manufacturer of high-end post-production color grading and film restoration systems for feature films, video production and broadcast post-production facilities...
color corrector 2k or 2k Plus, which is also called color grading. - Other high-end systems are controlled by Pandora Int.'s Pogle, often with either a MegaDEF, Pixi, or Revolution color grading system.
- Additionally, color grading systems require an edit controller. The edit controller controls the telecine and a VTR(s) or other recording/playback devices to ensure frame accurate film frame editingNon-linear editing systemIn video, a non-linear editing system is a video editing or audio editing digital audio workstation system which can perform random access non-destructive editing on the source material...
. There are a number of systems which can be used for edit control. Some color grading products such as Pandora Int.'s Pogle have a built in edit controller. Otherwise, a separate device such as Da Vinci SystemsDa Vinci Systemsda Vinci Systems is a main manufacturer of high-end post-production color grading and film restoration systems for feature films, video production and broadcast post-production facilities...
' TLC edit controller would be used. - Older systems are: Renaissance, Classic analog, Da Vinci SystemsDa Vinci Systemsda Vinci Systems is a main manufacturer of high-end post-production color grading and film restoration systems for feature films, video production and broadcast post-production facilities...
's: The Whiz (1982) and 888; The Corporate Communications's System 60XL (1982–1989) and Copernicus-Sunburst; Bosch FernsehFernsehThe Fernseh AG television company was registered in Berlin on July 3, 1929 by John Logie Baird, Robert Bosch and other partners with an initial capital of 100,000 Reichsmark....
's FRP-60 (1983–1989); Dubner (1978-1985?), CintelCintelCintel International Ltd is a British company, based in Ware, Hertfordshire,SG12 0AE, which specialises in the design and manufacture of professional post-production equipment, for transcribing film into video or data formats...
's TOPSY (1978), Amigo (1983), and ARCAS (1992) systems. All of these older systems work only with standard-definition 525480i480i is the shorthand name for a video mode, namely the US NTSC television system or digital television systems with the same characteristics. The i, which is sometimes uppercase, stands for interlaced, the 480 for a vertical frame resolution of 480 lines containing picture information; while NTSC...
and 625576i576i is a standard-definition video mode used in PAL and SECAM countries. In digital applications it is usually referred to as "576i", in analogue contexts it is often quoted as "625 lines"...
video signals, and are considered near obsolete today.
Software
The controls are shown on-screen and are sometimes accessed as plugin in a host application.- Software like Synthetic Aperture's Color Finesse runs as a plugin in host applications like Apple's Final Cut Pro, Adobe's After Effects and Premiere.
- Magic Bullet Colorista II http://www.redgiantsoftware.com/products/all/magic-bullet-colorista-II/ from Red Giant Software offers multi-step color correction with primary, secondary and master stages inside host applications including Apple's Final Cut Pro, Adobe's After Effects and Premiere.
- The Grading Sweet is a package of specialized Color Grading plugins for Apple's Final Cut Pro, designed by a cinematographer.
- Sony Vegas has many filters that can provide professional quality color grading.
- Apple Final Cut Studio 2 Contains Apple Color http://www.apple.com/finalcutstudio/color/ which is a dedicated software application for color grading.
- Bones Dailies by Digital Film TechnologySpirit DataCineSpirit DataCine is a telecine and/or a motion picture film scanner. This device is able to transfer 16mm and 35mm motion picture film to NTSC or PAL standards or one of many High-definition television standards. With the data transfer option a Spirit DataCine can output DPX data files. The Spirit...
- Other programs have their own color grading options (for example Edius, in which there is a "Color Correction" video effect - with it, you can do a "day to night*" effect (turning footage shot during the day to look like it was shot during the night).
- Autodesk Lustre is another high-end color grading solution. It features GPU acceleration for most functions.
- Mistika (SGO) is a powerful color grading suite.
- Baselight from FilmLightFilmlightFilmLight Limited is a digital cinema technology company started in 2002 by the Scientific and Technical Academy Award-winning former Computer Film Company R&D team.Their main products are:...
is often used for Stereo3D and 4K color grading because of its powerful cluster architecture.
External links
- "From One Light To Final Grade", and other articles from finalcolor.com about color grading techniques and equipment
- Video demo of Autodesk Lustre at IBC 2006, using the example of grading "Tsotsi", the South African film from 2005.
- The Telecine Internet Group, since 1992 with associated mailinglist for colorists.
- The Art and Craft of Color Grading, blog by Dado Valentic chief colorist at Mytherapy.