Saturday 26 May 2012

Color grading

Color allocation or colour painting, is the action of altering and acceptable the blush of a motion picture, video image, or still angel either electronically, photo-chemically or digitally. The photo-chemical action is aswell referred to as blush timing and is about performed at a accurate laboratory. Modern blush correction, whether for affected film, video distribution, or book is about done digitally in a blush suite. Considering such achievements in agenda imaging, the artisan has the adeptness to "paint" the image, appropriately the names "colorist" or "color painter" accept become a lot of applicable.

Telecine


With the appearance of television, broadcasters bound able the limitations of reside television broadcasts and they angry to broadcasting affection films from absolution prints anon from a telecine. This was in the canicule afore 1956 if Ampex alien the aboriginal Quadruplex cine recorder (VTR) VRX-1000. Reside television shows could aswell be recorded to blur and aired at altered times in altered time zones by filming a video monitor. The affection of this arrangement was the kinescope, a accessory for recording a television advertisement to film.1

The aboriginal telecine accouterments was the "film chain" for broadcasting from blur and activated a blur projector affiliated to a video camera. As explained by Jay Holben in American Cinematographer Magazine, "The telecine didn't absolutely become a applicable post-production apparatus until it was accustomed the adeptness to accomplish blush alteration on a video signal."2

Today, telecine is alike with blush timing as accoutrement and technologies accept avant-garde to accomplish blush timing (color correction) all-over in a video environment.

editHow telecine appearance works

In a Cathode-ray tube (CRT) system, an electron axle is projected at a phosphor-coated envelope, bearing a axle of ablaze the admeasurement of a abandoned pixel. This axle is again scanned beyond a blur anatomy from larboard to right, capturing the "vertical" anatomy information. Horizontal scanning of the anatomy is again able as the blur moves able the CRT's beam. Once this photon axle passes through the blur frame, it encounters a alternation of dichroic mirrors which abstracted the angel into its primary red, blooming and dejected components. From there, anniversary abandoned axle is again reflected on to a photomultiplier tube (PMT), area the photons are adapted into an cyberbanking arresting to be recorded to tape.

In a charge-coupled device-(CCD) telecine, a “white” ablaze is shone through the apparent blur angel into a prism, which separates out the angel into the three primary colors, red, blooming and blue. Anniversary axle of black ablaze is again projected at a altered CCD, one for anniversary color. The CCD converts the ablaze into electrical impulses which the telecine electronics attune into a video arresting which can again be color-graded for use.

Early blush alteration on CRT Rank Cintel MkIII telecine systems was able by capricious the primary accretion voltages on anniversary of the three photomultiplier tubes to adapt the achievement of red, blooming and blue, respectively. Further advancements adapted abundant of the color-processing accessories from analog to agenda and then, with the next-generation telecine, the Ursa, the appearance action was absolutely agenda in 4:2:2 blush space. The Ursa Gold brought about abounding 4:4:4 blush space.2

Color alteration ascendancy systems started with the Rank Cintel TOPSY (Telecine Operations Programming SYstem) in 1978.1 In 1984 Da Vinci Systems alien their aboriginal blush corrector, a computer-controlled interface that would dispense the blush voltages on the Rank Cintel MkIII systems. Since then, technology has bigger to accord amazing adeptness to the agenda colorist. Today there are abounding companies authoritative blush alteration ascendancy interfaces including Da Vinci Systems, Pandora_International Pogle and more.

Some of the capital functions of cyberbanking (digital) blush grading:1

Reproduce accurately what was shot

Compensate for variations in the actual (i.e. blur errors, white balance, capricious lighting conditions)

Optimize alteration for use of appropriate effects

Establish a adapted 'look'

Enhance and/or adapt the affection of a arena — the beheld agnate to the agreeable accessory of a film; analyze aswell blur tinting.

Note that some of these functions are adverse to others. For example, blush allocation is about done to ensure that the recorded colors bout those of the set design. In music videos however, the ambition may instead be to authorize a august look.

Traditionally, blush allocation was done appear abstruse goals. For example, in the blur Marianne, allocation was acclimated so that night scenes could be filmed added cheaply in daylight. Features like accessory blush alteration were originally acclimated to authorize blush continuity. The trend today is more affective appear artistic goals - convalescent the aesthetics of an image, establishing august looks, and ambience the affection of a arena through color. Because of this trend, some colorists advance the byword "color enhancement" over "color correction".

editPrimary and accessory blush correction

Primary blush alteration affects the accomplished angel utilizing ascendancy over intensities of red, green, blue, gamma (mid tones), caliginosity (blacks) and highlights (whites) of the absolute frame. Accessory alteration is based on the aforementioned types of processing acclimated for Chroma Keying to abstract a ambit of color, assimilation and accuracy ethics to accompany about alterations in luminance, assimilation and hue in abandoned that range, while accepting a basal or usually no aftereffect on the butt of the blush spectrum.1 Application agenda grading, altar and blush ranges aural the arena can be abandoned with attention and adjusted. Blush tints can be manipulated and beheld treatments pushed to extremes not physically accessible with class processing. With these advancements, the blush alteration action became more agnate to absolute agenda painting techniques, and ushered alternating a new era of agenda cinematography.

editMasks, Mattes, Adeptness Windows

The change of agenda blush alteration accoutrement avant-garde to the point area the colorist could use geometric shapes (like mattes or masks in photo software such as Photoshop) to abstract blush adjustments to specific areas of an image. These accoutrement can highlight a bank in the accomplishments and blush abandoned that bank — abrogation the blow of the anatomy abandoned — or blush aggregate but that wall. Subsequent blush correctors (typically software-based) accept the adeptness to use spline-based shapes for even greater ascendancy over isolating blush adjustments. Blush keying is aswell acclimated for isolating areas to adjust.

Inside and alfresco of area-based isolations, agenda filtration can be activated to soften, acuminate or actor the furnishings of acceptable bottle accurate filters in about absolute degrees.

editMotion Tracking

When aggravating to abstract a blush acclimation on a affective subject, the colorist commonly would accept bare to manually move the affectation to chase the subject. In its a lot of simple form, motion tracking automates this time-consuming action application algorithms to appraise the motion of a accumulation of pixels. These techniques are about acquired from bout affective techniques acclimated in appropriate furnishings and compositing work.

Motion tracking can be accumulated with added techniques to add ablaze to a subject's eyes or accomplish the final attending capital for a scene. This not abandoned saves time on the set (and money)citation needed but, if done in abutting accord with the cinematographer, allows greater adaptability in adjusting the all-embracing activity of the scene.

DI


The change of the telecine accessory into blur scanning accustomed the agenda advice aggregate from a blur abrogating to be of acceptable resolution to alteration aback to film. In the backward 1990s, the films Pleasantville and O Brother, Where Art Thou? avant-garde the technology to the point that the conception of a agenda average was possible, which abundantly broadcast the capabilities of the agenda telecine colorist in a commonly film-oriented world. Today, abounding affection films go through the DI process, while abetment through photochemical processing is abbreviating in use.

In Hollywood, O Brother, Where Art Thou? was the aboriginal blur to be wholly digitally graded. The abrogating was scanned with a Spirit DataCine at 2K resolution, afresh colors were digitally fine-tuned application a Pandora MegaDef blush corrector on a Virtual DataCine‎. The action took several weeks, and the consistent agenda adept was achievement to blur afresh with a Kodak laser recorder to actualize a adept internegative.

Hardware-based versus software-based systems


Hardware-based systems (da Vinci 2K, Pandora, etc.) accept historically offered bigger achievement and a abate affection set than software-based systems (i.e. Apple's Blush (previously Silicon Blush Final Touch), ASSIMILATE SCRATCH, IRIDAS SpeedGrade, SGO Mistika, etc.). While hardware-based systems consistently action real-time performance, software-based systems charge to cede as the complication of the blush allocation increases. On the added hand, software-based systems tend to accept added appearance such as spline-based windows/masks and avant-garde motion tracking.

The band amid accouterments and software is abashing as abounding software-based blush correctors (e.g.Pablo 1, Mistika, SCRATCH 2, Autodesk Lustre, Nucoda Blur Adept and Filmlight Baselight) use multi processor workstations and a GPU (graphics processing unit) as a agency of accouterments acceleration. As well, some newer software-based systems use specialized accouterments to advance achievement (e.g. da Vinci Resolve). Some blush allocation software like Synthetic Aperture's Blush Finesse runs alone as a software based and will even run on low-end computer systems.

editHardware

"Pogle" redirects here. For added uses, see Pogle (disambiguation).

The ascendancy panels are placed in a blush apartment for the colorist to operate.

For high-end systems manycitation needed telecines are controlled by a Da Vinci Systems blush corrector 2k or 2k Plus, which is aswell alleged blush grading.

Other high-end systems are controlled by Pandora Int.'s Pogle, generally with either a MegaDEF, Pixi, or Revolution blush allocation system.

Additionally, blush allocation systems crave an adapt controller. The adapt ambassador controls the telecine and a VTR(s) or added recording/playback accessories to ensure anatomy authentic blur anatomy editing. There are a amount of systems which can be acclimated for adapt control. Some blush allocation articles such as Pandora Int.'s Pogle accept a congenital in adapt controller. Otherwise, a abstracted accessory such as Da Vinci Systems' TLC adapt ambassador would be used.

Older systems are: Renaissance, Classic analog, Da Vinci Systems's: The Whiz (1982) and 888; The Corporate Communications's Arrangement 60XL (1982–1989) and Copernicus-Sunburst; Bosch Fernseh's FRP-60 (1983–1989); Dubner (1978-1985?), Cintel's TOPSY (1978), Amigo (1983), and ARCAS (1992) systems. All of these earlier systems plan alone with standard-definition 525 and 625 video signals, and are advised abreast anachronistic today.

editSoftware

The controls are apparent on-screen and are sometimes accessed as plugin in a host application.

Software like Synthetic Aperture's Blush Finesse runs as a plugin in host applications like Apple's Final Cut Pro, Adobe's After Effects and Premiere.

Magic Bullet Colorista II 3 from Red Giant Software offers multi-step blush alteration with primary, accessory and adept stages central host applications including Apple's Final Cut Pro, Adobe's After Effects and Premiere.

The Allocation Sweet is a amalgamation of specialized Blush Allocation plugins for Apple's Final Cut Pro, advised by a cinematographer.

Sony Vegas has abounding filters that can accommodate able superior blush grading.

Apple Final Cut Studio 2 Contains Apple Blush 4 which is a committed software appliance for blush grading.

Da Vinci Systems Resolve is a high-end color-grading system, generally acclimated as a arrive band-aid for its versatility in compositing and telecine control.

Bones Dailies by Digital Blur Technology

Other programs accept their own blush allocation options (for archetype Edius, in which there is a "Color Correction" video aftereffect - with it, you can do a "day to night*" aftereffect (turning footage attempt during the day to attending like it was attempt during the night).

Autodesk Lustre is addition high-end blush allocation solution. It appearance GPU dispatch for a lot of functions.

Nucoda Blur Adept from Image Systems provides colour allocation accoutrement as able-bodied as abounding apology tools.

Mistika (SGO) is a able blush allocation suite.

Baselight from FilmLight is generally acclimated for Stereo3D and 4K blush allocation because of its able array architecture.

Da Vinci Joy brawl ascendancy panel

Da Vinci 2k Display

Pogle ascendancy console and bendable bulge display

Pogle SGI adviser display

Pogle ascendancy console and keyboard

Pogle ascendancy console joyballs

Pogle MegaDEF: Two PiXi systems with a multiplexer rack

Pogle ascendancy rack, CPU and Telecine inferface

Bosch Fernseh FDL 60 Telecine Blur Deck and Lens Gate

SDC-2000 Spirit DataCine Blur Deck

Rank Cintel Mark 3

Cintel URSA Diamond