Color and imaging science

Color management, HDR, transforms, calibration, film looks and image quality

• articleDoes Unity Recorder 5.1.7 tonemap or colour-tag the frames it saves, and which Color Space option should I pick?
  Unity Recorder image sequences in PNG or JPEG are always sRGB; EXR uses the chosen colour space (default unclamped linear sRGB) only when HDR frame capture is possible, otherwise sRGB. Tonemapping is whatever the render pipeline applied (docs advise disabling it for linear output, producer reading).
• articleI have a Canon Log 3, S-Log3 or V-Log clip and want to know which constants in an open transform I can check against the manufacturer's document, and which I must take on trust?
  Curve constants can be checked against vendor documents for Sony, Panasonic and Canon (CA-B219) as well as ARRI and RED. Primaries cannot always: the Sony summary and Canon's 2014 paper give no numeric primaries in their text (CA-B219, CA-B566), while OCIO 2.6 and ACES carry S-Gamut3, S-Gamut3.Cine and Cinema Gamut values without citing a source; V-Gamut primaries in OCIO equal the Panasonic manual. Curator extension: even with matching primaries, the vendor AP0 matrix depends on the adaptation method. Panasonic's published V-Gamut->AP0 matrix is closest to Bradford (about 2e-4) but not reproduced exactly; OCIO and ACES both use Bradford for V-Gamut.
• articleWhat does an ACES Metadata File (AMF) record at its published version 2.0 and what is optional versus required?
  AMF v2.0 (schema at aces-amf e2b99012) is an XML sidecar describing one ACES viewing pipeline: only amfInfo (with dateTime and a UUID) and a pipeline with pipelineInfo/systemVersion are required; clipId, the input transform, any number of ordered look transforms (CDL embedded with a declared working space, CDL referenced by ID from a file, or a CLF/other transform), an optional workingLocation marker and an optional output transform may follow, and earlier pipelines are kept as repeated archivedPipeline elements. The version attribute is fixed at 2.0. The user guide (list dated 21 July 2025) names Pomfort, Colorfront, Resolve 19.1+ and Baselight 6.0+ as exporters; per-tool behaviour was not tested. Conflict within the AMF work: the spec page gives applied="false" as the default, while the XSD makes the applied attribute required on input, look and output transforms. Writers should always emit applied explicitly.
• articleWhat do the built-in OCIO ACES CG and Studio configs for ACES 1.3 and ACES 2.0 contain, and how do their views and displays differ?
  OCIO 2.6 ships three generations of ACES CG configs: ACES 1.3 (v2.2.0, needs OCIO 2.4+), ACES 2.0 (v4.0.0, OCIO 2.5+) and ACES 2.1 (v5.0.0, OCIO 2.6+, now the default). Comparing the 1.3 and 2.0 CG configs, the roles are the same (ACEScg scene-linear, ACES2065-1 interchange, sRGB-encoded colour picking). The view transforms change from ACES 1.0/1.1 names to 'ACES 2.0 - SDR 100 nits / HDR 1000 nits'. Colour spaces are tagged with ColorInterop interop_id instead of ACEStransformID, and viewing rules are added. The Config-ACES v4.0.0 release (October 2025) also adds AMF transform IDs and mirrored displays, flagged as a breaking change. Apply views through a DisplayViewTransform, not a ColorSpaceTransform.
• articleWhat actually helped in an 8-day AI video-editing trial (Jun 2026): editor plugins, agent-made B-roll, Claude + HyperFrames motion graphics, Omni footage edits
  Creator-reported: statements attributed to the creator(s) come from discovery's reading of auto-caption transcript excerpts; the curator checked the video metadata (title, date, length) and any cited documentation pages, not the spoken claims. Nothing was tested; promotional or sponsored framing applies where stated. Dan Kieft and team (2026-06-12) sorted tools into money-saving, speed and creativity. Useful: Higgsfield plugins inside Premiere Pro, After Effects and Figma (generate shots, reframe 16:9 to vertical, 4K upscale; background removal "mixed results"); Higgsfield "Supercomputer" agent producing intro scenes and B-roll/infographic "cards" for explainers, with failures retried on request; Claude Code + HyperFrames (HeyGen's Apache-2.0 open-source HTML-to-video renderer "built for agents", R6) to add titles, captions, lists, counters and UI animations around a raw talking-head recording by describing them, then iterating in plain language ("make the transition faster"); Googl...
• articleDo the content-light statistics x265 computes match the H.265 definition of MaxCLL and MaxFALL?
  By reading code against D.3.35, the x265 statistics differ from the spec rule in three ways: they use the Y (luma) plane code values, not per-pixel max(R,G,B) in linear light scaled to cd/m2; the frame average is over the whole stored frame; and the reported MaxFALL is the mean of frame averages, not the maximum. This is a code-derived inference about the statistics, not a statement about what x265 writes in the SEI, which comes from the --max-cll option. No execution was done.
• articleWhat exactly does WCAG 2.2 SC 1.4.3 require for text contrast, and how do I apply it as a check to AI-generated posters, title cards and thumbnails?
  Problem. Generated backgrounds are busy, and text laid over them often fails contrast. Conditions. WCAG 2.2 Understanding document for SC 1.4.3 (Level AA); it governs web content, so for posters and thumbnails it is a benchmark, not a legal rule. Method (documented). Text and images of text need a contrast ratio of at least 4.5:1, except large-scale text at 3:1; the Understanding text says 18 point text or 14 point bold text is judged to be large; computed values are not rounded (4.499:1 fails 4.5:1); text that is part of a logo or logotype is exempt; the document notes images of text do not scale well because they pixelate. Relative-luminance formula details are in C3-B066-G25-04 and C2-B22-E3-03. Checks on AI graphics [inference]. (1) After setting type (C3-B593-03), sample the background pixels under each glyph box, not the average of the image, and compute the ratio for the lightest and darkest background pixel against the text colour; the worst case must pass. (2) Gradients and...
• articleHow much do pixels differ across GPUs and browsers for the same WebGL or WebGPU scene, and what tolerance do conformance tests allow?
  A 2012 study rendered one simple antialiased WebGL scene on 270 crowd-sourced machines: the images looked identical but formed 50 distinct pixel-level renders, mostly consistent within a graphics-card model (the text also mentions 51 groups). Current WebGPU conformance tests assume small differences: integer formats compare exactly by default, float and normalised formats can use ULP or fractional thresholds, a canvas colour-space reftest allows up to 2 levels per channel, and WGSL leaves the rounding mode open when quantising. So pixel-exact equality across devices should not be expected; no recent cross-device measurement was found.
• articleWhich palette and exact-colour controls do FLUX, Recraft and Ideogram document, and how should I verify that a generated image kept the brand colours?
  Problem. Brand work needs specific colours; prompts alone drift. Conditions. FLUX.2 / FLUX 3 (BFL), Recraft API, Ideogram 3.0 API, docs of 23 Oct 2026. Method (documented). BFL: hex codes name exact colours in FLUX.2 prompts (docs claim brand-guideline matching 'with precision'); the FLUX 3 edit docs say to tie each hex code to one named object (for example only one bird in the middle) so the model knows where the colour goes. Recraft: controls.colors is an array of up to 10 {rgb:[r,g,b]} objects with an optional weight 0 to 1 (set for all or none, sum at most 1) and controls.background_color; the docs call them 'preferable colors'. A palette can also be stored with a style (Create style). Ideogram 3.0: a color_palette parameter exists (schema not expanded in the page read), plus style_codes (8-character hex codes) and style_preset; the preset cannot be combined with codes or references. Verify [inference]. Sample the output in sRGB, cluster to the dominant five to eight colours, an...
• articleWhat do open AI video tools (Wan2.2 save_video, diffusers export_to_video) actually write to the file: bit depth, encoder, colour tags, resolution?
  Problem. A generated clip looks different after export (banding, size change, shifted levels) and nobody knows what the tool did. Conditions. Python tools that write MP4 through imageio/ffmpeg. Method (read from code). Wan2.2 wan/utils/utils.py save_video: tensor clamped to value_range (-1,1), made into a grid per frame, multiplied by 255 and cast with .type(torch.uint8), written with imageio.get_writer(codec='libx264', quality=8); fps default 30 in the signature. diffusers export_utils.export_to_video: float numpy frames become (frame*255).astype(np.uint8); imageio.get_writer with quality default 5 (variable bit rate; 10 highest), optional bitrate, and macro_block_size default 16, where imageio tells ffmpeg to scale the image up to the next size divisible by that number; set None or 1 to disable, with the warning that many players cannot decode odd sizes. Observations: (a) 8-bit output, so banding risk (C3-B586-01/02); (b) float to uint8 is a cast, not documented as rounded or dith...
• articleHow should I bring an SDR AI plate (MP4, PNG) into an OCIO/ACES or Resolve colour-managed timeline: as display-referred or scene-linear, and which OCIO roles and rules matter?
  Problem. AI plates are rendered pictures with no camera log or scene-referred metadata, yet colour-managed timelines expect an input colour space. Conditions. OCIO v2 configs (docs 'latest' at 2026-10-23, CG config based on ACES 2.1); applies to any OCIO application. Method. OCIO documentation facts: a config has Roles, File & Viewing rules, Displays & Views, Looks, scene-referred Colorspaces, Display Colorspaces and Named Transforms; the CG config says baking in an ACES Output Transform needs a DisplayViewTransform rather than a ColorSpaceTransform, because applying a view transform is a different process from converting between colour space encodings; the data role should use a colour space with data: true so no transforms are applied; the default role is the fallback colour space only when strictparsing is false; ociocheck detects undefined colour spaces and roles; the authoring guide warns that applications vary in how they interpret roles. Workflow [inference, three cases]. (A)...
• articleHow can I measure and match colour and brightness between separately generated shots using FFmpeg (signalstats, colorbalance/colorcorrect/colortemperature, normalize, colormap)?
  Problem. Generated shots of the 'same' scene differ in exposure, white balance and saturation, and there is no colour chart in frame. Conditions. Two or more SDR clips decoded to the same colour space and range; a reference frame you accept as the look. Method. (1) Measure each clip. signalstats exports per-frame metadata keys such as lavfi.signalstats.YMIN and reports for Y, U, V: min, 10th-percentile (LOW), average, 90th-percentile (HIGH), max; SATMIN..SATMAX; HUEMED and HUEAVG; and YDIF/UDIF/VDIF (difference to the previous frame). Use YLOW/YAVG/YHIGH for black point, mid and white point, and SATAVG and HUEAVG for colour (values are in the file's coded range 0-255 as the doc states). The doc describes the filter as aimed at problems of digitised analog video, so use its numbers as relative comparisons only. (2) Correct. colortemperature (1000 to 40000 K, default 6500, mix, pl preserve lightness); colorcorrect (red/blue shift for shadows rl/bl and highlights rh/bh, saturation -3 t...
• articleOverview: when I move a design from a layered source file to a web image or a print PDF, which things travel with the pixels and which stay behind?
  Synthesis supported by reviewed findings: layered files (PSD, ORA, Krita) are working formats whose merged composite is what other tools rely on; each export format carries colour identity differently (PNG chunks with priority, JPEG APP2 ICC segments, AVIF colr box), JPEG has no alpha so transparency must be flattened or carried elsewhere, browsers treat untagged images as sRGB, and print PDF/X needs a declared output condition.
• articleWhat visual differences and artefacts have practitioners reported with ACES 2.0 compared with ACES 1.x (blue gradients, desaturation, colour break-up), and what do ACES working-group members say about causes and remedies?
  Practitioners on ACEScentral reported in 2025 that ACES 2.0 can over-desaturate and show colour break-ups on some saturated sources (one attributing it to the chroma compression), and a relayed working-group answer says the default trades a pleasing look for every image against reaching display corners and invertibility, with LMTs as the remedy. Statements on the Reference Gamut Compression differ: a working-group member says it remains compatible with no recommendation either way, while another participant recommends keeping it disabled because ACES 2 has its own gamut mapper. The ACES docs claim ACES 2 avoids ACES 1 clipping artefacts even with RGC; the reports bound that claim for particular colours rather than refute it. As of a 17 March 2026 TSC summary, a 'technical' LMT for ACES-1-like contrast was being explored and not published.
• articleBefore using a generated world (Marble splat or mesh, HunyuanWorld layers, WonderWorld splat) for previs or as an LED-volume background, what should an agent check, what does the one documented LED-volume use report, and what is unknown?
  Partially verified: the curator re-read none of the cited sources; S25, S20, S9, S15, S16, S21, S5 rest on the producer's pinned reading. The only documented LED-volume use found is a vendor case study (Volinga, Feb 2026): a music video used Marble worlds shown as Gaussian splats in Unreal via the Volinga plugin, with stYpe camera tracking and set extension; the vendor and its customer report time saved and on-set switching, with no data on colour, resolution, latency or artifacts. World Labs' docs add plugin notes for nDisplay and depth of field. WonderWorld's authors say its own results have low density and floaters and suggest it as a coarse prototype to refine. The checks below are proposals synthesised from these statements, not tested procedures.
• articleWhy do AI-generated clips show banding in skies and fog, and when should I use FFmpeg gradfun versus deband versus a 10-bit master?
  Problem. Smooth gradients (sky, fog, walls, vignettes) in generated clips show contour bands, usually worse after delivery encoding. Conditions. 8-bit delivery. BT.709 8-bit coding assigns black 16 and nominal peak 235 (219 steps); 10-bit assigns 64 and 940 (876 steps), so 10-bit has four times the steps over the same range (arithmetic from the table). Open tools quantise float frames to uint8 before encoding (see P-L1-4-03). Method. (1) Decide where the bands enter: at the 8-bit cast/export, or at lossy compression. (2) For a playback-only copy, FFmpeg gradfun=strength[:radius]: strength range .51 to 64 (default 1.2) is both the maximum change per pixel and the flat-region threshold; radius 8 to 32 (default 16); a larger radius gives smoother gradients but protects pixels near detail. The FFmpeg doc says it is designed for playback only and must not be used before lossy compression because compression loses the dither and brings the bands back. (3) deband filter: replaces banded pi...
• articleWhat do open documents define for camera noise and dynamic-range test methods (ISO 15739 public scope, Imatest's documented definitions, EMVA 1288), and what linearity assumptions do they make?
  Dynamic-range figures depend on the method: Imatest reports DR at several scene-referenced SNR thresholds (20, 12, 6, 0 dB), and EMVA 1288 splits into a Linear release and a General release for non-linear cameras or cameras whose preprocessing changes temporal noise; any DR claim must name its method, threshold and encoding handling.
• articleWhich glTF material inputs have no OpenPBR counterpart in the texts read, and which OpenPBR features have no glTF counterpart?
  OpenPBR (1.1.1, still current) and glTF materials don't line up. OpenPBR has no terms for glTF's occlusion texture, alpha cutoff or unlit mode. glTF has no counterpart for OpenPBR's diffuse roughness, subsurface scattering controls or coat darkening. OpenPBR also lets renderers approximate costly features, so some 'loss' is a renderer choice. MaterialX publishes translation graphs that chain OpenPBR -> Standard Surface -> glTF PBR (route inferred from matching input/output names; neither .mtlx file describes the chain in prose; read, not run; amendment CA-AM-0053). The first step carries diffuse roughness, subsurface, coat IOR and coat darkening into Standard Surface, and the second step has no inputs for them, so they are dropped on export to glTF. Coat colour is folded into an attenuation term rather than dropped.
• articleMy application or pipeline does not support ACES 2.0 (or its output looks different from my old ACES 1.x setup): what do vendors and the community document as the safe options?
  As of September 2026 there are three practical routes to ACES 2.0. Hosts on OCIO 2.5 or later (Maya and 3ds Max 2027, per an OCIO developer's post) can load the official ACES 2.0 configs. Blender 5.0 ships its own ACES 1.3 and 2.0 views, including HDR variants. Older hosts can use LUTs baked from an ACES 2.0 config with ociobakelut, which needs a shaper space; one practitioner reported naive bakes crushing low-light detail. In the OCIO-2 ACES configs the color_picking role is sRGB-encoded without tone mapping, so writing review PNGs needs the display transform.
• articleAt DI and delivery, what do AMF/ACES and the IMF Application 2E standard say about reproducing on-set colour intent, and what is not carried?
  AMF lets finishing automatically recreate the on-set or dailies viewing reference, possibly with a different ODT for the better grading display, but holds no timeline data. IMF Application #2E fixes the finished image's colorimetry system (COLOR.1-COLOR.8) and allows optional all-or-none ST 2086 mastering-display items for COLOR.3/5/6/7/8, with nothing assumed when absent; its text names no ACES, timecode or CDL. AAF AS-01 defines tape names and timecode tracks but no CDL/ASC/LUT objects. So none of the documents read states that on-set colour intent itself travels into an IMF package.
• articleDoes Unity Recorder 5.1.7's Movie Recorder tag colour or tonemap video, and what colour space does ProRes output declare?
  The Unity Recorder ProRes encoder hard-codes the Rec.709 colour definition; Rec.2020, PQ and HLG values exist only as commented-out enum entries, so engine ProRes output cannot be tagged for HDR or wide gamut. Whether written files carry tags was not observed.
• articleProperty by property, what do the OpenPBR 1.1.1 specification and the Khronos glTF material READMEs each define for the properties a glTF to OpenPBR conversion must carry?
  OpenPBR v1.1.1 on main (f8d6d947, merged 2026-04-17) contains no glTF text and no retroreflection, occlusion or alpha-cutoff terms, so no source read states a glTF-to-OpenPBR mapping. The glTF retroreflection extension (Release Candidate) says it matches OpenPBR's specular_retroreflectivity, a parameter merged on 2026-02-23 into OpenPBR's dev_1.2 branch, not v1.1.1, which explains the producer-flagged contradiction. glTF dispersion stores 20/V_d (stated as OpenPBR's transform) and emissive strength is a unitless multiplier, while OpenPBR emission_luminance is in nits.
• articleAgentic assistants driving Blender, DaVinci Resolve and After Effects for AI film pre-production and editing (GPT-6 Astra, Sept 2026)
  Creator-reported: statements attributed to the creator(s) come from discovery's reading of auto-caption transcript excerpts; the curator checked the video metadata (title, date, length) and any cited documentation pages, not the spoken claims. Nothing was tested; promotional or sponsored framing applies where stated. Dan Kieft (Higgsfield-sponsored, 2026-09-23) on OpenAI's GPT-6 Astra (launched early Sept 2026 per secondary news listings R4/R5, emphasising computer use; primary OpenAI page not read). Uses: (1) ChatGPT + Blender MCP builds a 3D set (a bar) from a prompt and references; he places cameras for shot angles, renders previs frames, has GPT Image 2.5 make them photoreal, then uses them as Seedance 2.5 references - more control than describing shots in text; Astra also built a web viewer of the set so non-Blender teammates can orbit/walk it. (2) Recreating rooms from photos to plan a studio layout. (3) Thumbnail ideation with own portrait, channel examples and inspiration, a...
• articleFinishing AI-generated video for professional delivery: generate at 720p, upscale, convert 8-bit to 10-bit before grading, and use creative upscalers only for stylised shots
  Two 2026 production accounts (vendor-published) describe the same finishing chain. Primordial Soup (Darren Aronofsky's AI studio) on TIME Studios' YouTube series "On This Day... 1776" (R1): Starlight Precise 2.5 to upscale/refine generated footage across the series; Hyperion 2.5 converted 8-bit generated sources to 10-bit ProRes before a masked ghost grade in DaVinci Resolve because "8-bit GenAI sources do not hold up well under intensive color grading"; Hyperion also reduced visible banding in an extreme close-up; Astra 2 (creative video-to-video upscaler that adds generative detail) used only for an anime-styled episode to sharpen linework. Production mixed SAG actors and performance capture with GenAI animation and conventional edit/sound/colour. Verena Puhm's "Nobody Dies on Mars" (Future Vision XPRIZE 2026 second place, $100,000) (R2): video mostly made with Seedance, "often generated at 720p", then upscaled to 4K with Starlight Precise 2.6 for theatrical presentation; Premiere...
• articleShould I turn the Reference Gamut Compression (RGC) on or off when using ACES 2.0 in Resolve, and what do ACEScentral practitioners say?
  Forum record (2025): an April post expected RGC to be disabled by default in ACES 2; a June post said RGC was not for ACES 2; a reply speaking for the group ('We think') corrected that there is no recommendation for or against RGC in ACES 2, which stays compatible but is expected to be unnecessary in most cases; a December LMT author still applied RGC after the LMT as a stopgap. Answer: optional, not prohibited; no specification text read.
• articleIs the OpenEXR 'acesImageContainerFlag' attribute still a supported thing to write, and did OpenEXR say anything about its name or status?
  OpenEXR maintainers settled the status of the ACES container classes, not the meaning of a mixed signal. PR 2560 (merged 2026-09-05) made acesImageContainerFlag a standard attribute after finding that ImfAcesFile never wrote it. The ACES file classes and exr2aces were deprecated in 3.5.0 (2026-09-22), and the issue about the missing flag was closed on that basis. When a reviewer asked what a reader should do if the ACES flag and a different colorInteropID co-exist, no rule was given.
• articleEditor-integrated generation: making a short animated film entirely inside CapCut PC with Seedance 2.5 (extend to 90 s, localized AI edits)
  Creator-reported: statements attributed to the creator(s) come from discovery's reading of auto-caption transcript excerpts; the curator checked the video metadata (title, date, length) and any cited documentation pages, not the spoken claims. Nothing was tested; promotional or sponsored framing applies where stated. Mikkel Lassalle (CapCut promotional, 2026-08-19). Workflow inside one CapCut PC project: Nano Banana Pro style frame (set resolution/aspect first) -> Seedance 2.5 image/reference-to-video up to 30 s -> multiple reference images to define character, environment and camera language -> "AI Extend" continues the same clip preserving character/environment/lighting/camera; two extensions reach a 90 s maximum -> localized natural-language edits (e.g. remove a person from the frame by selecting the clip as reference and prompting) -> edit and export. CapCut video-tab tools listed: stabilize, enhance quality, denoise, optical flow, AI remove, AI expand, AI remix, eye contact, li...
• articleHow does a working primary colourist describe balancing, shot matching and contrast in a transcribed talk?
  One post-house colourist describes an order of work for matching: balance each shot, match the balanced shots, then apply the look, while noting the steps overlap in practice and that a well-balanced shot responds better to later keys and colour separation. Matching by piling on keys and windows tends to fall apart or look digital; for a hard match she overshoots the correction and dissolves the node's opacity back, and keeps a prepared node that lowers contrast while raising saturation to hold saturation even. Practitioner testimony from one Resolve-centred colourist, with no numeric method.
• articleHow do USWDS colour tokens, contrast rules and Identifier logo guidance constrain graphics for US federal-style sites?
  USWDS asks sites to use its colour tokens rather than custom colours and expresses contrast as a grade difference: 40+ meets WCAG 2.0 AA for large text, 50+ AA (or AAA large text) and 70+ AAA. Its accessibility baseline is WCAG 2.0 AA, it aims at 2.1 AA, and it notes 2.2 is not yet legally required, so the magic-number rule is a 2.0-ratio shortcut. The Identifier must show the parent agency (not a product logo) and should not be used where it would mislead or on test or unofficial sites. Most USWDS code and guidance is CC0, but bundled icons (Apache-2.0) and fonts (SIL OFL 1.1) keep their own licences. Synthesis (producer, supported): an agent should not generate government Identifiers for non-agency work.
• articleWhat are sRGB, Display P3 and an embedded ICC profile, and what happens to an image that carries no colour tag?
  Browsers following CSS Color 4 (CRD, 20 October 2026) treat untagged images as sRGB and treat an image with a valid colour tag as being in that space. Display P3 has DCI-P3 primaries, a D65 white and the sRGB transfer curve. PNG 3 lists four ways to tag colour with precedence cICP, then iCCP, then sRGB, then cHRM+gAMA, and asks viewers to treat unknown-gamma PNGs like untagged images. ICC.1:2022 defines embedded profiles so images carry their colour description between systems; the ICC sRGB page advises not mixing v4 and v2 profiles. Inference (code_derived from the defaults, not a quoted statement): an untagged Display P3 image will be shown as sRGB and look less saturated rather than fail, so read the tag, keep it on export and tag output instead of guessing; a profile describes the numbers rather than changing them (curator agrees as reading of the spec's purpose, not a quoted sentence).
• articleHow do working colourists describe contrast, look development and shot matching decisions, with examples and counterexamples?
  Two public accounts show opposite contrast outcomes for different projects: an interviewed colourist finishes on a soft, film-like contrast curve and says small screens read more contrasty, while a 2016 trade article on Moonlight reports contrast deliberately pushed on set after preproduction tests with the colourist, a three-step look (thick colour from the mid-tones, blue in the blacks, teased highlights) and a different film-stock emulation per chapter. Both place the colourist as translating the cinematographer's intent after early discussion. Shot matching is named only as a duty; no matching method is given. The interviewee's rule of thumb is about 80 hours of grading for a 90-minute film.
• articleIs the OpenEXR prose-versus-flowchart discrepancy (attribute 'present' versus flag 'set') reported in a public ColorInterop tracker issue, and what do the issues say about it?
  The ColorInterop OpenEXR recommendation is internally inconsistent on ACES container detection, and this was still true on main on 2026-10-22. The reading steps say the acesImageContainer attribute takes precedence if it is present; the flowchart asks whether the flag is set. The name also differs from OpenEXR's: OpenEXR's PR 2560 (merged 2026-09-05) added the standard attribute as 'acesImageContainerFlag', not 'acesImageContainer'. Readers should test for the OpenEXR attribute name and decide explicitly whether presence or a true value counts.
• articleWhat do the public licence texts and access pages say about using the ARRI, RED and Blackmagic RAW SDKs (who may use them, redistribution, reverse engineering), without downloading or accepting anything?
  Three different regimes: Blackmagic's BRAW SDK is governed by a separate royalty-free Developer License Agreement (for building compatible software and distributing the API libraries in object code within it), distinct from the fee-based single-system licence shown first on the same page; RED's R3D SDK is royalty-free for internal development, allows redistribution of listed binaries only unmodified inside your program, forbids reverse engineering of R3D formats and carries an indemnity; ARRI's SDKs come through a free two-year Partner Program membership, with some functions possibly charged.
• articleWhich oiiotool switches and config hints control premultiplied versus unassociated alpha at OpenImageIO v3.2.1.2, and what do the docs warn?
  oiiotool premultiplies unassociated-alpha inputs on read by default; --no-autopremult (or the input config oiio:UnassociatedAlpha=1) keeps them unassociated for subsequent inputs. Colour-transform commands accept :unpremult=1 to un-premultiply around the transform, but default to 0, transforming associated values directly. Combine with CA-B398 for the alpha-0/1 edge behaviour.
• articleWhat OCIO and CLF test data are public at a pin, and what does the repository say about their licence?
  OpenColorIO (22dd9c4f) states that all data under tests/data/files (265 files, about 34 MB, including 7 ICC-named test files) is BSD-3-Clause, copyright OpenColorIO contributors, while THIRD-PARTY.md lists SampleICC under the ICC Software License 0.2 without mentioning the test data; the texts read do not say which governs the ICC test files.
• articleWhat does the ACES 2.0 tone scale do, which constants define it, and what changed from the ACES 1.x RRT (glow, red modifier, global desaturation) that sat before its tone curve?
  The ACES 2 docs require a monotonic S-shaped tone scale with mid-grey log-log slope below ACES 1's 1.55, presets for 48/100/108/1000 nits and a Michaelis-Menten-based curve, and tabulate 18% grey output of 10.000 nits at 100 nits and 14.512 at 1000 nits; the ACES 2 CTL sets c_d = 10.013 for 18% grey output; ACES 1.3.1's RRT used glow (0.05/0.08), red modifier (0.82) and 0.96 global desaturation. Licence texts differ by tag: Apache-2.0 at aces-core 069b0bc3, Academy ACES component terms at the 1.3.1 commit fc189808.
• articleWhat are SMPTE ST 2086 mastering-display metadata and CTA-861.3 MaxCLL/MaxFALL, and what can be verified from free public texts?
  SMPTE ST 2086 exists as 2014 and 2018 (stabilized) publications in the SMPTE library, and its text was not read; the free AV1 specification carries the same mastering-display data model (three primaries and white point as 0.16 fixed-point CIE 1931 coordinates, max luminance 24.8 and min luminance 18.14 fixed-point in cd/m2) and defers MaxCLL/MaxFALL definitions to CEA-861.3 Appendix A; FFmpeg stores these as rationals and unsigned cd/m2 values without defining how to measure them.
• articleDoes W3C publish an IMSC 1.3 implementation report with per-renderer pass/fail for ruby, bidi and vertical text, and what do the linked TTML2 and IMSC reports actually show?
  The W3C IMSC 1.3 implementation report adds no test table (all features already covered by TTML2/IMSC 1.2 reports), and per-implementation presentation results for features such as ruby and bidi appear only in the TTML2 implementation report, reported by implementers (e.g. imscJS, TTPE).
• articleWhat are YouTube's current custom thumbnail specs for videos, Shorts and podcasts (sizes, ratios, desktop vs mobile limits, the 4:5 crop)?
  Problem: preparing thumbnail files. Source: YouTube Help 'Add custom thumbnails on YouTube', read 2026-10-23. Source statements: recommended resolution 3840x2160 for videos and 2160x3840 for Shorts (minimum width 640 px for videos, minimum height 640 px for Shorts); JPG or PNG; file limits depend on device: mobile 2 MB for video thumbnails (10 MB for podcasts), desktop 50 MB for video, Shorts and podcast thumbnails; aim for 16:9 for videos, 9:16 for Shorts and 1:1 for podcast playlists. A vertical video with a 16:9 custom thumbnail is replaced by an auto-generated 4:5 thumbnail on the home, explore and subscription pages; the custom one still appears on watch feed, history and non-mobile platforms. Custom Short thumbnails can currently be added only in Studio on a computer and need a verified account; changes may take time to show. This matches the 50 MB desktop limit that the Oct 2025 TV blog said was coming (see P-L4-6-12). Method (inference): design a Short thumbnail at 9:16, che...
• articleWhat new TV features did YouTube announce in Oct 2025 (50 MB thumbnails, AI super-resolution upscaling with opt-out, contextual search, shopping QR), and how does the Help page now match?
  Problem: understanding platform-side changes to how videos appear on TV. Source: YouTube Blog 'New features to help creators shine on TV screens' (Kurt Wilms, 29 Oct 2025), compared with the live thumbnails Help page. Platform statements: channels earning six figures or more from TV screens rose by over 45% (July 2024-June 2025 vs prior year; YouTube-reported); the thumbnail file limit would 'soon' expand from 2 MB to 50 MB so YouTube can serve 4K thumbnails (the Help page now lists a 50 MB desktop limit and 2 MB on mobile, so this has at least partly happened as of 2026-10-23); a new AI-powered feature generates higher resolutions, starting by upscaling videos uploaded below 1080p from SD to HD, with a goal of up to 4K; original files and resolutions are kept, there is an opt-out, and viewers can watch the original resolution, with 'super resolution' labelled under settings; channel pages get immersive previews, and Shows design groups videos; contextual search on TV prioritises a ...
• articleWhich colour-pipeline outputs does Runway's API document for generated video (ProRes, 10-bit Rec.709, HDR, ACEScg EXR) and what does that say about AI plates in a graded timeline?
  Problem. Default AI video is an 8-bit H.264 MP4, which is thin for grading; which vendors deliver more? Conditions. Runway Dev API docs, fetched 2026-10-23; applies to models gen4.5 and aleph2 as stated. Method (documented fields). outputFormat on the generation request: mp4 (default, H.264), prores (.mov; proresProfile 422 Proxy, 422 LT, 422, 422 HQ, 4444, 4444 XQ; default 4444), png_sequence (.zip of PNG frames plus a .wav when there is audio); these stay SDR. sdr_rec709_10bit gives HEVC Main 10 Rec.709 .mp4 for Gen-4.5 and Aleph 2.0 'when a grade needs more precision than 8-bit H.264'. HDR is Gen-4.5 only: hdr10 (HEVC Main 10, BT.2020 + PQ), hlg, hdr_pq_12bit_master (12-bit 4:4:4 BT.2020 PQ .mov), hdr_prores, hdr_png_sequence (16-bit PNG plus colorimetry sidecar), hdr_exr_sequence (half-float OpenEXR, linear BT.2020 light, 1.0 = 100 nits) and two ACEScg EXR options for ACES 1.3 and ACES 2.0. The ACEScg EXRs are scene-referred by inverting the picture through the ACES Output Trans...
• articleAnswers "should colour scopes/transforms apply to EXR depth or data channels?" from primary docs. OpenEXR (R1): channels are named strings (e.g. R, Z, yVelocity); only R, G, B (intensities) and A (opacity; colour channels premultiplied by convention) have predefined interpretations. Data types:...
  Answers "should colour scopes/transforms apply to EXR depth or data channels?" from primary docs. OpenEXR (R1): channels are named strings (e.g. R, Z, yVelocity); only R, G, B (intensities) and A (opacity; colour channels premultiplied by convention) have predefined interpretations. Data types: HALF for regular image data, FLOAT "where the range or precision of 16-bit number is not sufficient (for example, depth channels)", UINT for "discrete per-pixel data such as object identifiers". Compression: lossy DWAA/DWAB quantise DCT components of RGB data; B44/B44A are lossy for HALF; PXR24 keeps HALF and UINT exact but rounds FLOAT to 24 bits (~3e-5 relative error) and "works well for depth buffers"; lossless ZIP/PIZ-type codecs avoid any change - so put data passes (Z, normals, IDs, motion) in lossless or PXR24-compressed parts, not DWA. Data window vs display window: pixel data may extend beyond (overscan) or within the display window. Colour identification: OpenEXR does no colour tran...
• articleHow do I add dither or film grain before the final 8-bit encode so generated gradients survive compression (FFmpeg sws_dither, noise, libplacebo)?
  Problem. Quantising a smooth gradient to 8 bits without dither creates steps; encoders then flatten low-amplitude noise. Conditions. Last step before an 8-bit delivery encode, working from a higher-bit-depth intermediate. Method. (1) FFmpeg's swscale option sws_dither selects the dither used when converting pixel formats: auto (default), none, bayer, ed (error diffusion), a_dither (arithmetic, addition), x_dither (arithmetic, xor; the doc says more random and less apparent patterning than a_dither). (2) The colorspace filter has its own dither option: none or fsb (Floyd-Steinberg). (3) libplacebo dithers whenever necessary by default; its modes include none (the doc warns this may result in visible banding), bayer ordered, blue_noise and floyd_steinberg. (4) Grain: the noise filter adds noise per component with strength 0 to 100 (default 0, so nothing happens unless set) and flags a (averaged temporal, smoother), p (mix with regular pattern), t (temporal: pattern changes between fra...
• articleWhich OpenEXR header attributes carry colour meaning, which one is now preferred, and how should readers and writers treat them?
  Scope: attribute inventory only; for reader behaviour see the OpenEXR reader-rules record C2-B16-B2-01. As an inventory, the five optional colour attributes at OpenEXR v3.5.2 and the chromaticities-superseded note are confirmed in pinned bytes (same bytes as S3 of C2-B16-B2-01).
• articleCoverage note with small facts: 11 more sponsored or self-promotional Mikkel Lassalle uploads (Feb-Mar 2026)
  Creator-reported: statements attributed to the creator(s) come from discovery's reading of auto-caption transcript excerpts; the curator checked the video metadata (title, date, length) and any cited documentation pages, not the spoken claims. Nothing was tested; promotional or sponsored framing applies where stated. Concrete items: Artlist platform tour (2026-03-12, R6) - claims 50M creators; video tools with negative prompts, multiple references, multi-output, four cinematic styles and clip chaining into a long scene; custom voice cloning from about 10 seconds of audio (consent rules apply). Artlist "Big Ad" challenge with a $60,000 prize (R12) - contests as a sponsor marketing tactic. Enter.pro (R2): an "AI development agent" test building a deployable app with payments in about an hour; it recommended Gemini 3 Pro or Claude Sonnet 4.5 for the app's text generation; he configured a freemium plan (5 free shot plans/month, unlimited on Pro). Framia Pro (R1): agent platform with cre...
• articleTool snapshots from mid-2026 sponsored walkthroughs: Meshy texturing options, Lumina canvas planning, Artlist preset apps, Pippit "story series" pitch
  Creator-reported: statements attributed to the creator(s) come from discovery's reading of auto-caption transcript excerpts; the curator checked the video metadata (title, date, length) and any cited documentation pages, not the spoken claims. Nothing was tested; promotional or sponsored framing applies where stated. Meshy (2026-07-30): image-to-3D "quick generate" or agent mode; standard vs "smart topology"; texture step with options to remove baked lighting, generate PBR maps, and texture resolution 2K/4K/8K. Lumina canvas (2026-08-04): describe the story -> auto storyboard of individual shots -> "director's desk" to set framing, composition, camera movement and key shots before generating (claims no queue waiting). Artlist "AI apps" (2026-07-01): 70+ one-click presets in categories (viral, editing tools, camera movement, product, typography, social, collabs) - e.g. product photo -> lifestyle shot or packaging mockup. Pippit Story Studio with Seedance 2.5 (2026-08-20): script/scre...
• articleWhat can AI agents do inside an editing workflow today (trimming, synthetic B-cam angles, motion graphics, LUT grading, sound), and where do they fail?
  Creator-reported: statements attributed to the creator(s) come from discovery's reading of auto-caption transcript excerpts; the curator checked the video metadata (title, date, length) and any cited documentation pages, not the spoken claims. Nothing was tested; promotional or sponsored framing applies where stated. Dan Kieft (2026-09-29, Higgsfield-sponsored) uses a desktop chat agent ("GPT Astra", as he names it) with MCPs for Higgsfield, DaVinci Resolve (paid version) and Blender, plus computer-use control of Premiere Pro/After Effects: (1) trim dead space from transcription, insert editor-note adjustment layers and mark candidate B-cam/C-cam spots - works but slow (about 14 minutes for some trims via screen control; the Resolve MCP is much faster) and needs monitoring; local desktop app needed for large camera files (cloud upload limit 512 MB); (2) synthetic B/C-cam angles: give a photo of the room and the A-cam clip, generate side angles with Seedance 2.5 (plausible shadows an...
• articleHow do creators make AI video look like real camera footage (prompt formula, imperfection, camera behaviour) and pick models for realism?
  Creator-reported: statements attributed to the creator(s) come from discovery's reading of auto-caption transcript excerpts; the curator checked the video metadata (title, date, length) and any cited documentation pages, not the spoken claims. Nothing was tested; promotional or sponsored framing applies where stated. Dan Kieft (2026-10-16, Higgsfield-sponsored): for stills, test the same prompt across several image models because each is trained differently (in his comparisons GPT Image 2.5 "Flare", FLUX 2 Pro, Nano Banana Pro/2.1, Seedream 5.0 and Higgsfield Soul each won some cases; FLUX 3 looked plastic for stills; text rendering failed on Soul 2 and FLUX 2 Pro). His "CTLT" prompt order: Camera (film stock/lens/framing, e.g. 35 mm film, 12 mm fisheye, tilted horizon, slight motion blur), Tone (mood/emotional energy, e.g. "we weren't meant to see this"), subject/action, Lighting (e.g. harsh on-camera flash), Texture (physical surface details); style labels such as disposable-camer...
• articleIn JPEG XL and AVIF HDR stills, which of ICC, CICP/colr, Exif orientation and HDR light-level metadata take precedence, and what do tools document?
  Partially verified: the curator re-read S17, S18, S21, S24; S20 was not re-read by the curator and rests on the producer's pinned reading. JPEG XL keeps everything needed for correct display (including ICC colour and orientation) in the codestream: Exif/XMP boxes do not affect rendering and Exif orientation must be ignored because codestream orientation takes precedence; libjxl's ICC path cannot represent HDR transfer functions exactly. AVIF requires metadata OBUs to match mdcv/clli item properties and says alpha items should omit colr (readers ignore it); libavif also writes CICP into the AV1 sequence header for decoders that ignore colr, and lets a PNG cICP chunk override iCCP.
• articleWhat do TLCI, SSI, CRI and TM-30 measure, and what are their documented limits for choosing lights for camera work?
  Partially verified: the curator re-read S41; S42 was not re-read by the curator and rests on the producer's pinned reading. TLCI-2012 scores a light through a simulated TV camera and display against a reference at the same CCT; its Qa scale is calibrated so a daylight fluorescent tube scores 50, which EBU treats as the watershed between luminaires colourists can and cannot correct acceptably; EBU says CRI was never intended for television.

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