{ "model": { "rank": 6330, "code": "thing-q178051", "model_id": "vr.tr.portable-network-graphics", "name": "Portable Network Graphics", "purpose": "Enable an AI agent to recognise a Portable Network Graphics artifact, assess its interpretability and integrity, and choose transformations that preserve the image properties required by its intended use.", "family": "Thing Registry", "category": "Information and virtual systems", "status": "research-draft", "kind": "thing", "plane": "INF", "domain": "INF.KNW", "industry": "", "version": "", "url": "/models/thing/q178051/", "tier": 2, "score": 61, "payload": { "layer": "wikidata", "aliases": [], "aliasCount": 0, "merged": 0, "knownIn": 61, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": null, "source": { "dataset": "wikidata", "item": "Q178051", "url": "https://www.wikidata.org/wiki/Q178051", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-07T13:51:00Z", "providers": [ "Codex", "Grok" ], "missingProviders": [], "pass": 2, "cost": { "grok": { "usd": 0.00410856, "turns": 1, "seconds": 57.3, "error": null }, "codex": { "seconds": 76.6, "error": "Reading additional input from stdin...\nOpenAI Codex v0.153.3\n--------\nworkdir: R:\\02_PROJECTS\\02_Meta_Models_Platforms\\Ver.cy\\current\\thing-registry-backlog\nmodel: gpt-6-astra\nprovider: openai\napproval: never\nsandbox: read-only\nreasoning effort: none\nreasoning summaries: none\nsession id: 01a07c21-c937-7952-9045-82f8c5811866\n--------\nuser\nYou are drafting a Vercy meta-model for one registered thing. Answer as JSON only, no prose around it.\n\nThing: Portable Network Graphics\nRegistry id: vr.tr.portable-network-graphics\nPlane / domain: INF / INF.KNW\nRegistry definition: (none recorded)\nNames folde" } } }, "metaModel": { "id": "THING-Q178051", "registryId": "vr.tr.portable-network-graphics", "name": "Portable Network Graphics", "version": "0.1.0-research.1", "entryKind": "thing", "family": "Thing Registry", "domain": [ "INF.KNW" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q178051/", "model": { "registry_id": "vr.tr.portable-network-graphics", "name": "Portable Network Graphics", "purpose": "Enable an AI agent to recognise a Portable Network Graphics artifact, assess its interpretability and integrity, and choose transformations that preserve the image properties required by its intended use.", "definition": "Portable Network Graphics (PNG) is a lossless raster image file format specified by ISO/IEC 15948 and W3C Recommendation, using DEFLATE compression and an extensible chunk structure to store paletted, grayscale, or truecolor samples with optional alpha.", "scope_statement": "This model owns PNG-specific recognition, encoded image properties, rendering interpretation, optional animation, conformance evidence and transformation constraints for registry entry vr.tr.portable-network-graphics.", "in_scope": [ "PNG datastream identity, chunk inventory and structural validity", "Raster dimensions, sample representation, palette and transparency", "Colour interpretation and embedded image metadata", "Static-image or animated-PNG behaviour and fallback rendering", "Decoder compatibility, resource requirements and preservation-aware transformations" ], "out_of_scope": [ "The depicted subject, its meaning and domain-specific interpretation", "General file storage, transport, access permissions and backup management", "Image copyright, licensing and ownership adjudication", "Internal implementation and maintenance of image-processing software", "Vector artwork, layered editing projects and other image-format specifications" ], "distinguishing_features": [ "Check for the eight-byte signature 89 50 4E 47 0D 0A 1A 0A and a parseable PNG chunk stream; a filename extension alone is insufficient. Reference: [W3C PNG specification](https://www.w3.org/TR/png-3/).", "Confirm an IHDR-led structure containing IDAT image data and ending with IEND; distinguish PNG from JPEG, GIF and WebP by parsed structure. Reference: [W3C PNG specification](https://www.w3.org/TR/png-3/).", "Identify grayscale, truecolour or indexed samples and their transparency representation; transparency alone does not identify PNG. Reference: [W3C PNG specification](https://www.w3.org/TR/png-3/).", "Inspect animation-control and frame chunks before declaring the artifact static: PNG can carry frame-based animation. Reference: [W3C PNG specification](https://www.w3.org/TR/png-3/).", "Treat PNG's lossless compression as a property of its encoded samples, not proof that earlier image creation or conversion preserved an original. Reference: [W3C PNG specification](https://www.w3.org/TR/png-3/)." ], "characteristics": [ { "name": "PNG recognition state", "kind": "state", "unit_or_values": "uninspected | signature-match | structurally-recognised | conflicting-evidence | rejected", "why_it_matters": "Separates a tentative identification from evidence sufficient to select a PNG parser." }, { "name": "Canvas dimensions", "kind": "measurement", "unit_or_values": "width and height in pixels", "why_it_matters": "Determines suitability for the intended placement and contributes to decoding resource estimates." }, { "name": "Sample representation", "kind": "category", "unit_or_values": "recorded IHDR colour type and bit depth, with combination-validity assessment", "why_it_matters": "Constrains decoding, palette interpretation and conversions that can preserve sample precision." }, { "name": "Transparency representation", "kind": "category", "unit_or_values": "none | transparent-sample value | palette alpha | per-pixel alpha | invalid | unknown", "why_it_matters": "Determines compositing requirements and what flattening or palette conversion would change." }, { "name": "Colour interpretation evidence", "kind": "state", "unit_or_values": "absent | present-unassessed | coherent | conflicting | unsupported; retain relevant chunk evidence", "why_it_matters": "Prevents an agent from treating assumed colour interpretation as an embedded declaration." }, { "name": "Chunk validation state", "kind": "state", "unit_or_values": "unchecked | passed | failed | incomplete, with chunk offsets and diagnostics", "why_it_matters": "Supports decisions to accept, investigate or reject the artifact without confusing readability with conformance." }, { "name": "Animation interpretation", "kind": "category", "unit_or_values": "static | valid-animation | malformed-animation | unresolved", "why_it_matters": "Determines whether frame timing, compositing and playback must be preserved." }, { "name": "Animation extent", "kind": "measurement", "unit_or_values": "declared and decoded frame counts; frame delays in seconds; finite or unbounded playback", "why_it_matters": "Supports playback verification, preview selection and resource budgeting." }, { "name": "Decode resource estimate", "kind": "measurement", "unit_or_values": "estimated peak bytes and processed pixels, with decoder assumptions", "why_it_matters": "Allows inspection to be bounded before allocating image or animation buffers." }, { "name": "Target decoder compatibility", "kind": "relation", "unit_or_values": "decoder and version linked to tested PNG features and observed outcomes", "why_it_matters": "Makes compatibility claims specific to the software that will actually consume the artifact." }, { "name": "Required preservation level", "kind": "category", "unit_or_values": "byte identity | decoded samples | colour-managed appearance | animation behaviour | task-defined combination", "why_it_matters": "Defines the evidence needed before accepting an optimisation or conversion." } ], "affordances": [ "Identify and validate a candidate PNG while retaining precise failure evidence.", "Decode or preview the image under recorded colour, transparency and resource assumptions.", "Inspect animation frames, playback controls and the static fallback.", "Recompress or reorganise eligible chunks against explicit preservation requirements.", "Resize, recolour, flatten transparency or convert formats while recording intended losses.", "Inspect, retain or remove embedded metadata according to the artifact's intended use." ] }, "sources": [ { "id": "iso-15948", "title": "ISO/IEC 15948:2004 Information technology - Computer graphics and image processing - Portable Network Graphics (PNG): Functional specification", "url": "https://www.iso.org/standard/29581.html", "what_it_supports": "Normative identity of PNG as an ISO/IEC International Standard; functional specification of the file format.", "url_status": "blocked" }, { "id": "w3c-png", "title": "Portable Network Graphics (PNG) Specification (Third Edition)", "url": "https://www.w3.org/TR/png/", "what_it_supports": "Current W3C Recommendation covering chunks, colour types, interlacing, compression, and colour management.", "url_status": "live" }, { "id": "rfc-2083", "title": "RFC 2083: PNG (Portable Network Graphics) Specification Version 1.0", "url": "https://www.rfc-editor.org/rfc/rfc2083", "what_it_supports": "Original IETF publication of PNG 1.0; historical source of the format definition.", "url_status": "live" }, { "id": "wikidata-q178051", "title": "Portable Network Graphics (Q178051)", "url": "https://www.wikidata.org/wiki/Q178051", "what_it_supports": "Stable identifier and aliases used in public catalogues.", "url_status": "live" } ], "structure": { "bundles": [ { "id": "datastream-recognition-and-conformance", "name": "Datastream recognition and conformance", "description": "Evidence that the candidate is PNG and that its encoded structure is acceptable.", "rationale": "An agent needs to distinguish identification, structural validity and decoder tolerance before operating on the image.", "layers": [ { "id": "signature-and-chunk-layout", "name": "Signature and chunk layout", "description": "Observable framing of the candidate PNG stream.", "findings": [ { "id": "png-identity-evidence", "name": "PNG identity evidence", "description": "Record signature results, chunk boundaries and discrepancies with declared file type.", "questions": [ { "text": "Do the bytes support PNG identification, and where does the candidate datastream begin and end?", "kind": "definition", "id": "png-identity-evidence-q01" }, { "text": "Are chunk lengths, required chunks and ordering valid under the selected PNG specification?", "kind": "boundary", "id": "png-identity-evidence-q02" } ] } ] }, { "id": "validation-and-extension-handling", "name": "Validation and extension handling", "description": "Assessment of corruption, unsupported features and chunk interpretation.", "findings": [ { "id": "chunk-and-decode-diagnostics", "name": "Chunk and decode diagnostics", "description": "Keep chunk-check results separate from successful decoding and record the treatment of unfamiliar chunks.", "questions": [ { "text": "Which CRC, ordering or image-data checks passed, failed or remained unperformed?", "kind": "measurement", "id": "chunk-and-decode-diagnostics-q01" }, { "text": "Which unknown chunks require rejection, permit ignoring or constrain copying after an edit?", "kind": "action", "id": "chunk-and-decode-diagnostics-q02" }, { "text": "Which validator, version and specification baseline produced this assessment?", "kind": "provenance", "id": "chunk-and-decode-diagnostics-q03" } ] } ] } ] }, { "id": "raster-samples-and-transparency", "name": "Raster samples and transparency", "description": "The canvas and encoded samples that determine image reconstruction.", "rationale": "PNG transformations depend on precision, palette interpretation and transparency rather than dimensions alone.", "layers": [ { "id": "canvas-and-sample-layout", "name": "Canvas and sample layout", "description": "Dimensions, colour type, bit depth and palette interpretation.", "findings": [ { "id": "encoded-raster-representation", "name": "Encoded raster representation", "description": "Record the declared sample layout and whether decoded data agrees with it.", "questions": [ { "text": "What are the canvas dimensions, colour type, bit depth and interlace method?", "kind": "measurement", "id": "encoded-raster-representation-q01" }, { "text": "Is the representation valid, including any required palette and decoded palette-index bounds?", "kind": "boundary", "id": "encoded-raster-representation-q02" } ] } ] }, { "id": "alpha-and-background-compositing", "name": "Alpha and background compositing", "description": "Transparency evidence and the assumptions used when displaying or flattening it.", "findings": [ { "id": "transparency-preservation", "name": "Transparency preservation", "description": "Record encoded transparency separately from the background chosen by a renderer or transformation.", "questions": [ { "text": "How is transparency represented, and does decoding reveal opaque, transparent or partially transparent pixels?", "kind": "measurement", "id": "transparency-preservation-q01" }, { "text": "What background and compositing interpretation are required before flattening transparency?", "kind": "action", "id": "transparency-preservation-q02" }, { "text": "Must colour samples beneath fully transparent pixels survive the proposed operation?", "kind": "boundary", "id": "transparency-preservation-q03" } ] } ] } ] }, { "id": "colour-and-embedded-context", "name": "Colour and embedded context", "description": "Embedded information that affects appearance or contextual interpretation.", "rationale": "Preserving pixel values alone may not preserve appearance or the contextual information required by downstream use.", "layers": [ { "id": "colour-interpretation", "name": "Colour interpretation", "description": "Declared colour information, conflicts and renderer assumptions.", "findings": [ { "id": "colour-evidence-and-rendering-policy", "name": "Colour evidence and rendering policy", "description": "Record relevant colour chunks and the interpretation selected for the intended renderer.", "questions": [ { "text": "Which profile, transfer-function, chromaticity or HDR-related declarations are present and readable?", "kind": "measurement", "id": "colour-evidence-and-rendering-policy-q01" }, { "text": "How does the selected specification resolve overlapping declarations, and what assumptions fill missing information?", "kind": "boundary", "id": "colour-evidence-and-rendering-policy-q02" }, { "text": "Which declarations does the target renderer actually honour?", "kind": "measurement", "id": "colour-evidence-and-rendering-policy-q03" } ] } ] }, { "id": "metadata-meaning-and-retention", "name": "Metadata meaning and retention", "description": "Embedded contextual information and its relevance to an operation.", "findings": [ { "id": "embedded-context-inventory", "name": "Embedded context inventory", "description": "Inventory textual, physical-dimension, Exif and other contextual chunks without treating their contents as verified facts.", "questions": [ { "text": "What contextual metadata is present, and which statements have independent provenance evidence?", "kind": "provenance", "id": "embedded-context-inventory-q01" }, { "text": "Which metadata must be retained, updated or removed for the intended transformation and destination?", "kind": "action", "id": "embedded-context-inventory-q02" } ] } ] } ] }, { "id": "animation-and-static-fallback", "name": "Animation and static fallback", "description": "Optional animated-PNG structure, playback and default-image behaviour.", "rationale": "A still preview can conceal frame content or timing that an agent must preserve or deliberately discard.", "layers": [ { "id": "frame-structure-and-fallback", "name": "Frame structure and fallback", "description": "Animation identification, frame organisation and default-image relationship.", "findings": [ { "id": "animation-structure-assessment", "name": "Animation structure assessment", "description": "Record declared animation controls, decoded frames and the image available to a static-only consumer.", "questions": [ { "text": "Do animation-control and frame chunks form a valid sequence with consistent frame counts and canvas bounds?", "kind": "boundary", "id": "animation-structure-assessment-q01" }, { "text": "What default image appears without animation support, and does it participate in the animation?", "kind": "definition", "id": "animation-structure-assessment-q02" } ] } ] }, { "id": "timing-and-frame-compositing", "name": "Timing and frame compositing", "description": "Playback timing, repetition and reconstruction of displayed frames.", "findings": [ { "id": "playback-preservation-contract", "name": "Playback preservation contract", "description": "Record frame delays, blend and disposal controls, loop intent and observed playback.", "questions": [ { "text": "What delays, repeat count, frame rectangles, blend operations and disposal operations govern playback?", "kind": "measurement", "id": "playback-preservation-contract-q01" }, { "text": "Which displayed frame, timestamp or default image should a requested still-image extraction represent?", "kind": "action", "id": "playback-preservation-contract-q02" }, { "text": "Does the target player reproduce the required timing and compositing behaviour?", "kind": "measurement", "id": "playback-preservation-contract-q03" } ] } ] } ] }, { "id": "bounded-processing-and-transformation", "name": "Bounded processing and transformation", "description": "Conditions for decoding, editing and delivering the PNG successfully.", "rationale": "An agent must connect PNG properties to resource limits and explicit preservation outcomes before selecting an operation.", "layers": [ { "id": "decode-feasibility", "name": "Decode feasibility", "description": "Resource estimates and compatibility with the intended processing environment.", "findings": [ { "id": "bounded-decode-plan", "name": "Bounded decode plan", "description": "Assess the work implied by dimensions, samples, compressed ancillary data and optional animation.", "questions": [ { "text": "What memory and processing estimates follow from the canvas, sample layout, frame sequence and metadata payloads?", "kind": "measurement", "id": "bounded-decode-plan-q01" }, { "text": "Which limits and decoder capabilities determine whether inspection can proceed, stop early or require another tool?", "kind": "action", "id": "bounded-decode-plan-q02" } ] } ] }, { "id": "edit-permission-and-result-equivalence", "name": "Edit permission and result equivalence", "description": "The intended change and evidence that its required image properties survive.", "findings": [ { "id": "png-transformation-contract", "name": "PNG transformation contract", "description": "Specify allowed changes and compare the result at the preservation level required by the task.", "questions": [ { "text": "Must this operation preserve original bytes, decoded samples, rendered appearance, metadata or animation behaviour?", "kind": "boundary", "id": "png-transformation-contract-q01" }, { "text": "Which recompression, palette, precision, resizing or format-conversion changes are authorised by that requirement?", "kind": "action", "id": "png-transformation-contract-q02" }, { "text": "What validation and before-and-after comparison demonstrate that the output satisfies the contract?", "kind": "measurement", "id": "png-transformation-contract-q03" } ] } ] } ] }, { "id": "evidence-and-external-alignment", "name": "Evidence and external alignment", "description": "What the world already says about this thing, gathered so the model can be checked against it.", "rationale": "A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.", "layers": [ { "id": "reported-evidence", "name": "Reported evidence", "description": "Findings from the breadth pass, kept separate from the structural claims.", "findings": [ { "id": "evidence-kinds", "name": "Kinds and varieties", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "PNG-8 (indexed-color, up to 256 palette entries, optional tRNS transparency)", "PNG-24 (truecolor RGB, 8 bits per sample, no alpha)", "PNG-32 (truecolor RGB plus alpha, 8 bits per sample)", "PNG-48 / PNG-64 (16-bit-per-sample truecolor, without or with alpha)", "Grayscale PNG (1-16 bits per sample, optional alpha or tRNS)", "Animated PNG (APNG, unofficial Mozilla/Apple extension with acTL/fcTL/fdAT chunks)", "Interlaced PNG (Adam7 pass order)", "PNG with ancillary metadata (gAMA, cHRM, iCCP, sRGB, eXIf, pHYs, tEXt/iTXt/zTXt)" ], "questions": [ { "id": "evidence-kinds-q01", "text": "Which of these kinds and varieties hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-identifiers", "name": "Identifiers and schemes", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ { "scheme": "Wikidata", "value_or_pattern": "Q178051", "note": "Item for the PNG file format." }, { "scheme": "ISO/IEC", "value_or_pattern": "ISO/IEC 15948:2004", "note": "International Standard for PNG functional specification." }, { "scheme": "IANA media type", "value_or_pattern": "image/png", "note": "Registered MIME type." }, { "scheme": "Filename extension", "value_or_pattern": ".png", "note": "Conventional extension; case-insensitive on most platforms." }, { "scheme": "Magic number", "value_or_pattern": "89 50 4E 47 0D 0A 1A 0A", "note": "8-byte PNG signature at start of file." }, { "scheme": "PRONOM", "value_or_pattern": "fmt/11, fmt/12, fmt/13, fmt/935", "note": "The National Archives UK format identifiers for PNG 1.0, 1.1, 1.2, and Extended PNG." }, { "scheme": "UTI", "value_or_pattern": "public.png", "note": "Apple Uniform Type Identifier." } ], "questions": [ { "id": "evidence-identifiers-q01", "text": "Which of these identifiers and schemes hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-standards-and-regulation", "name": "Standards and regulation", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "ISO/IEC 15948:2004 - ISO/IEC JTC 1/SC 24 (functional specification of PNG)", "W3C Recommendation: Portable Network Graphics (PNG) Specification (Third Edition), 2025 - World Wide Web Consortium", "RFC 2083 (informational) - IETF (PNG 1.0, 1997)", "W3C Recommendation PNG Specification (Second Edition), 2003 - aligned with ISO/IEC 15948:2003", "IANA media type registration image/png - Internet Assigned Numbers Authority", "APNG is not in ISO/IEC 15948; it is a de-facto extension (Mozilla, later Apple) using private/unofficial chunks" ], "questions": [ { "id": "evidence-standards-and-regulation-q01", "text": "Which of these standards and regulation hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-real-world-use", "name": "Real-world use", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "Web and UI graphics where lossless fidelity and alpha transparency are required (icons, diagrams, screenshots, overlays).", "Digital preservation and scientific imaging when lossy JPEG artefacts are unacceptable.", "Game and app asset pipelines for sprites and UI with alpha; often converted to GPU-native formats at runtime.", "Screenshot and document export default on many operating systems (Windows Snipping Tool, macOS, browsers).", "Print and prepress less common than TIFF/PDF; PNG is used for web-to-print proofs and some desktop publishing.", "APNG used for short lossless animations (stickers, UI loaders) as a GIF replacement where supported." ], "questions": [ { "id": "evidence-real-world-use-q01", "text": "Which of these real-world use hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-measurements", "name": "Typical measurements", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ { "quantity": "Bit depth per sample", "typical_range": "1, 2, 4, 8, or 16", "unit": "bits" }, { "quantity": "Colour type", "typical_range": "0 grayscale, 2 RGB, 3 indexed, 4 grayscale+alpha, 6 RGBA", "unit": "enum (IHDR colour type)" }, { "quantity": "Image dimensions", "typical_range": "1-1 000 000+ pixels per axis in the spec; practical web assets often 16-4096 px", "unit": "pixels" }, { "quantity": "File size (web icon / UI)", "typical_range": "about 1-500", "unit": "KiB" }, { "quantity": "File size (screenshot / photo-like lossless)", "typical_range": "about 0.2-50", "unit": "MiB" }, { "quantity": "Compression method", "typical_range": "0 only (DEFLATE/zlib, as of PNG 1.2 / ISO 15948)", "unit": "IHDR compression method code" }, { "quantity": "Gamma (gAMA)", "typical_range": "typically 45455 representing 1/2.2, or omitted in favour of sRGB/iCCP", "unit": "stored as gamma × 100000" } ], "questions": [ { "id": "evidence-measurements-q01", "text": "Which of these typical measurements hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-failure-modes-and-hazards", "name": "Failure modes and hazards", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "Decompression bombs: tiny compressed files expand to huge bitmaps and exhaust memory (historical browser/libpng CVEs).", "Chunk-length and CRC errors: truncated or corrupted files fail to decode; some decoders abort, others skip ancillary chunks.", "Incorrect colour management: ignoring gAMA/cHRM/iCCP/sRGB yields washed-out or oversaturated display versus sRGB-assuming viewers.", "tRNS vs full alpha mismatch: indexed/grayscale transparency handled differently across editors, causing unexpected opaque regions.", "APNG treated as still PNG by decoders that ignore acTL/fcTL/fdAT, showing only the default image.", "CgBI (iOS Xcode) and other private chunks produce files that are not ISO PNG and fail in standard decoders.", "No native CMYK or 32-bit float HDR in the core format; converting from those spaces loses or mis-maps colour.", "Lossless but inefficient for photographic content versus JPEG/WebP/AVIF; large files strain bandwidth and caches.", "Security: historically, libpng integer overflows and overruns in ancillary chunk parsers (eXIf, iCCP, tEXt)." ], "questions": [ { "id": "evidence-failure-modes-and-hazards-q01", "text": "Which of these failure modes and hazards hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-regional-variation", "name": "Regional variation", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ "Filename extension is universally .png; no significant regional naming split.", "Some East Asian software historically labelled 8-bit indexed PNG as \"PNG-8\" following Adobe/Macromedia web-export jargon rather than the ISO colour-type numbers.", "Apple platforms historically emitted CgBI-optimized PNG from Xcode that is not portable ISO PNG; Android and web stacks expect standard PNG.", "Animated PNG support is uneven: Firefox, Chrome, Safari support APNG; some professional imaging tools still treat PNG as still-only.", "PRONOM and national archives distinguish PNG 1.0/1.1/1.2 versions that web developers rarely name." ], "questions": [ { "id": "evidence-regional-variation-q01", "text": "Which of these regional variation hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] }, { "id": "evidence-neighbours", "name": "Neighbouring kinds and how to tell them apart", "description": "Reported by the breadth pass; each item needs checking against its source before it becomes normative.", "evidence": [ { "name": "GIF", "difference": "GIF is indexed-color (≤256 colours) with optional animation and a patent-era LZW history; PNG is lossless for 24/32-bit colour and alpha. Animation in PNG is APNG, not GIF's graphic-control extensions. Test: 8-byte signature 89 50 4E 47… versus GIF87a/GIF89a." }, { "name": "JPEG / JFIF", "difference": "JPEG is typically lossy DCT for photographs and has no native alpha; PNG is lossless DEFLATE. Test: JPEG SOI FF D8 vs PNG signature; also JPEG artefacts vs exact pixel reconstruction." }, { "name": "WebP (lossless and lossy)", "difference": "WebP can be lossy or lossless and supports animation and alpha; container is RIFF. Test: RIFF….WEBP versus PNG signature. WebP lossless often smaller than PNG for photos; PNG remains the interchange default." }, { "name": "AVIF", "difference": "AVIF is HEIF/AV1, usually lossy with optional lossless, HDR-capable; PNG is a simple chunked bitmap. Test: ftyp/avif brands versus PNG signature." }, { "name": "TIFF", "difference": "TIFF is a tagged container with many compressions (including uncompressed, LZW, JPEG) and CMYK/multi-page; PNG is a single-image web/interchange format with a fixed DEFLATE method. Test: II*/MM* TIFF header versus PNG signature." }, { "name": "MNG / JNG", "difference": "MNG was the official PNG-group animation/multiple-image format and JNG a JPEG-in-PNG-wrapper; both failed to gain web adoption. APNG is a PNG-compatible extension. Test: MNG signature 8A 4D 4E 47… versus PNG 89 50 4E 47…." }, { "name": "BMP / Windows bitmap", "difference": "BMP is typically uncompressed raster with optional alpha in later DIB variants; PNG is compressed and portable. Test: BM magic versus PNG signature." } ], "questions": [ { "id": "evidence-neighbours-q01", "text": "Which of these neighbouring kinds and how to tell them apart hold for the sense of Portable Network Graphics this model covers, and on what evidence?", "kind": "provenance" } ] } ] } ] } ] }, "openQuestions": [ "Does the existing Vercy catalogue already contain an authoritative PNG or image-format model that this registry entry should reference or specialise?", "Should this registry entry represent PNG as a format-level concept, individual PNG artifacts, or a format model with an explicit artifact-assessment component?", "Which PNG specification edition and extension set should define the publication's conformance baseline?", "Which target decoders must be tested for animation, colour declarations, HDR interpretation and malformed-input handling?", "What task-specific resource limits and equivalence criteria should govern optimisation, metadata removal and conversion?" ], "statistics": { "bundles": 6, "layers": 11, "findings": 18, "questions": 33 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "discipline or field of knowledge", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a Portable Network Graphics, record what state it is in, and decide what may be done with it.", "whatItIs": "Enable an AI agent to recognise a Portable Network Graphics artifact, assess its interpretability and integrity, and choose transformations that preserve the image properties required by its intended use.", "characteristics": { "substance": "information", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "read and interpreted" ], "distinguishingFeatures": [ "Described in 61 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a Portable Network Graphics, and on what evidence are they told apart?" ], "whatItIsMadeOf": "content that has to be carried by something else", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "read it and act on what it says" ], "howItIsRecognised": [], "relatedModels": [], "standing": "Described in 61 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one Portable Network Graphics from another, and a Portable Network Graphics from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a Portable Network Graphics sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a Portable Network Graphics from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a Portable Network Graphics passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a Portable Network Graphics between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a Portable Network Graphics, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a Portable Network Graphics is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "content-and-access", "name": "Content, encoding and access", "description": "What a Portable Network Graphics says, how it is encoded and who may read it.", "rationale": "An informational thing carries content that can be copied, versioned and withheld, none of which its physical carrier explains.", "layers": [ { "id": "content-and-encoding", "name": "Content and encoding", "description": "The content itself, its format and its language.", "findings": [ { "id": "content-and-format", "name": "Content, format and language", "description": "What a Portable Network Graphics contains and in what form it is held.", "questions": [ { "id": "content-and-format-q01", "text": "What identifies and describes the content of a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "content-and-format-q02", "text": "Who or what asserted this about the content of a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "content-and-format-q03", "text": "What may an agent decide or do once the content of a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "access-and-rights", "name": "Access, rights and retention", "description": "Who may read, copy or change it, and for how long it is kept.", "findings": [ { "id": "access-rules", "name": "Access rules and retention", "description": "The permissions attached to a Portable Network Graphics and the period it survives.", "questions": [ { "id": "access-rules-q01", "text": "What identifies and describes access to a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "access-rules-q02", "text": "Who or what asserted this about access to a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "access-rules-q03", "text": "What may an agent decide or do once access to a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "subject-and-method", "name": "Subject matter and method", "description": "What Portable Network Graphics studies and how it establishes anything.", "rationale": "A field is identified by its questions and its methods, and those are what distinguish it from the fields next to it.", "layers": [ { "id": "subject", "name": "Subject matter", "description": "The questions it takes as its own.", "findings": [ { "id": "subject-record", "name": "Questions and objects of study", "description": "What it is about, stated so a neighbouring field can be told apart.", "questions": [ { "id": "subject-record-q01", "text": "What questions and objects does Portable Network Graphics take as its own?", "kind": "definition" }, { "id": "subject-record-q02", "text": "Which questions does it share with a neighbouring field, and who claims them?", "kind": "boundary" } ] } ] }, { "id": "method", "name": "Method and evidence", "description": "How claims are established and what counts as evidence.", "findings": [ { "id": "method-record", "name": "Methods and standards of evidence", "description": "The methods used and what they are taken to establish.", "questions": [ { "id": "method-record-q01", "text": "By what methods does Portable Network Graphics establish claims, and what counts as sufficient evidence?", "kind": "provenance" }, { "id": "method-record-q02", "text": "What kind of claim can this field not settle, and where should an agent look instead?", "kind": "action" } ] } ] } ] }, { "id": "institutions-and-classification", "name": "Institutions and classification", "description": "Where Portable Network Graphics is practised and how catalogues place it.", "rationale": "The institutional footprint is the evidence that a field exists as a field rather than as a topic.", "layers": [ { "id": "institutions", "name": "Institutional markers", "description": "Societies, journals, degrees and departments.", "findings": [ { "id": "institution-record", "name": "Bodies and venues", "description": "Where the field organises itself.", "questions": [ { "id": "institution-record-q01", "text": "Which societies, journals or degrees mark Portable Network Graphics as an established field?", "kind": "provenance" }, { "id": "institution-record-q02", "text": "What would show that it is emerging or dissolving rather than established?", "kind": "boundary" } ] } ] }, { "id": "classification", "name": "Classification schemes", "description": "Where library and research classifications put it.", "findings": [ { "id": "classification-record", "name": "Codes and their disagreements", "description": "The classification codes that place it, and where they differ.", "questions": [ { "id": "classification-record-q01", "text": "Which classification schemes place Portable Network Graphics, under what codes?", "kind": "definition" }, { "id": "classification-record-q02", "text": "Where do those schemes disagree about its scope?", "kind": "boundary" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a Portable Network Graphics came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a Portable Network Graphics and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a Portable Network Graphics is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a Portable Network Graphics, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a Portable Network Graphics, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a Portable Network Graphics is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 6, "layers": 12, "findings": 14, "questions": 38 } } } }