Archive_Specifications.md

# Archive Specifications

## Scope and Protocol Version

These specifications apply to recordings and drawings created beginning July
15, 2025 unless a metadata row documents a deviation.

The corresponding metadata identifier is:

```text
acquisition_protocol_version = standard-2025-07-15
```

The identifier records the governing protocol. It does not imply that every
published file has identical encoded dimensions, orientation, codec, audio, or
post-processing history.

## Capture Configuration

The documented standard acquisition intent is:

- Capture orientation: Landscape
- Capture resolution class: 2160p UHD (4K)
- Still-image size: 4000 × 3000
- Exposure: Locked
- White balance: Locked

### Capture versus published encoding

Capture orientation and stored pixel orientation are separate properties.
`metadata.csv` fields `width_px`, `height_px`, and `orientation` describe the
published encoded file. Many canonical files are stored as portrait video,
including records that historical evidence identifies as rotations or crops of
landscape sources.

Do not infer a rotation, crop, or transcode solely from dimensions. Such a
transformation should be asserted only when supported by provenance evidence.

## Timing and Calibration Status

The current protocol documentation does not yet provide a complete calibrated
time base for motor-control or physical-trajectory measurement. In particular,
the following may be unknown for a recording unless separately documented:

- original frame-capture interval
- real drawing-session duration
- time-lapse acceleration factor
- source-frame timestamps
- removed pauses or edit decisions
- dropped-frame history
- camera model, lens, and mount geometry
- pixel-to-physical coordinate mapping or homography

`encoded_frame_rate` is playback rate only. It must not be treated as original
drawing-time sampling.

## Drawing Surfaces

### 9 × 12 in

- Strathmore 300 Series Bristol
- Smooth surface
- 100 lb (270 g/m²)
- Acid free

### 11 × 14 in

- Strathmore 300 Series Bristol
- Smooth surface
- 100 lb (270 g/m²)
- Acid free

### 30 × 40 in

- Strathmore 500 Series Illustration Board
- Heavyweight vellum surface
- 20-ply
- White

Other support sizes and materials may appear when identified in the canonical
filename and metadata.

### Open 30 × 40 support review

Fifteen canonical records currently encode `support = Paper` and
`dimensions = 30x40`, while the documented standard surface above is
Illustration Board. This is an unresolved semantic conflict. Downstream users
must not silently relabel those rows, and the archive must not claim the
difference is an acquisition exception until the curator verifies the physical
support or corrects this specification.

## Drawing Instruments and Ink

### Ballpoint

- Pelikan 337 Giant Ballpoint Refill
- Black
- Medium, 1.0 mm
- Document-proof ink conforming to ISO 12757-2

### Fountain pen

- Pilot Custom 823
- Aurora Black fountain pen ink

Additional tools and media are recorded at the individual-record level.

## Audio

Audio presence is a stored-file property, not a required part of the acquisition
protocol. `has_audio` records whether an audio stream exists. It does not
describe the stream's contents or establish redistribution rights for music,
speech, notifications, or other incidental sound.

## Exceptions and Evidence

Known departures from the protocol should be documented in the affected
metadata row. A deviation claim should identify its evidence in `notes` and,
where applicable, provenance fields.

When a property is not documented, it must remain unknown rather than being
reconstructed from visual appearance alone.