Choose index fields people can use

Begin with how users retrieve records

Ask what someone knows at search time: a document date, case number, account number, drawing number, title, report period, location, source box, or a frame reference. Then ask whether that value is present on the item, in a register, in a header, in a punch-code map, or only in an external system. A field without a defined source becomes difficult to trust and maintain.

Also decide what level the field describes. A series title might apply to an entire collection. A reel identifier applies to a roll. A fiche header identifies a sheet. A frame, page, or drawing record needs its own source reference. Mixing these levels into one undifferentiated row makes later retrieval and imports harder.

Use collection, carrier, and item layers

Collection-level fields can include record group, department, system, title, date span, and retention-relevant categories supplied by the customer. Carrier-level fields can describe box, drawer, reel, fiche, jacket, channel, strip, card, polarity, or reduction when known. Item-level fields can include document date, title, case/account/drawing number, source page, report period, or frame position.

Not every project needs every field. For a report-style COM collection, report title, period, fiche sequence, and frame may support retrieval. For aperture cards, drawing number, sheet, revision, and title may be more useful. For a roll of correspondence, date, sender/recipient fields may be sensitive or not suitable for a public index; the approved use case governs the map.

Store where an important value came from

Source provenance makes an index easier to correct. For a field such as revision, possible sources could be “drawing register,” “card label,” “title block OCR,” or “manual review.” This does not weaken the index; it tells later users how the value was derived and where to look if evidence conflicts.

Fictional example — no PII: a card record may show `drawing_number=ME-2047` from `card label`, `revision=B` from `title block`, and `location=Plant 3` from `drawing register`. A stable card ID links each value to the captured source image rather than hiding all evidence in one text string.

Document the fields before delivery

A data dictionary should list source field, normalized field, target field, data type, allowed values, date format, repeatability, required status, and transformation rule. This is the bridge between inventory language and a repository’s content types, templates, document classes, or object properties.

National Microfilm can review customer-defined fields, file relationships, OCR status, and destination needs as part of a project scope. The final map follows the approved retrieval and import workflow; it is not assumed from a generic microform template.

Common questions