046

blvh:slot:046

sampling_operation; slot=046; candidate_set=historical; subgroup=technology_modernity; target_period=1870-1899; query_pool=railway; factory; telegraph; steamship; industrial machinery; mask_rule=record; do not use as truth criterion; book_cap=max 2 selected images per book; selection_method=SigLIP2 semantic retrieval + diversity review; required_provenance=fname, record_id, query_text, rank, similarity, model, image_type, date_raw; status=TO_SELECT; sampling_version=blvh-0.2. observation_status=machine_selection_plan; NEVER promote the semantic query to a factual subject label.