Start with the catalog record
Do not begin with a social-media repost. Reverse-search toward a library, archive, museum or photographer's record. Save the stable item link, collection name, call number or negative number, creator, date range, caption and rights advisory. Record when you accessed it because metadata can be corrected.
The image and its catalog description are separate sources. A caption may have been supplied by the photographer, agency, donor or later cataloger. Repositories often signal uncertainty with brackets, question marks or “unverified data.” Preserve those qualifiers.
Examine the physical and digital object
Check whether the file represents a negative, print, contact sheet, slide, newspaper halftone or copy photograph. A scan may crop an edge that contained handwriting. A reversed negative can swap left and right. Retouching, colorization and compression can erase details.
Look for inscriptions, stamps, agency numbers and neighboring frames. The Library of Congress FSA/OWI collection, for example, preserves many negatives created within a documentary project; related images can clarify sequence and setting. A single selected frame should not stand for every person or condition the project recorded.
Verify time and place
Separate the photograph date from the date printed, published, acquired or digitized. Clothing, vehicles and signs can suggest a range but rarely establish a precise year alone. Compare directory listings, event programs and newspaper coverage.
For location, transcribe signs and street numbers, then check historic maps and addresses. Match building details and street orientation. A current building with similar brickwork is not proof. If evidence supports only a neighborhood, do not publish a doorway-level pin.
Weather, shadows and foliage can assist but are vulnerable to assumption. Use them as corroboration, not the anchor.
Identify people responsibly
Catalog names can be wrong or incomplete. Compare inscriptions, published captions, organizational records and family or community identifications. Explain who supplied an identification and when. Facial resemblance or online comments are not sufficient.
Images can expose private, humiliating or violent moments. Legal access does not remove the need for editorial care. Avoid naming a living person or a child from speculative evidence, and do not use suffering as decorative engagement.
Read framing and caption language
Ask what lies outside the crop, who commissioned the image and what purpose it served. Government documentation, news photography, commercial portraiture and family albums follow different conventions. A caption written under segregation may use demeaning language or flatten individual identity.
Quote only what is necessary, attribute historical language and provide context. If later scholarship corrects the caption, cite both the original record and the correction. Do not edit a historic image in a way that changes evidentiary meaning without disclosure.
Separate access from reuse rights
A public-domain status can depend on creator, publication and jurisdiction. Repository “no known restrictions” language is not identical to a legal guarantee. The U.S. Copyright Office explains that photographers ordinarily own copyright in their photographs unless another arrangement applies.
Review the item-level rights advisory, credit line and reproduction policy. Obtain a high-resolution file through the stated process. A screenshot from a collection site may be poor evidence and may omit required metadata.
Use the photograph in a trip page
Confirm whether the photographed site survives, has moved or is private. Pair the historic view with current conditions only when the viewpoint is safe and lawful. Do not ask travelers to recreate risky roadway or rail images. Describe uncertainty in the caption and alt text.