Two archives, queried live.
Every record below comes from The Met or Smithsonian Open Access and was filtered on that archive’s own rights field before it reached this page. 12 shown for “Phormidium grande Playfair” — 40 records examined, 1 dropped by the rights gate.
Archives queried 2026-09-01 22:11 UTC · fetched live for this request
isPublicDomain field is true for this object.metadata_usage.access reads CC0 — a waiver, not an expired term.The Metropolitan Museum of Art: HTTP 403 from collectionapi.metmuseum.org. Results from the remaining archive are shown unchanged — nothing is substituted for a source that did not answer.

Phormidium grande Playfair
Artist not stated in the record

Phormidium numarium Playfair
Artist not stated in the record

Phormidium corium var. constrictum Playfair
Artist not stated in the record · 1914

Phormidium corium var. acuminatum Playfair
Artist not stated in the record · 1914

Phormidium tenue var. chlorinum Playfair
Artist not stated in the record · 1912 to 1913

Phormidium scytonematicola N.L. Gardner
Artist not stated in the record · 29 Jan 1915 to 1 Feb 1915

Phormidium durum N.L. Gardner
Artist not stated in the record · 29 Jan 1915

Cylindrospermum stagnale var. australe Playfair
Artist not stated in the record

Plectonema crispatum Playfair
Artist not stated in the record · 1914

Cylindrospermum rectangulare Playfair
Artist not stated in the record

Oscillatoria splendida var. amylacea Playfair
Artist not stated in the record · 1912 to 1913

Oscillatoria simplicissima var. constricta Playfair
Artist not stated in the record · 1916 to 1918
Where these records came from.
Two archives are wired, and only two. Each one is filtered on its own rights field — never on a title match, and never on the presence of an image file.
- The Met Collection API (Open Access)Rights field:
isPublicDomain. HTTP 403 from collectionapi.metmuseum.org. No records from this archive are shown for this query.Unavailable - Smithsonian Open Access API (api.si.edu)Rights field:
content.descriptiveNonRepeating.metadata_usage.access. 82228 matched · 40 examined · 1 dropped by the rights gate. Kept only where metadata_usage.access === "CC0" and an image resource was published.12 shown
These figures describe the pass run at 2026-09-01 22:11 UTC, during this request. A completed pass is kept for 24 hours and replayed for an identical search, which is what keeps repeated queries inside Smithsonian’s 30-requests-per-hour allowance. A pass in which either archive failed to answer is never kept — an outage must not be replayed as though it were a finding about the catalogue.
Wikimedia Commons and the Library of Congress are deliberately not wired. Wikimedia was confirmed, on a live query, to return CC-BY material inside the same result set as genuine public domain works, and filtering it safely has not been designed yet. loc.gov was blocked by bot detection during the source evaluation, so its rights vocabulary has never been observed — and nothing here is built on a field nobody has read.
An image file is a rights claim. It never travels without its field.