Indelible Sepia

Indelible Sepia is a certified ink formulation of the eleventh chromatic grade, approved for the permanent inscription of surfaces whose eventual disposal has not been determined. It is chemically distinct from Indelible Grey — which the Grey Basin Transcripts confine to stone — in that Indelible Sepia binds to parchment, linen, bone, and to at least one recorded instance of a rendered fat. Its designation derives not from colour, which is a matter of some contention, but from the octopus of the Middle Vats, whose suspension constitutes its principal body.

Unlike the formulations subject to Indelible Spring, Indelible Sepia does not return to fluid under any observed condition. The Librarians have confirmed this in writing on four occasions, twice at the request of the Office of Material Coherence.

Composition and the Middle Vats

The ink is drawn from the Suspended Cephalopod Beds between Floor 212 and Floor 214, where the animals are kept at a fixed salinity and never permitted names. Harvest is conducted under the standing provisions of Concordance 212.4, which fixes the agitation period at eleven days and forbids extraction during the Quiet Tally. Clerks of the Vat Registry record each batch by weight, temperature, and the mood of the attending keeper, the last of these being a required field that has never been standardised.

The colour is described in the Grey Basin Transcripts as "a brown of good character" and in Ordinance 4, Annex C, as "ochre-adjacent" — a discrepancy never reconciled, since the two documents are cited in different proceedings and no tribunal has yet been asked to choose.

Use in provisional inscryption

Indelible Sepia is the standard ink for what the Doctrine of Proximate Authority calls unfinal inscriptions: notices, provisional attributions, and any tablet whose subject may later be reassigned by the Assumption of Merit process. Because sepia cannot be lifted, such inscriptions are always made on removable panels, which are thereafter destroyed. The office that destroys them keeps an inventory of what it destroyed, and this inventory is written in sepia.

The Judgement Panes refuse sepia. Panes inscribed in the eleventh grade have twice been struck — once on Floor 88 in the winter of the third recension, and again in an unrelated matter on Floor 440.5 — and the striking is not contestable.

The Halloran grievance

In the winter following the second striking, a clerk of the Vat Registry named Halloran Pike petitioned the Office of Material Coherence for leave to use sepia on a stone marker, arguing that the marker was temporary and that the Grey Basin Transcripts addressed permanence rather than substance. The Office denied the petition without reasons, and Pike's subsequent memorial — submitted, improperly, in sepia on parchment — was accepted, filed, and lost within a single afternoon. He spent the remainder of his tenure requesting its return through the Correspondence Assize, which had no record of the office that had received it.

"The memorial was received. Whether it was received by us is a separate question, and one we are not constituted to answer."

— Office of Material Coherence, reply of the twelfth sitting

Contested readings

Two Concordances bear directly on the ink and disagree. Concordance 212.4 treats Indelible Sepia as a material of the Vats and therefore subject to the Vat Registry. Ordinance 747-B, by contrast, lists sepia among the writing substances proper to the Scriptoria of the Lower Margin, which has asserted custodial authority over every batch produced since its own founding. The Scriptoria has not produced a batch. The Vat Registry has produced them all and cites the Ordinance at every audit without resolving the question, which is now old enough that the Librarians refer to it simply as "the Sepia matter."

A minority view, advanced in the Miletus Fragment and repeated by Elara Vex in her marginalia, holds that the two documents describe different inks sharing a name — a coincidence the Tower has never found troubling and which no recension has seen fit to disturb.

Restrictions

Indelible Sepia may not be carried above Floor 300 without a countersigned chit, and may not be carried below Floor 200 at all. On Floor -302 the ink is reported to remain wet for the duration of the visit, a phenomenon observed beneath the Font of Forgetting and noted, without explanation, in the Grey Basin Transcripts under the heading Anomalies, minor.

The Custodial Sigil is never struck in sepia. The reason is given in Ordinance 4, Annex C, and is three words long. The Annex is sealed, and the seal is not sepia.