The Opticon OPT file format

Image load file · one row per page · the cross-reference between Bates numbers and TIFF files

What it is

An OPT is the image half of a production. Where a DAT says what each document is, the OPT says where each page lives: one comma-separated line per Bates-stamped page, pointing at the single-page TIFF or JPEG in the volume. Review platforms read it to display documents; production QC reads it to verify that every page that was promised is actually there.

The name comes from Opticon, the image viewer whose convention it follows; IPRO, Concordance, Relativity and the rest all import it.

The seven columns

#	Column	Content
1	Image key	The Bates number of this page; by convention equals the image filename minus its extension
2	Volume label	Which volume/disc of the production the image sits on, e.g. VOL001
3	Image file path	Relative path to the page image, e.g. IMAGES\001\ABC0000001.tif
4	Document break	Y on the first page of each document, empty on every continuation page
5	Folder break	Folder boundary flag — reserved in most productions, usually empty
6	Box break	Box boundary flag — reserved, usually empty
7	Page count	Number of pages in the document, written on the document-break row only

What a document looks like in it

Three-page document ABC0000001–ABC0000003, one line per page, Y on the first only, count on that same line:

ACME0000001,VOL001,IMAGES\001\ACME0000001.tif,Y,,,3
ACME0000002,VOL001,IMAGES\001\ACME0000002.tif,,,,
ACME0000003,VOL001,IMAGES\001\ACME0000003.tif,,,,

The trailing commas on continuation rows are load-bearing: they are the empty columns five to seven. A writer that trims them emits five columns where seven are expected, and a positional reader then interprets the path as a folder break.

Why the Y flag is the whole ballgame

Nothing else in the file says where one document ends and the next begins. The Bates sequence implies it, but the flag is what platforms actually key on. That makes the two characteristic OPT errors silent:

A dropped Y merges two documents into one — the platform believes a 40-page email and the contract attached to it are a single document.
A stray Y splits one document in half, and its page count no longer matches either half.

Neither stops the import; both surface later, when a document has the wrong page count or the wrong endorsement. A checker reads each break row and compares the declared page count with the number of rows that actually follow it until the next Y — the discrepancy is invisible from any single row.

Checks that only exist against the DAT

The most useful OPT findings need the metadata file alongside: document counts side by side (DAT rows vs Y flags), membership both ways, and every continuation page tested against the BEGBATES–ENDBATES ranges. A page outside every declared range is either a stray image or a wrong range; you want to know before production. The Bates checker runs exactly this when you load a DAT and an OPT together.

Encoding and line endings

OPT files are usually Windows-1252 or plain ASCII with CRLF line endings, but paths are the part that matters: a custodian folder with an accented character in its name is exactly where a mis-decoded path silently stops resolving to a real file. Verify UTF-8 strictly, fall back to cp1252, and honor BOMs — the converter does this on load and writes the same family back.