Overview
ISO 6038:1993 defines standardized dimensions and locations for transverse overlap and butt splices used on 70 mm, 65 mm, 35 mm and 16 mm motion‑picture films and prints (including magnetic or photographic sound records). It is the second edition (1993) and updates the 1985 edition. The standard covers laboratory and projection splice types, tolerances for alignment and shrinkage, and practical splicing recommendations to ensure optical, mechanical and audio integrity.
Key topics and technical requirements
- Scope and film gauges: Applies to 70 mm, 65 mm, 35 mm and 16 mm film/prints; dimensional tables and figures (Tables 1–5, Figures 1–5) specify splice geometry for each gauge and splice type. It assumes nominal film shrinkage up to 0.2% and recently made splices.
- Splice types: Specifies laboratory overlap splices (Type 1) and several projection types (Types 2–5) including non‑anamorphic and anamorphic projection splices and tape‑applied splices for prints.
- Dimensional limits: Film width at the splice shall not exceed defined maxima (for example 70.05 mm, 65.05 mm, 35.03 mm, 16.00 mm). Table 5 gives limits on small detail dimensions, e.g. E max 0.33 mm, G max 0.05 mm.
- Alignment and tolerances: The spliced film edges must meet at an angle of 180° ± 4′; deviation when placed against a straight edge must not exceed 0.15 mm per 130 mm (0.006 in per 5 in).
- Mechanical strength: Splices must withstand a tension at least 50% greater than the projector gate tension for the film width.
- Perforations and audio: Perforation holes must remain clear at splices. If a photographic soundtrack modulation at the splice produces bias lines narrower than 0.05 mm, the soundtrack should be blooped or opaqued to prevent audible artifacts.
- Recommended practice: Bevelled/scraped overlaps are preferred (scraped area 0.03–0.08 mm narrower than the overlap), use optically clear transparent tape for butt/overlap tape splices, avoid air bubbles, and ensure tape covers at least half a frame on each side.
Applications and users
ISO 6038 is primarily used by:
- Film laboratories and post‑production facilities for negative and intermediate splicing
- Projectionists and cinema technical teams preparing theatrical prints
- Film archivists and restoration specialists ensuring compliant, durable splices
- Manufacturers of splicing equipment, splicing tapes and projector components
Adopting ISO 6038 ensures consistent splice geometry, reduces projection artifacts (white lines, audio clicks), and improves mechanical reliability during handling and projection.
Related standards
Relevant ISO references cited in Annex A include:
Open preview (PDF)Cinematography — Splices for use on 70 mm, 65 mm, 35 mm and 16 mm motion-picture films — Dimensions and locations