ORWO Chrom UT 18 — 135 slide film, ISO 12

Description

ORWO Chrom UT 18 is an expired 135 colour reversal slide film. Its nominal speed is DIN 18 / ISO 50, but because of age and unknown storage conditions, I recommend exposing it at EI/ISO 12–25 with bracketing. Results are not guaranteed.

Why does the listing say ISO 12 if UT 18 is ISO 50?

UT 18 stands for Umkehr (reversal) + 18 DIN, which corresponds to nominal ISO 50. The ISO 12 in the listing is the practical recommended exposure index for shooting this particular expired batch. After decades of storage, the actual speed has dropped considerably, so it is safer to start at EI 12–25 and bracket.

Character and risks

Slide films endure decades of storage much worse than black-and-white negatives, due to their complex multilayer chemistry. Typical issues with old ORWO Chrom include: reduced sensitivity, chemical fogging, colour shifts, and brittle gelatin. A green or magenta cast is often possible, but the exact result depends on the individual roll and its storage history. Handle the roll with great care.

How to shoot

Old slide film has very narrow exposure latitude. The colour-negative rule of '+1 stop per decade of age' does not apply reliably to slide film. Set EI/ISO 12–25 on your camera or light meter, and always bracket: shoot the same scene at 0, −1 and +1 EV. Avoid overexposure.

Development

Do not develop in standard E-6 — the high process temperature will destroy the old layers. The original process is ORWO 9165. FilmLabStore offers three options: hand development using original ORWO chemistry, colour cross-process (C-41, conceptual colour effect), or cross-process in black-and-white chemistry (monochrome, the safest option if storage history is unknown).

Specifications

FAQ

Why does the listing say ISO 12 if ORWO Chrom UT 18 is nominally ISO 50?

DIN 18 equals ISO 50 — that is the nominal speed of fresh film. ISO 12 is the practical recommended exposure index for shooting this particular expired batch. After decades of storage, real sensitivity has dropped significantly, so it is safer to start at EI 12–25 and bracket exposures.

How do I shoot expired ORWO Chrom UT 18?

Set EI/ISO 12–25 on your camera or light meter. Always bracket: shoot the same scene at 0, −1 and +1 EV. Avoid strong contrast where slide film loses detail in both shadows and highlights simultaneously.

Can ORWO Chrom UT 18 be developed in standard E-6?

No. Standard E-6 is not suitable for this film — the high process temperature will damage the old emulsion layers. The original process is ORWO 9165. Cross-processing in C-41 or processing in black-and-white chemistry are also possible options.

What results should I expect?

Results depend on storage conditions, which are unknown. Colour shifts, reduced contrast, fogging or partial image loss are all possible. This film is for experimenters, not for predictable results.