110 Technical Guide
110 cassettes are of two types: with a long flange or short flange. All modern Lomography cassettes have the LONG flange and all cassettes under 400 ASA both ancient and modern have the LONG flange.
400 ASA cassettes should have the SHORT flange to tell the camera to set a high shutter speed or, more likely to stop down the lens by a released pin. We will verify this as we see more original cassettes for processing that are 400 ASA.
All LONG -flanged cassettes will set LOW range setting. 110 cameras could support LOW and HIGH sensitivity from 1976 by introducing a pin in the film chamber. Default operation was 'pin depressed' as the LONG flange on the cassette covered the pin.
When the HIGH range cassettes were introduced after 1975, the pin would now be released and told the camera's electronics to assume a faster film so use a smaller aperture or faster shutter speed.
This operation was never documented in the manufacturers' manuals we have seen.
What do the LOW or HIGH ranges mean in terms of ISO speed?
This is a grey area - literally. Simple camera models either had no support for HIGH range or would support HIGH above a certain serial number, or would not tell you there was even a HIGH range possible. This meant that customers would use 400 ASA films in their cameras and all the results would be over-exposed, as there was no pin in the camera to tell the unit what to set the lens or shutter speed to get correct exposures.
The vendors could choose what ASA film speed to match to the LOW or HIGH ranges. There were no guidelines from Kodak, whose own Ektra cameras were optimised for Kodak film speeds of 80 ASA (speed of the first 110 films in 1972)
So a) check if your camera has a pin in the film chamber that is always bottom right with the rear of the camera facing you. There will be a small depressable pin in plastic or metal. Do not remove the the pin and b) check the exact manual to match your camera model to get the definitions of HIGH and LOW ranges translated into ASA speed.
No 110 camera manufacturer even mentions the LOW/HIGH pin in their instruction guides