Need some help with 1950s films

[N467RX]

And when were the specs redefined?

[2F/2F]

I cannot seem to get to the second page of this thread.

There...that did it.

[nworth]

When the ASA procedures for measuring film speed changed, the metering standards did not. You use new films in old cameras the same way as old films, using the rated speed or your personal EI and setting the camera for the shutter speed and f/ number indicated by the meter.

The new way of measuring film speed did more than just eliminate the safety factor. It also changed the standard developing methods and a few other things involved in the speed determination. While for most films, the rated speed doubled (or nearly so), there were significant variations from film to film. Around that time films were also changing a quite a bit, so the picture is quite confusing.

[cmacd123]

And when were the specs redefined?

Apperently in the Mid 1950's era.