There were speed ratings as far back as the '90's...and not the 1990's either. I still use Ortho film mostly in large format. I used to use super plenechrome press and super speed ortho, super speed ortho was rated at about 125. BUT, in the lovely little papers that came with it it gave all the modifiers for filters timr of day, and time of year. 125 speed was for a bright sunny day, between 10:00am and 3:00pm, in the summertime. Shooting snow scenes early or late day could slow down to asa 10.
Quote Originally Posted by dwross View Post
Oh, heavens, no. At the 45th parallel, this recipe

gets 6 to 40, depending on time of year and time of day, and to a lesser extent, altitude. (It is impossible to place a single ISO number on anything but panchromatic films. If you read otherwise, this is a red flag to suspect the experience of the source.)