Trivia: Plus-X, Double-X, Tri-X

[varjag]

Where those names come from?

In particular, the 'X' postfix. Does it signify ASA 100/125? Which sensitometric system might have used that?

 

[cmedin]

Plus-X was in the earlier days ISO 40, then 80, so I don't believe it has anything to do with speed rating like you think. Also, there was Super-X, Super-XX and Panatomic-X...

 

[Tom A]

I must admit that I never thought about the nomenclature for the Kodak films, even though I have used them extensively over the decades.
The early 1953 tri X was actually rated at asa 200 and later it was bumped up to 400.
The SuperX,Super XX were 100asa and 250asa (daylight) respectively. Maybe here it makes sense 2 times X would give you XX.
The current Double XX is rated at 250 in daylight and 200 in tungsten. The Plus X movie stock is rated at 125 daylight and 80 tungsten.
Panatomic X was nominally rated at 32, later upped to 50 and most of us shot it at 80-100 asa. Must be frustrating for Kodak trying to tell us what speed to use and everybody ignored them!
Maybe we should email Kodak and find out about this. Sounds like a Trius project!

 

[Gumby]

The current Double XX is rated at 250 in daylight and 200 in tungsten.

Which film is the "current" Double XX? Here's the professional B&W line-up currently on the Kodak site:

http://www.kodak.com/global/en/professional/products/blackWhiteIndex.jhtml

 

[varjag]

Interesting.. so speed doesn't seem to be it.