what does "X" means?

[YongLee]

what does "X"means of  kodak 5222 DOUBLE-X?

[Will Montgomery]

Good question...In the still world, Panatomic X was the first X film in 1938. Then Plus-X, Super-X, Super-XX, Ortho-X & Tri-X. So there's a long tradition of X films just not sure where the original X came from. Xtra? Probably need a Kodak historian to let us know.

[Frederick Knauf]

When I became a product engineer working with Black & White Products being emulsion coated back in the mid-1990's, I asked the exact same question YongLee.  I never could find an "old timer" who could definitively give me the straight answer.

I built a B&W speed list of the following:

Plus-X 80D,  Super-X  125D,  Double-X 250, Tri-X 400D and 4X - 500D   

But one has to remember that even back in the early days, the film companies were looking for ways to improve the efficiency of light capture on the silver halide grains, so products did remain the same name and go through a speed increase.  That makes a straight "X = ## film speed" a little tricky, but from what I've gathered, it seems like the original late 1920's films an "X" could have indicated a speed of around 32-50 and later, that was increased to have an "X = 64" speed.

Frederick Knauf

Film Quality Manager, Eastman Kodak Co.

 

[Mark Dunn]

18 minutes ago, Frederick Knauf said:

"X = 64" speed.

This figures in well with the doubling of ASA speeds in the early 60s when the safety margin was removed- so "X" then became 125? 4x125=500 as you note. Although in stills, Panatomic-X stayed at 32. Hmm.

Incidentally, what a great forum when someone asks for a Kodak historian......and we have one. Talk about the horse's mouth.

Edited October 28, 2022 by Mark Dunn

[YongLee]

On 10/27/2022 at 11:47 PM, Will Montgomery said:

Good question...In the still world, Panatomic X was the first X film in 1938. Then Plus-X, Super-X, Super-XX, Ortho-X & Tri-X. So there's a long tradition of X films just not sure where the original X came from. Xtra? Probably need a Kodak historian to let us know.

ok thanks

[David Mullen ASC]

On 10/28/2022 at 10:27 AM, Frederick Knauf said:

That makes a straight "X = ## film speed" a little tricky, but from what I've gathered, it seems like the original late 1920's films an "X" could have indicated a speed of around 32-50 and later, that was increased to have an "X = 64" speed.

Frederick Knauf

Film Quality Manager, Eastman Kodak Co.

 

Though I don't think Pan-X disappeared when Plus-X appeared.  It might go back to when they doubled the speed from around 16 ASA to create Pan-X, I don't know.

[David Mullen ASC]

Looking around online, it seems that Kodak replaced a 1931 "Super Sensitive Cine Film" in 1935 with a product called "Super-X" than was then replaced by Plus-X in 1938, and probably around the time of Super-X in 1935, they renamed the slower Panchromatic stock "Pan-X" to go with Super-X.  I don't know that for sure, I'd have to read some old magazines from the time to see when the name "Pan-X" first appeared.

[Phil Rhodes]

Sounds to me like it's a bit of standard early-to-mid twentieth century advertising-speak, from a time where X worked as a generic claim to greatness and uniqueness without making any claim specific enough to fall to truth-in-advertising rules.

After all, The X-Men first published in 1963, and I'm not sure that really meant much beyond being backronymed into the name of a lead character. The book (then film) The Strange World of Planet X would be another great example, from 1958, but it was sold as Cosmic Monsters in the USA, so only partial credit. There are probably other examples of X in this sort of context from around that time. Even DC was in on it.