Kodak films: what does X represent?

[Dali]

Hi,

It might be a silly question for some of you but I wonder why Kodak uses "X" in their film codes: Double-X, Plus-X, Tri-X, etc... Does "X" have a special meaning regarding film characteristics or is it only a commercial trick?

have a great 2013 year!

 

[pentaxuser]

It's an excellent question. I look forward to the answer or answers

pentaxuser

 

[Mark Crabtree]

Welcome to APUG.

I'll be curious to hear if anyone has an explanation, but even if they don't it isn't necessarily a "trick", just a name.

I'll throw out my best guess here - "exposure". Plus-X - more exposure for the same settings as whatever preceded it. Double-X -twice that. Etc. It is just a convention now.

If we figure this out, then we can take on "chrome", which got to be the common nickname for color transparencies. Verichrome I understand, but not how they got from that to Kodachrome.

 

[removed account4]

my guess is it is just a gimmick like the word kodak, easy to remember, means nothing

 

[AgX]

X = ASA 100

 

[Ian Grant]

Pan X was the slowest film available in the late 1930's in Kodaks new series of modern films which included Super XX and Tri X, these were made in in least 4 countries, US, Canada, UK and Hungary.

Plus-X and Double X were later films.

Ian

 

[Vaughn]

Pan-X at ASA 32...such a wonderful film!

 

[AgX]

X = ASA 100

Well, with Panatomic-X in mind that does not make much sense...

Do we have to expect from Kodak designations to make sense?

 

[Bill Burk]

I don't know but guess that it goes back to the glass plate speeds...

Slow, Ordinary, Rapid, Extra Rapid, Double Extra Rapid.

Where the X is from Extra.

I've had a hard time finding how these speeds translate to ASA/ISO speeds. Seems any reference that knows these speeds predates ASA...

 

[pentaxuser]

I think we need a Kodak source called PE There has to be a kind of reasoning behind the use of X doesn't there?

pentaxuser

 

[David Lyga]

Am I naive here? "X" = "TIMES". Double X was 2 times the 'standard' speed and Tri-X is three times the 'standard' speed. Plus-X is a bit faster than the 'standard' speed since 125 is a bit faster than 100. And NO, Tri-X is not 400 but really about 300. Panatomic-X I do not have an answer for. But, again, maybe none of my answers were real answers! - David Lyga

 

[MattKing]

I think we need a Kodak source called PE There has to be a kind of reasoning behind the use of X doesn't there?

pentaxuser

I don't think PE is old enough to know.

Happy New Year PE

 

[zsas]

I don't know but guess that it goes back to the glass plate speeds...

Slow, Ordinary, Rapid, Extra Rapid, Double Extra Rapid.

Where the X is from Extra.

I've had a hard time finding how these speeds translate to ASA/ISO speeds. Seems any reference that knows these speeds predates ASA...

Think you might have it (just my guess after finding the below Kodak ad from '39 announcing three new films PlusX, SuperXX, PanatomicX)....

http://farm5.staticflickr.com/4148/5210725555_8f8ccd0a74_o.jpg

 

[Christiaan Phleger]

Well in Microdol-X the X represents the inclusion of the secret mercapto. Do a APUG search about Microdol-X where PE and I go back and forth about the mercapto.

 

[zsas]

So X is just a varriable used time to time to differentiate Y we think? Kinda like Super XX is to Plus X as mercepto leads to Microdol X

 

[darkosaric]

Am I naive here? "X" = "TIMES". Double X was 2 times the 'standard' speed and Tri-X is three times the 'standard' speed. Plus-X is a bit faster than the 'standard' speed since 125 is a bit faster than 100. And NO, Tri-X is not 400 but really about 300. Panatomic-X I do not have an answer for. But, again, maybe none of my answers were real answers! - David Lyga

This sounds very logical to me.

 

[pentaxuser]

David's explanation sounds as if it may be right. In those far-off days we spoke about the "times tables" referring to multiplication tables and people were used to the X symbol to mean the instruction "multiple"

pentaxuser

 

[zsas]

^ But David's theory doesn't work on the Microdol-X example....thinking X is used to mean Y....whatever that Y maybe

 

[Bill Burk]

I found an exposure chart and worked backwards from "Sunny 16" to find what I think might have been "equivalent" ASA speeds for the different plates.

There wasn't as much difference between the speeds as I thought there would be... Maybe this is why they tried to run Hurter and Driffield out of town...

Photographic News for Amateur Photographers, Volume 51


Ordinary Plate EI appx 1.25

Medium Plate EI appx 2

Rapid Plate EI appx 3.75

Extra Rapid Plate EI appx 5.00

Ultra Rapid Plate appx EI 6.25

 

[removed account4]

if you substitute "speed" for "x" in the old film ad andy posted
super speedy speed,
plus speed, panATOMIC speed

its just futuristic babble
its the 30s, post industrialism,
art deco at its finest ...

wasn't the bromoseltzer guy's sub atomic plane
powered by bromo X ...

i think the guys from MST3K might know for sure ...

 

[Photo Engineer]

I am not old enough to be "in" on the details of this naming stuff for films, but I do believe that David is right.

X means times. So Super X was 2x the speed of an earlier film, and Super XX was 2x the speed, while TriX is 3x the speed. So, we have 100, 200 and 400. And BTW, Tri X is supposed to be 400.

PE

 

[Bill Burk]

I don't know about rocket boosters... but I'm going to be buried reading "Photographic News for Amateur Photographers" for a while, this is fun reading.

 

[Bill Burk]

I am not old enough to be "in" on the details of this naming stuff for films, but I do believe that David is right.

X means times. So Super X was 2x the speed of an earlier film, and Super XX was 2x the speed, while TriX is 3x the speed. So, we have 100, 200 and 400. And BTW, Tri X is supposed to be 400.

PE

Didn't all the films come out under the earlier ASA definition which included a safety factor?

 

[removed account4]

hi bill

i have an old DREM INSTOMETER from around 1937ish
and there are no asa - type film speeds on it
it just has scheiner speeds ... maybe when asa values were established
they established the "X"factor
where's george when we need him ?!

john

 

[Ian Grant]

Didn't all the films come out under the earlier ASA definition which included a safety factor?

Yes they did.

But it's the family of films introduced around 1939 that were based on the X factor, Pan X, Super XX and Tri X which came out at the same time so there's no reference back to earlier films.

This family of films was introduced to compete with Ilfords new Pan F, Fine Grain Panchromatic and Hypersensitive Panchromatic which came out slightly earlier and still exists as Pan F, FP4+ and HP5+.

Ian