Kodak films: what does X represent?

Photo Engineer · Jan 1, 2013

In broad terms, ASA and ISO are the same to me. I use old meters with impunity! They are all marked in ASA and they still work. My newest automatic cameras use ISO in the internal meters and I still get the same density (within experimental error).

Yeah, you are right, kinda, and so am I. There actually is so much "fudge factor" in both that it is hard to say. Mid scale speed taken from the straight line, is what we use in the lab! The toe can lead to imprecise results, and the best method is the inflection point of the toe from fog, but you don't take pictures there. It is the absolute speed point though.

PE

AgX · Jan 1, 2013

Photo Engineer said:
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

As I said above:

X=ASA 100 (and double and tri refer to the number of steps of doubling speed), as long as Panatomic-X is not spoiling the game....

Thus so far I'm not convinced.

It must mean something else. What about potion No.9...?

pentaxuser · Jan 1, 2013

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

However this may be the true marketing speak. X also represents the "unknown" aka "secret and special". So it was the practical film engineers who had a big say in the film nomenclature and the MAD men who were instrumental in the developer's name

pentaxuser

Brian C. Miller · Jan 1, 2013

Are you guys sure that it isn't Newspeak for something? Double-X Plus-X Good-X?

Photo Engineer · Jan 1, 2013

Well, AgX and David Lyga essentially say the same as I did. The X in film names refer to speed increases. Thus the 3 of us agree. Whether rue or not remains to be seen.

I would like to suggest that the X in Microdol X refers to a secret ingredient. ! I have the name of that sitting right next to me in a little pocket note book that I had with me when either Dick Henn or Grant Haist gave it to me!!

Panatomic X grew (IIRC) from an original formula by having the same grain but higher speed. The earlier film was not named Panatomic, but I can check on that if I get unlazy and look it up.

PE

Bill Burk · Jan 1, 2013

Looking at the cross-section in "Making Kodak Film" makes me wonder... do all these X films have the "Fast Emulsion Layer" above the slower, ordinary layer? Maybe that's the X

AgX · Jan 1, 2013

Maybe it is a temptation by the Goddesses of Kodak Park...

And we should keep our virtue and learn that some things should stay veiled.

mopar_guy · Jan 1, 2013

So where is the "X" in Super Panchro Press Type B?

zsas · Jan 1, 2013

Mopar - Haaa, never heard of it! I had to search what you were talking about!! Yeah I'm with you, a 'X' woulda been better than the 'B'. Think we know PE wasn't around when B was named
http://image-banque.com/IAG/images/pce122661.jpg

Photo Engineer · Jan 1, 2013

Fast above slow. Hmmm, see Kofron et. al. for that one! Yes, that ordering is used in color films and is a patented Kodak method of speed vs grain for some films.

And the X film designations at this point are just a guesstimate. Next chance I get, I'll ask George Eastman, but I am not in a hurry to ask him if you get what I mean.

PE

mopar_guy · Jan 1, 2013

Photo Engineer said:
Fast above slow. Hmmm, see Kofron et. al. for that one! Yes, that ordering is used in color films and is a patented Kodak method of speed vs grain for some films.

And the X film designations at this point are just a guesstimate. Next chance I get, I'll ask George Eastman, but I am not in a hurry to ask him if you get what I mean.

PE

Don't be in a hurry to ask him, he may not remember.

Bill Burk · Jan 2, 2013

I'm still reading 'The Photographic News' from 1896 where Oakley Norris was a bit annoyed that he had to switch from yellow safelights back to red safelights to develop Isochromatic plates.

Ian Grant · Jan 2, 2013

I've just found the article in the BJP Almanac 1939 for the new family of films Pan X, Plus X and Super XX, I guess if I look in the 1940 copy I'll find Tri X which is listed in my 1940 Kodak Professional Catalogue but only available as a sheet film.

The Kodak advert states the films were released in 1938, the 1939 Almanac was published toweards the end of 1938, here it is:

This is the first mention of the X

Ian

dwross · Jan 2, 2013

Bill Burk said:
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...

Bill,

I believe you've mixed lists. "Ordinary" doesn't refer to an emulsion speed, but rather to the plate being colorblind, i.e. unsensitized to anything but UV and a bit of violet light. It is by default very slow, but an ordinary plate can still be different degrees of slow.

It's been my understanding for so long that I've forgotten where I learned it (and could therefore be wrong!) that the X designation referenced chemists' notation for halides (in photography: chloride, bromide, and iodide). AgX is shorthand for any silver halide.

bsdunek · Jan 2, 2013

Photo Engineer said:
Fast above slow. Hmmm, see Kofron et. al. for that one! Yes, that ordering is used in color films and is a patented Kodak method of speed vs grain for some films.

And the X film designations at this point are just a guesstimate. Next chance I get, I'll ask George Eastman, but I am not in a hurry to ask him if you get what I mean.

PE

Ya, but then you won't be able to get the answer back to us.

Ian Grant · Jan 2, 2013

Seems the X family was larger wit Ortho X as well, see 1940 advert which includes Tri X:

In contrast Ilford had just introduced their second generation of modern films FP2 & HP2.

Ian

dynachrome · Jan 2, 2013

In High School I bulk loaded film for my Minolta 16 PS. The film I used was Eastman Four-X single edge perf motion picture film. It had an ASA speed of 500. Double-X was 250 and Plus-X was 125. In the future if I want to use the Minolta I will probably get a slitter and use 35mm stock. I don't think the Minolta uses the perforations anyway.

strix1973 · Jan 2, 2013

It may be wrong but I recall reading that in 1937 or 38 the x designations were added to newly designed still camera films to distinguish them from motion picture film due to their having an antihalation layer and and could be developed to a higher contrast as well as being equally efficient in daylight and artificial light. Panatomic x was the still version of the cine Panatomic with finer grain for enlargements. Plus x was the still version of Kodak cine ss pan and had 50% more speed.

nworth · Jan 2, 2013

It is probably just a marketing label. There have been a lot of X films, and not all have been commercial mass market items. Not all have been black and white, either (e.g. Kodacolor-X). Some have been motion picture films (Eastman Plus-X, Background-X, Double-X, Tri-X, 4X, XT, etc.)

Photo Engineer · Jan 2, 2013

All films have an antihalation layer of some sort or another. You have to go way way back to find some without such protection.

PE

Ian Grant · Jan 2, 2013

strix1973 said:
It may be wrong but I recall reading that in 1937 or 38 the x designations were added to newly designed still camera films to distinguish them from motion picture film due to their having an antihalation layer and and could be developed to a higher contrast as well as being equally efficient in daylight and artificial light. Panatomic x was the still version of the cine Panatomic with finer grain for enlargements. Plus x was the still version of Kodak cine ss pan and had 50% more speed.

No because Kodak introduced exactlysame films as Motion Picture film around the same time in 1938/9. The X was similar to Tmax just a new family of films and to distinhuish them from earlier products so just a marketing tool as nworth says.

Welcome to APUG BTW

Ian

walbergb · Jan 2, 2013

The answer you seek is simple: the letter W was already spoken for and X was the next available letter

jloen · Jan 2, 2013

Two days ago my contractor told me that PEX tubing was named for polyethylene that is cross-linked, "so they put an X on the end". I immediately thought of Tri-X film. But there may be no connection...

Kodak films: what does X represent?

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