Kodak film specs

Shaun Joye · February 3, 2005

I'm currently a film student and have recently learned to desipher characteristic curves to calculate gamma, exposure range, etc. I was a little dissapointed to see that online the graphs for a lot of Kodak's motion picture film stocks lack detail and would be pretty hard to do any kind of calculations with. Does anyone know where I could get more detailed graphs from Kodak?

Filip Plesha · February 4, 2005

The PDF versions have virtually unlimited potential of accurancy.

I don't know how precise Kodak makes the PDF versions, but they can be perfected to infinity if the author wishes it.

John Pytlak RIP · February 4, 2005

The data in the on-line published data is not intended for scientific research, and has this disclaimer:

NOTICE: The data in this publication represent product tested under the conditions of exposure and processing specified. They are representative of production coatings, and therefore do not apply to a particular box or roll of photographic material. They do not represent standards or specifications that must be met by Eastman Kodak Company. The company reserves the right to change and improve product characteristics at any time.

Kodak will consider requests for more detailed data, when there is a business justification, and assurance that proprietary data will not be disclosed.

Shaun Joye · February 5, 2005

I may be misunderstanding something but by keeping this data hard to obtain it seems that kodak is doing a disservice to their customers. I mean if I want this technical data its because I'm interested in shooting Kodak stock and if Kodak's competitors want it they probably have the resources to get it themselves through testing. Am I missing something here?

John Pytlak RIP · February 5, 2005

Sorry, but there are cases where too much detail can aid competitors. The information is detailed enough for customers to use, but not so detailed that someone could use it to develop competitive products (e.g., LUTs or color correction matrices).

David Mullen ASC · February 5, 2005

There is also a point where, unless you are an efx person, you don't really need to know a film stock's technical details TOO far in depth. You don't want to take something designed by engineers to make art with and treat it like an engineer would. "You push the button and we do the rest" was the original add for the Kodak Brownie and to some degree it still holds true; don't get too wrapped up in the technology. Shoot the stock, put it through its paces, learn what it can do and can't do by judging the results with your eyes.

Dominic Case · February 7, 2005

Stock characteristics such as gamma, exposure range etc, are a function of each particular emulsion and the processing conditions at the time. While Kodak stick to tight manufacturing tolerances, and have similarly tight processing specs for labs to follow (and most do that pretty well), the published results can only be indicative of the aims (that's the disclaimer that JP mentioned).

If you really want more accurate results than you can get from the published pdf graphs, (for example with real exposure values, not relative logE values), then you will need to expose a sensitometric strip (or buy a roll of them from Kodak) and have it processed at the lab of your choice. Depending on what you want to do, they might just let you have one - labs use them every day for process control. There's realy no other way of getting real-world data.

Remember that the end product of your film images is something beyond the control of the stock manufacturer: at the very least it also includes the lab that processes the film. So it's not like expecting - for example - a lens maker publishing exact mtf data for their lenses.