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Kokak 7222 max resolution


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#1 David Doko

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Posted 01 February 2009 - 03:16 AM

I've been reading the Kodak technical sheet on 7222 but I'm unable to understand the "resolving power" data. I'd like to know the theoretical best resolution of 7222, and I know it has a relationship with contrast. But I'm wondering if someone here can explain it better than what's printed on that tech sheet and how to interpret the contrast data.

URL is:

http://motion.kodak....h7222.htm#image

Edited by David Doko, 01 February 2009 - 03:20 AM.

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#2 Charles MacDonald

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Posted 02 February 2009 - 11:03 PM

I've been reading the Kodak technical sheet on 7222 but I'm unable to understand the "resolving power" data. I'd like to know the theoretical best resolution of 7222, and I know it has a relationship with contrast.
http://motion.kodak....h7222.htm#image

The explaination of the relationship between resolving (Ie Line pairs per milimeter) and contrast is not simple and clean cut.

The most understandable explantion I have found is the Dr. C.E. Kennith Mees book "From Dry Plates to Ektachrome film" which you may be able to find in a technical library or on a used book site like ABEbooks.
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#3 Brian Pritchard

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Posted 04 February 2009 - 04:41 AM

Because resolution is tied to contrast the best way to mesure definition is using MTF (Modulation Transfer Function). You will find MTF curves for all the Kodak stocks on their website.


The Kodak explanation is:

"MTF curve - This graph shows a measure of the visual sharpness of the film. The x-axis, "Spatial Frequency", refers to the number of sine waves per millimeter that can be resolved. The y-axis, "Response", corresponds to film sharpness. The longer and flatter the line, the more sine waves per millimeter that can be resolved with high degree of sharpness, and the sharper the film is."

"MTF curve - This graph shows a measure of the visual sharpness of the film. The x-axis, "Spatial Frequency", refers to the number of sine waves per millimeter that can be resolved. The y-axis, "Response", corresponds to film sharpness. The longer and flatter the line, the more sine waves per millimeter that can be resolved with high degree of sharpness, and the sharper the film is."

Mtf has the advantage that you can measure the MTF of lenses, printers, projectors and so on. The final result will be the product of all the MTF percentages. For example if a film has an MTF of 10% at 80 cycles/mm and the lens has an MTF of 70% at the same frequency the result on the film would be 7%.

Brian
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