film latitued

[Ram Shani]

hi

 

i am about to shot a short film 16mm

 

i am going to use VISION 250D and VISION2 500T

 

looking at kodak web site the technical deta indicats for buth films

 

that -2 2/3 under is 3%black

(18% gray card)

and 2 1/3 over is white.

 

thats to say the latitude is 5 stops.

 

but then you look at the pictures and you see there is almost 5 stops under

and 4 stops over(and you still see same detail)

 

what is the latitude of those negatives???

 

ramdop

[Kevin Zanit]

I have never tested latitude with paper work.

 

I test it with camera work.

 

The best thing would be for you to test your latitude all the way through to print (or wherever your project will live). In other words, test it with YOUR metering style, YOUR lab's chemistry, and any other variables that could come into play.

 

Also, there is a difference between dynamic range (latitude) and texture range (zone II through VIII). In other words; you should look at practical latitude (what I consider to be the above, your film still holds detail) versus actual latitude (zone I - IX).

 

 

 

The moral of the story: Test it yourself for the most accurate results.

 

 

 

Kevin Zanit

[John Pytlak RIP]

I agree, shoot tests. As you go from very underexposed to very overexposed, the characteristics of the image will change. For example, underexposure will lose shadow detail and the blacks will be less dense in the final print. Gross overexposure will compress the highlights, and produce a very dense negative that is more difficult to print or transfer. But all of these exposure conditions will give you an image, and may actually enhance the "look" you want. Certainly, modern color negative films have wonderful latitude, and a stop over or under is not a recipe for disaster.

[Michael Nash]

Also, there is a difference between dynamic range (latitude) and texture range (zone II through VIII).  In other words; you should look at practical latitude (what I consider to be the above, your film still holds detail) versus actual latitude (zone I - IX).

This also brings up a good question: how does Kodak define "latitude"? I've always understood that to mean how much you can over- or under-expose an image and recover a decent looking image. That's different than the "dynamic range," which is how much extreme bright or dark detail the film can capture.

 

There is a HUGE difference between these two concepts -- some films will capture detail down to five stops under, yet I wouldn't dare tell someone the film has "five stops of underexposure latitude" and have them think they can underexpose five stops and still recover an image! By the same token, a fast grainy film may look like crap if you underexpose it, meaning it has NO latitude for underexposure. Yet it may still capture detail several stops under key.

 

Have I got the terms wrong? Or am I being overly nit-picky? To me it seems important to draw this distinction, even if almost everyone says "latitude" when they're really talking about dynamic range.

[John Pytlak RIP]

Yes, "latitude" is the amount you can under or overexpose an image and still be satisfied with the results. Dynamic range of film is very high, and is usually considered to be the log exposure range that constitutes the "straight line" portion of the film's sensitometric characteristic. But image detail is also captured by the non-linear "toe" and "shoulder" portions of the curve:

 

http://www.kodak.com/US/en/motion/support/...html#understand

 

Work by Kodak image scientist Dr. Roger Morton and his team, reported in a technical paper published in the February/March 2002 SMPTE Journal found that the dynamic highlight range of color negative film was about 16 stops.

[Michael Nash]

Work by Kodak image scientist Dr. Roger Morton and his team, reported in a technical paper published in the February/March 2002 SMPTE Journal found that the dynamic highlight range of color negative film was about 16 stops.

By "highlight range" does that mean 16 stops above mid gray? Or 16 stops total, black to white? I understand that includes information in the extreme (and gamma compressed) toe and shoulder.

[John Pytlak RIP]

I believe that figure of "highlight range" was the number of stops above a mid tone gray. Dr. Morton's tests included shiny metal objects that had specular reflections. Film was able to capture image detail in those speculars much better than any digital camera.