Dynamic Range for Kodak CN400BW

brankop said:
RE: "I assume you made different exposures?"

No it is a single exposure. The target consists of two rows with 14 patches in each row. The difference between the neighboring patches is 1/2 stops. Therefore each row has dynamic range of 7 stops.

Target is transparent and back-illuminated. The exposure was done in dark to minimize veiling glare effect.

This test might be somewhat unfair to film since film's characteristic curve is nonlinear (both in highlights and shadows). Hence I could expose film a bit longer so the highlights get compressed and that should bring more patches from dark.

Any thoughts?
Click to expand...

How do you meter?

Films are very tolerant to over-exposure. So I would suggest expose for the shadow, and examine the densities of adjacent patches on the negative to determine its "dynamic" range, not the scanned digital copies on a monitor. Otherwise you might be examining the dynamic range of either your scanner or your monitor.
 
I know that this looks like reinventing the wheel, but I put my 14 stops target directly onto the scanner to see if the the scanner is a limiting factor in the test. The re-sized image is attached. I can clearly see 11 stops dynamic range which is close to the 11.3 stops that the scanner manufacturer is claiming.
 

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  • Target_14stop_scan.png
    Target_14stop_scan.png
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This film is my favorite black and white stock (I just happened to pick up some 135 fresh stuff off the big auction site tonight at a good price...). I like it so much it's all I shoot for b&w. Traditionalists be darned -- I don't care. Sharp, rich tones -- beautiful. I prefer its look to silver. I also prefer it to XP2 Super. I like it so much I sold all my development stuff. T'ell with all that paraphernalia and chemicals. This question is not a snark. I know that dynamic range is a technical concern and all -- but who cares? Do you like how the film renders images? Your eye should be the only gauge you need imo, not some dynamic range graph. Same with lenses -- some of my favorites would certainly lose the MTF wars, but I simply like the way they render images. No analysis required. Just the observer's subjective taste and opinion.
 
Can't find the BW400CN locally anymore. Guess I'll have to go the bulk purchase route, and buy online.

I'm with you, Nick. I really like the way I can use it without filters and still get plenty of contrast without losing details.

PF
 
Chromogenic B&W 400 ISO film is EI 200 if not EI 100 at best in real ( contrasty light) circumstances. If you expose richer, you will get more detail in the shadows, while the highlights will still retain some gradation. However, if you are after a rich tonality and extended gray scale detail, do yourself a favour, and shoot a film like Tri X or HP5+. Tri X @ EI 250 in Diafine will have a gazillion stops of range, and shot between EI 125 and 250 and developed in D76 1+1 will never fail to amaze you.

Tri X @250 in Diafine

MF20141216 by mfogiel, on Flickr
 
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