B&W Film Dynamic Range

[Oren Grad]

I've also tried to differentiate between profiling and colour accuracy. If you read what I have said, it is that colour negative film is inherently more colour-accurate than colour reversal because of the masks. The so-called difficulty in profiling is a separate issue.

Helen, what is your recommended approach to profiling color negative? The question isn't intended as polemic - I've started tinkering with scanning color neg, and haven't yet nailed it to my satisfaction. If it matters, my current focus is on Portra 160NC and 400NC. Thanks...

[David Luttmann]

Helen,

I've used everything from the canned Imacon profiles to the IT8 as well. The problem with the IT8 is that they were designed in the 80s primarily for visual use. I've been using the Hutch precision scanner target with more accurate results.

I understand what you are saying with regards to grain and color accuracy, and I don't debate the greater dynamic range of color neg film over transparencies....but that said, one cannot be accurate in stating that color neg film is easier or more accurate to profile.....it's simply not. I actually started shooting some wedding work a few years back with MF Astia because I could obtain more accurate skin tones after profiling than was possible with Fuji NPS.

But, that said, when working with landscapes and other similar subjects, highly accurate color is rarely an issue for either film type....but grain / dynamic range could very well be.

Best regards,

[Helen Bach]

Oren,

For most work I do a variation of the EK telecine setup process that I am familiar with: ie I shoot a three-step card (Kodak 'Gray Card Plus' or the recent Macbeth card - both being black, grey and white) and balance the three by adjusting the curves, then I use that as the basis for all other scans in that lighting condition and exposure for that film, after setting the black and white points using the film DMax and DMin. This takes care of the uniform combination of masks and dye imperfections. The key thing is that the connection is made between the lighting in the scene and the scan before I then go and do whatever I feel like doing.

For more rigorous work I have used calibrated DSC colour bars and grey scale, but that is glossy and hence requires a little more effort than the matte Gray Card Plus or Macbeth. I happen to have the DSC chart because of my cinematography - I wouldn't bother paying for one for still photography, nor would I use such a system if I wasn't already familiar with it. How often do we need colour accuracy anyway? I'm sure that others on this forum will be able to offer a more suitable method than mine. With a disciplined approach you could use inCamera or similar, rather like one would with a digital camera. I have tried inCamera, but I stuck with what I was familiar with.

Here is what I was attempting to get at, but not explaining myself very well: using a Hutch target or an IT8/Q60 is a good way of matching the scan to the transparency, but it does nothing for matching the scan with reality because the reversal film itself does not do that. That doesn't matter so much - we are used to getting transparencies looking just like we want them to, and we are not likely to want a bang-on, technically correct representation (if there is such a thing with a three-colour system) unless we are copying art or something similar. As far as skin tones go, reality is the exception rather than the norm, isn't it?

David,

"...one cannot be accurate in stating that color neg film is easier or more accurate to profile.....it's simply not..."

I hope that I haven't stated that colour negative is easier or more accurate to profile - not least because I have some fuzziness about the exact meaning of 'profile'. I have stated that colour negative is inherently capable of greater colour accuracy than reversal film. In all colour film there is a mismatch between the spectral sensitivity of the light-sensitive layers and the spectral absorption of the corresponding dyes. In colour negative film this is compensated for by the two masks.

Though colour reversal film cannot be masked in the same way as negative film without creating a colour cast, the absence of the masks can be catered for to some extent by digital post-processing if required. This is not the same as profiling using a target - it needs more than that. Even film designed solely for scanning (ie film that cannot be printed optically with any degree of colour accuracy) benefits from some degree of masking via coloured colour couplers despite the use of dedicated digital post-processing.

All this aside, we do what we are happiest with while being curious about what everyone else does.

Best,
Helen

[Oren Grad]

For most work I do a variation of the EK telecine setup process that I am familiar with: ie I shoot a three-step card (Kodak 'Gray Card Plus' or the recent Macbeth card - both being black, grey and white) and balance the three by adjusting the curves, then I use that as the basis for all other scans in that lighting condition and exposure for that film, after setting the black and white points using the film DMax and DMin. This takes care of the uniform combination of masks and dye imperfections. The key thing is that the connection is made between the lighting in the scene and the scan before I then go and do whatever I feel like doing.

Thanks, Helen. That gives me some new ideas to work with. The objective in this case is to integrate the scan into a workflow that manages color consistently between scanner, screen and printer. Concordance with the real world is a separate issue, which I deal with (or not) in other ways.

[Sal Santamaura]

Actually- of all places - I'd probably recommend Ansel Adams' book The Negative for some of this info...

Why "of all places?" It's always been one of the best places for solid technical black and white film information translated into terms that anyone willing to read and think can understand.

...all the comments on this thread - very useful, and revealing of the immense differences not just between digital and film, but between b&w and colour...

Not to mention between the perceptions of different humans.

[roteague]

Why "of all places?" It's always been one of the best places for solid technical black and white film information translated into terms that anyone willing to read and think can understand.

Perhaps. I found the book boring.