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16mm bw vs color film in terms of sharpness


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#1 Roland Mathias

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Posted 06 January 2015 - 04:09 PM

I can't find a lot of good material online shot in Super 16 and with bw film, but I was wondering if currently available 16mm bw film has more sharpness and finer grain

then color 16mm film.

 

thanks


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#2 Robert Houllahan

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Posted 06 January 2015 - 04:21 PM

Possibly the slow speed Orwo UN54 stock.


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#3 Bill DiPietra

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Posted 07 January 2015 - 05:10 AM

Possibly the slow speed Orwo UN54 stock.


Sorry, Rob but I found the slow-speed Orwo stock just as grainy as 7222 when I tested it.
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#4 Robert Houllahan

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Posted 07 January 2015 - 11:14 AM

Well it's certainly no XX31 which if I remember correctly had the highest lp/mm numbers of any Kodak stock including 50D


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#5 Roland Mathias

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Posted 07 January 2015 - 11:38 AM

thanks for the info. I once read that black and white stock is inherently more sharper, due to only using one layer of emulsion. Would you say that the Kodak 7222 while just as grainy

as the Orwo, still a little sharper than the Kodak color stock?


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#6 Dirk DeJonghe

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Posted 07 January 2015 - 12:39 PM

Color negative is far sharper than B&W negative. Plus-X has some 'snap' probably due to edge effect. Double-X or Orwo don't have that. We don't see much Plus-X anymore, but when some comes out of the processing, it really stands out among the Double-X and Orwo. 

B&W negative is a different medium from color negative, just like water colors are different from oil colors and a digital photo is different from a pencil drawing.


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#7 David Cunningham

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Posted 07 January 2015 - 02:11 PM

I have always found the B&W films such as Tri-x and Double-X to be sharper, but grainer.  So, that's distracting and might lead one to not see it as "sharp" because it makes the resolution appear lower.  Color films definitely have a "softer" look to them and color reversal that "softest" of them all.  But yet color reversal will forever be my favorite.  Go figure.  :)


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#8 Mark Dunn

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Posted 07 January 2015 - 02:14 PM

When Kodak developed T-grain technology in the 80s it was generally used to develop new stocks, not reformulate old ones. There were T-grain mono stocks but they were never packaged for cine. So we're stuck withthe existing stocks. With the decline of film here's no prospect of a change.


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#9 David Cunningham

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Posted 07 January 2015 - 02:18 PM

That was exactly going to be my next comment... the primary reason B&W stocks these days are not superior in pretty much any area to color stocks is because no one has developed a truly new B&W stock (or at least not an improved one) in probably 30+ years.  That's part of why "The Artist", a B&W silent film, shot on Kodak Vision3 color negative and then desaturated in post.  They wanted it to have a fine grain look with an organic film look, feel and softness (so they shot film), but they did not want to deal with the heavy grain, lack of latitude and just overall PITA is can be to work with B&W film on a major motion picture (so they shot color film and desaturated in post).


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#10 Josh Gladstone

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Posted 07 January 2015 - 04:46 PM

Yeah, I always did wonder why they never made any T-Max films for cinema.


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#11 John E Clark

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Posted 07 January 2015 - 06:43 PM

Yeah, I always did wonder why they never made any T-Max films for cinema.

 

For stills, by the time Kodak came out with T-Max... I had switched to Fuji Neopan, and Fuji Color(which I still have a number of rolls in the refrigerator... been there for 10+ years... no... I don't clean out the refrigerator frequently...)... so it didn't matter to me what Kodak did.

 

I think the lack of B&W motion picture film 'non' development from the late 60's on, is pretty obvious... few major motion picture projects, only 'highspeed' industrial photography applications, etc.

 

Just an odd thought... when did NFL Films switch to color film?


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#12 Dennis Couzin

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Posted 07 January 2015 - 06:55 PM

Color negative is far sharper than B&W negative. Plus-X has some 'snap' probably due to edge effect. ...

 

I have to agree with Dirk on this.  Flip through Kodak data sheets and compare the MTF curves for color negative and B&W negative stocks with similar EI.  MTF out to 60 c/mm is a common criterion for sharpness for 16mm films.  For the color stocks there are separate MTF curves for the three layers.  I believe it is fair to weight the curves 26%, 64%, 10% for the red sensitive, green sensitive, and blue sensitive layers respectively. Vision2 100T color negative bests Plus-X negative in this comparison.  I was surprised by this, and don't know the explanation.

 

The MTFs that Kodak measures include development-adjacency effects, evidenced by MTF values over 100%, and those of the color negative films are at least as great as Plux-X's and Double-X's. 

 

The red sensitive layer shows low MTF at least in part because it is buried under the other layers and the test exposure is at the "image plane" probably the film front surface.  The distance of the red senstive layer from the front further weakens the net MTF during contact printing.  But optical printing can focus inside the emulsion pack (see here).


Edited by Dennis Couzin, 07 January 2015 - 06:59 PM.

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#13 Dennis Couzin

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Posted 07 January 2015 - 10:18 PM

Small correction to just previous post.  Better to weight the curves 23%, 69%, 8% (R, G, B respectively).


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#14 Simon Wyss

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Posted 08 January 2015 - 12:26 AM

Films aren’t sharp, the picture is sometimes. I think everybody wants to speak about resolving power and or acutance. The expression sharpness has to do with the focus. Optics

 

Sorry if I sound like an old school teacher.


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#15 Dennis Couzin

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Posted 08 January 2015 - 08:05 AM

thanks for the info. I once read that black and white stock is inherently more sharper, due to only using one layer of emulsion. ...

 

No. No.  It's not that simple.  Film unsharpness is largely due to photons bouncing around in emulsions before they reach the grain where they make latent image.  So emulsion thickness is the major sharpness factor rather than emulsion count.  (Also realize that even B&W emulsions are multilayer, but let's ignore this so as not to overly complicate the explanation.)  Each of the three emulsions for color films can be much thinner than B&W emulsions producing similar density because the former make density from dyes produced in proportion to developed silver while the latter make density from developed silver itself.  That proportion can be high, so the undeveloped color film emulsion need not contain much silver halide, and thus be thinner.  You didn't think color film stock contained 3× as much silver as B&W film stock, did you? 

 

The sum of the separate color-sensitive emulsion thickesses of color film stocks is comparable to the emulsion thickness of B&W film stocks.  In the color films it's the photons that will expose the red sensitive layer, in the bottom position, that suffer the worst diffusion.  So the MTF for the red sensitive layer is by far the worst of the three in the color film and generally worse than for a B&W film of similar EI.  Since red light contributes significantly (like 23%) to luminance in the final (projected) image, that unsharp red sensitive layer in the original film is a defect in tri-layer color film design.  For color print films, which can be much slower, the design is different, with the red sensitive layer on top, followed by the green sensitive layer, and the blue sensitive layer which will hardly contribute to final luminance on the bottom.  (Unhappy mnemonic: when you hand clean a color print your cloth picks up some cyan color, whearas when you hand clean a color original your cloth picks up some yellow color.)  Unfortunately that optically improved design was impossible for faster color films.


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#16 Dennis Couzin

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Posted 08 January 2015 - 08:18 AM

Films aren’t sharp, the picture is sometimes. I think everybody wants to speak about resolving power and or acutance. The expression sharpness has to do with the focus. Optics

 

Sorry if I sound like an old school teacher.

You don't look like such an old school teacher to predate MTF -- Otto Schade's work of the1950s.

 

The general motive behind measuring film MTF is that it can be combined, by simple multiplication, with lens MTF.  Development adjacency effects somewhat complicate matters, but with MTF we have a single concept underlying sharpness, acutance, resolving power, etc. for both lens and film.


Edited by Dennis Couzin, 08 January 2015 - 08:19 AM.

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#17 Simon Wyss

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Posted 08 January 2015 - 01:39 PM

Sharpness is entirely wrong placed with Modulation Transfer Function, too.

 

Now I’m no longer sorry. The image is sharp or out of focus, the film cannot be unsharp or very sharp or anything.


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#18 John E Clark

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Posted 08 January 2015 - 01:49 PM

Sharpness is entirely wrong placed with Modulation Transfer Function, too.

 

Now I’m no longer sorry. The image is sharp or out of focus, the film cannot be unsharp or very sharp or anything.

 

I'm not so pedantic when I read 'sharpness', but interpret that to mean the image apparent 'sharpness' to the human observer.

 

MTF may set a limit on how well a film will record an 'edge', which for humans is significant in the evaluation of 'sharp'.

 

And obviously, an image 'in focus' is more 'sharp', that is edge information is recorded with higher fidelity, than one which is not.

 

Lens characteristics of course play into how 'sharp' an image may be, or appear to be, which of course are not factored into a film stock's listed MTF...

 

The often used 'unsharp mask' filter really does not 'add' sharpness but contrast to edges, but the human observer considers the result to be 'sharper' than the unfiltered image.

(Well, until edge 'ringing' becomes visible...).

 

The net result is that an image that has higher contrast, may be 'evaluated' as sharper than an image using a medium which has a higher MTF, but lower contrast.


Edited by John E Clark, 08 January 2015 - 01:50 PM.

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#19 Dennis Couzin

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Posted 08 January 2015 - 02:44 PM

Sharpness is entirely wrong placed with Modulation Transfer Function, too.

 

Now I’m no longer sorry. The image is sharp or out of focus, the film cannot be unsharp or very sharp or anything.

 

Expressions like "film sharpness" which launched this strand have an accepted use.  Here is Papa Kodak's language in its Vision3 data sheet:

 

Modulation Transfer Function
The "perceived" sharpness of any film depends on various
components of the motion picture production system. The
camera and projector lenses and film printers, among other
factors, all play a role. But the specific sharpness of a film
can be measured and is charted in the Modulation Transfer
Function Curve.

 

For lenses, for incoherent imaging, the MTF contains all the information needed to derive sharpness, acutance, resolving power, etc.  For film there are the two complications that the image is noisy (grainy) and that there are development adjacency effects in addition to the underlying optical MTF.  Nevertheless "sharpness" derived from the film MTF in the same way it is derived from the lens MTF is meaningful. 

 

Unless you have a serious theory to offer in replacement, why carp at the other guy's semantics?


Edited by Dennis Couzin, 08 January 2015 - 02:45 PM.

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#20 Mark Dunn

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Posted 08 January 2015 - 02:58 PM

 

only 'highspeed' industrial photography applications, etc.

 

 

High speed cine went to VNF  when it came in in the 70s. ironically, when VNF was discontinued in 2004, some industrial users went back to b/w neg.

When David Lynch made 'The Elephant Man' in 1980. Freddie Francis found to his dismay that hardly anyone still knew how to process b/w properly. Some scenes still have uneven density.


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