Help understanding terms - Tonality vs Contrast.

cliveh · Jun 18, 2021

wiltw said:
Indeed. Back in the 'old days' when we spoke of using the same emulsion in both 135 and in Medium Format, 'tonality' was said to be better on the medium format shot, simply because (linearly) there were twice as many film grains across the (about) 2x longer film capture area which captured the same scene. So in the negative the transitions of tonality were spread out across more film grains, with better spatial spreading of the transitions in tone which occurred across the subject, so medium format allowed better capture of those transitions. That is, "how smoothly gradual transitions between light are portrayed on film."

I would dispute this statement, as the tonality is determined by the original lighting conditions, development and printing contrast and has nothing to do with the number of film grains.

wiltw · Jun 18, 2021

cliveh said:
I would dispute this statement, as the tonality is determined by the original lighting conditions, development and printing contrast and has nothing to do with the number of film grains.

Then you are disputing what was commonly stated as the advantages of medium format shooting over 135 format

Grain size advantage for same size print
Better tonality transitions and better color gradation transition because of greater number of grains/color clouds

Even today that same mantra is stated. Taken from B&H Photo web pages
https://www.bhphotovideo.com/explor...d-solutions/explaining-the-medium-format-look
although their article is stated in the context of digital pixels rather than film grains, but the same conceptual advantages applies.

"Color and Tonality
The two other chief signifiers of a medium format (in addition to 'sharpness' and 'resolution') ook are color and tonality, along with how they affect dynamic range. While separated here for discussion, it’s worth mentioning that color and tonality are also consequences of the larger pixel sizes afforded by the larger sensor size but are maybe the most perceivable benefits of the sensor’s design. Just as a higher resolution in pixels is expected with medium format, so is a greater bit depth. Whereas smaller format cameras tend to be 12-bit, maybe 14-bit, medium format cameras will usually begin at 14-bit, and some have higher 16-bit capabilities. Beyond just these numbers, the cameras can, again, make use of the larger photosite sizes to record more information and make use of this higher bit depth to achieve more exacting colors and, subsequently, smoother transitions from color to color.
"More than just color accuracy, this also translates to tonality and contrast, and explains the smoother rendering and gradient from a highlight area to a shadowy area. And this is where dynamic range is factored in; it’s a bit of a misnomer that medium format cameras have an objectively wider dynamic range than smaller format cameras. Especially compared to some of the new full-frame flagships coming out, medium format cameras may have a smaller overall range when measured in stops. However, the smoothness in transition from tone to tone (or stop to stop, or zone to zone, if you want) is what separates medium format cameras (no pun intended) from their smaller counterparts. This is one of those indescribable points of contention when talking about a medium format look, but the smoothness and natural look of a gradient from extreme tones can be a key tell for the larger sensor size."

In the context of film, I quote from The Darkroom:
https://thedarkroom.com/35mm-vs-medium-format-film-comparison/

"120 Medium Format
Once the most widely used film size, 120 medium format film now occupies a niche in the photography world, adored by professionals and amateurs alike for its distinctive, true-to-life quality.
The primary distinction of medium format film is the larger size. This size difference can be anywhere from two to six times larger than 35mm films. This larger film size produces images with much more resolution, allowing the photographer to create large prints without the noticeable grain that you would get with smaller format film. The larger size of medium format film also allows for more control over depth of field, and therefore has greater creative potential.
Aside from its size, there are other, more subtle advantages to shooting medium format film. Because the tonality is better (smoother gradations) and lack of perspective distortion, medium format images have a distinct feel that is instantly recognizable. This lack of perspective distortion, which warps and transforms an object significantly from how it looks with a normal focal length, medium format images tend to look closer to what your eyes see in the real world. This natural look is what makes medium format images so powerful."

And then in general discussions for photo forms,
https://www.photo.net/discuss/threads/medium-format-vs-35mm-film-tonality.225751/

"The tonality smoothness is the biggest benefit of MF over 35mm, and LF is a whole level higher yet. A lot of people are under the misimpression that "sharpness" is the biggest benefit to be gained by jumping up a format size. Not so: It's tonality. If you look at the LPM figures for assorted lenses, there are actually 35mm lenses that can resolve detail nearly as well or better than some common MF and LF rigs, but film grain and the need for greater enlargement prevents that resolution from ever approaching the clarity of even a relatively low grade MF or LF lens."

One last discussion...
https://fstoppers.com/originals/medium-format-look-real-or-hoax-395685

"Tonality is the big one that photographers seem to forget about, and yet it is the greatest strength of larger formats. Because the frame is larger, there is more space to make a tonal transition than on 35mm. Therefore, the transition can be smoother. Period. The larger the format, the better the tonality can potentially be. That's not my opinion. That's science. Think about it this way: You have to go from white to black within 2 inches. Now, make the same transition from white to black within 6 inches. You can place more tones in 6 inches than in 2. It's that simple. This greater space for tonal changes creates truer, more lifelike images."

gone · Jun 19, 2021

The only way to understand the difference between tonality and contrast is to look at the prints. It's a visual thing. It has nothing to do w/ the whys and wherefores, it has to do w/ what the photographer wants to do in this regard. Go for more contrast, or go for more tonality, and normally this is decided by the choice of film, lens filters, how it's exposed, and the choice of developers. I honestly don't know why this would be a mystery to anyone.

cliveh · Jun 19, 2021

wiltw said:
Then you are disputing what was commonly stated as the advantages of medium format shooting over 135 format

I stand corrected and agree the number of film grains does effect tonality and I should have given more thought to my post. However original lighting conditions, development and printing contrast also have a major effect on tonality.

Bill Burk · Jun 19, 2021

I might say I was describing local contrast vs overall contrast.

wiltw · Jun 19, 2021

cliveh said:
I stand corrected and agree the number of film grains does effect tonality and I should have given more thought to my post. However original lighting conditions, development and printing contrast also have a major effect on tonality.

Cliveh, I do not think that previously you were wrong about talking about Lighting, but you did err with regard to film contribution, and format size contribution, to the tonality of the Capture. Just as both Lens and Film (or Sensor) contribute to resolution, too many forget the ultimate contribution of the optics and pay attention only to pixel count on sensor.
One very often does use lighting to alter the dynamic range and contrast of the scene content, so it can be captured within the limits of the film or it can later be recreated within the tighter limits of the offset press. But that does not alter the fundamental ability to capture and portray the transition in tonality in medium format vs 135 frame.
Two different aspects of Tonality...the scene content, and the capture media

warden · Jun 19, 2021

wiltw said:
Two different aspects of Tonality...the scene content, and the capture media

And a third aspect would be the output size, yes? I mean, if I use fine grained film and a medium format negative to print a 7X7" image on paper, and also use a 35mm negative to print the same scene at the same 7X7" size, I don't think I'll see any difference in tonality between the two.

wiltw · Jun 19, 2021

warden said:
And a third aspect would be the output size, yes? I mean, if I use fine grained film and a medium format negative to print a 7X7" image on paper, and also use a 35mm negative to print the same scene at the same 7X7" size, I don't think I'll see any difference in tonality between the two.

No challenge to that observation. I already mentioned how offset press limits tonality and contrast, so output media is a consideration. But given the fact that most of the time the negative is blown up to print size, the neg is most often the most limiting factor rather than the print being the limit.

Nicholas Lindan · Jun 19, 2021

I'll advance a simplistic description:

Contrast is the transfer function from scene luminance to print luminance. The transfer function incorporates camera flare, film HD, enlarger flare and paper HD;
Tonality is the aesthetic suitability of the transfer function to that particular image. Although subjective there is usually a consensus opinion;
Film grain plays a part in contrast and aesthetic tonality.

warden · Jun 19, 2021

warden said:
And a third aspect would be the output size, yes? I mean, if I use fine grained film and a medium format negative to print a 7X7" image on paper, and also use a 35mm negative to print the same scene at the same 7X7" size, I don't think I'll see any difference in tonality between the two.

wiltw said:
No challenge to that observation. I already mentioned how offset press limits tonality and contrast, so output media is a consideration. But given the fact that most of the time the negative is blown up to print size, the neg is most often the most imiting factor rather than the print being the limit.

Now I'm talking myself out of my own line of thinking.

In front of the camera is a perfect gradient, left to right, from white to black. Capture that gradient with a fine grained film in 35mm and also a 6x9 MF camera, perfectly exposed. Print each to 24" on the wide side, stand back at a normal viewing distance for that size of print, and compare with the naked eye. My guess? Each print would show a graduation of values so fine that the human eye couldn't differentiate one value from the smooth transition to the next (see Ctien's article on our limits from earlier) but the print from the 35mm negative would do it with more grain. Same "tonality" but different resolution.

wiltw · Jun 19, 2021

warden said:
Now I'm talking myself out of my own line of thinking.

In front of the camera is a perfect gradient, left to right, from white to black. Capture that gradient with a fine grained film in 35mm and also a 6x9 MF camera, perfectly exposed. Print each to 24" on the wide side, stand back at a normal viewing distance for that size of print, and compare with the naked eye. My guess? Each print would show a graduation of values so fine that the human eye couldn't differentiate one value from the smooth transition to the next (see Ctien's article on our limits from earlier) but the print from the 35mm negative would do it with more grain. Same "tonality" but different resolution.

Let me present it this way..

subject is a continuous range of tones from dark gray thru almost white.
That subject fills a 36mm frame or a 56mm frame.
The medium format neg has 1.55x the linear distance to capture the tonal gradient of the subject, and in that space 1.55x the grains, so it has 1.55x better reproduction of the tonal gradient of the subject (actually, 2.4x, since tones are really 2D, not 1D)

The two negs are printed to 24" wide. The tonallty from the neg is transfered to the print, with the better tonality of MF being transferred to the print. The small neg is more limiting because its tonal transfer is more limited. Furthermore, the 135 neg grain is very apparent at 25.4x magnification, while the MF neg was magnified only 10.9x. The more visible grain further detracts from the subject impression of tonality on the print, unless you are viewing so far back that the eye cannot perceive grain size on either print...but even then the better tonality of the MF neg can be perceived.

warden · Jun 19, 2021

wiltw said:
Let me present it this way..

subject is a continuous range of tones from dark gray thru almost white.

That subject fills a 36mm frame or a 56mm frame.

The medium format neg has 1.55x the linear distance to capture the tonal gradient of the subject, and in that space 1.55x the grains, so it has 1.55x better reproduction of the tonal gradient of the subject (actually, 2.4x, since tones are really 2D, not 1D)

The two negs are printed to 24" wide. The tonallty from the neg is transfered to the print, with the better tonality of MF being transferred to the print. The small neg is more limiting because its tonal transfer is more limited. Furthermore, the 135 neg grain is very apparent at 25.4x magnification, while the MF neg was magnified only 10.9x. The more visible grain further detracts from the subject impression of tonality on the print, unless you are viewing so far back that the eye cannot perceive grain size on either print...but even then the better tonality of the MF neg can be perceived.

It would be fun to try the experiment. What I'm thinking is that if the print from 35mm, grain and all, accurately hits all the values that the eye can perceive, smoothly, as in Ctien's article, then the MF print is no better except for the lack of grain (resolution) to a human eye at normal subject difference. Now if you measure with something better than the human eye or pixel peep then the MF or large format print would be far smoother of course.

Taken to a ridiculous extreme, a 24" print of that range of tones from a Minox (!) next to a 24" contact print from an ultra large format camera would be a no-brainer. But in my small print world 35mm and MF are "the same tonality".

wiltw · Jun 19, 2021

warden said:
It would be fun to try the experiment. What I'm thinking is that if the print from 35mm, grain and all, accurately hits all the values that the eye can perceive, smoothly, as in Ctien's article, then the MF print is no better except for the lack of grain (resolution) to a human eye at normal subject difference. Now if you measure with something better than the human eye or pixel peep then the MF or large format print would be far smoother of course.

Taken to a ridiculous extreme, a 24" print of that range of tones from a Minox (!) next to a 24" contact print from an ultra large format camera would be a no-brainer. But in my small print world 35mm and MF are "the same tonality".

If you start with the understanding that the distance between grains is the same for 135 as for MF, assuming the same emulsion type, and you magnify one by 25x and the other by 11x, the spaces between the grains in the 24" print will be 2.3x greater in the print from the 135 neg! Empty SPACES BETWEEN the grains that conveys tonal definition! and the grains themselves are 2.3x more apparent to the eye.. White space vs. black grain...less able to fool your brain about continuity, just like a photo in newsprint vs. a photo in National Geographic, due to the dots per inch of ink.

cliveh · Jun 19, 2021

At the end of the day, Large format photography is not better than 35mm photography, just different.

wiltw · Jun 19, 2021

cliveh said:
At the end of the day, Large format photography is not better than 35mm photography, just different.

Tell that one to the magazine that, for many decades, used to refuse all photos not taken on Large Format transparency, because smaller formats failed to meet their quality standards!
Several still have the requirement of large format:

"The Historic American Buildings Survey (HABS), the Historic American Engineering Record (HAER), and the Historic American Landscapes Survey (HALS) require large format film-based photography. 4×5", 5×7", and 8×10" large format film formats are the only acceptable formats for inclusion in these collections at the Library of Congress. 4x5 and 5x7 are generally used in the field (5×7" is preferred for very significant buildings) and 8×10" is generally utilized for photo-duplication of historic photographs, documents and blueprints."

cliveh · Jun 19, 2021

Quality in terms of context or image quality? I would suggest that context wins every time.

BradS · Jun 19, 2021

cliveh said:
At the end of the day, Large format photography is not better than 35mm photography, just different.

depends upon what is meant by "better"

warden · Jun 19, 2021

wiltw said:
Empty SPACES BETWEEN the grains that conveys tonal definition! .

That's why I offered the Minox vs contact print example. I know they're different in resolution. Resolution is a good thing. ;-)

Help understanding terms - Tonality vs Contrast.

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