The Maths of a Fine B&W Print

We're getting way off topic here, but...

http://www.europhysicsnews.com/full/34/article5.pdf

Note that the excerpt from Arrhenius' speech you quote mentions

A third group of studies, for which in particular Einstein has received the Nobel Prize..

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That's the Photoelectric Effect he was talking about, not relativity!

In the first paragraph he mentions relativity, but in context with "discussion", "lively debate", and "rigorously examined".

I think it is time to consider if, being humble and trying to
understand what the other posters are trying to communicate,
possibly could change this thread to the better.

I believe not so much good coming out of stubbornly defending
ones own point, not listening to the counterpart or even wildly
doing all to prove the counterpart wrong or puting him in bad
light.

Thanks in advance,

Jan Johansson

Bearing in mind that the OP has only posted once on APUG and that in sixteen pages of this heated thread has not commented on any of the points made, or asked for elaboration or clarification, I'd have to say...


:rolleyes:

It appears that Jed is neglecting a science here, in that he believes that print quality is solely a matter of physics, and neglects the insights of psychology on how the brain processes patterns and reacts to changes in light.

FrankB said:

Bearing in mind that the OP has only posted once on APUG and that in sixteen pages of this heated thread has not commented on any of the points made, or asked for elaboration or clarification, I'd have to say...

Fol-de-rol!​

:rolleyes:

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Frank and others of this opinion;

I think that we have tried to answer the OP. The OP asked if there were maths for defining a fine B&W print.

The answer was conflicting in that one person felt there was and it was MTF, whereas the others said there was not and gave all of the reasons. We have suggested that math is a poor way to describe a fine print.

I put forth the statement that Information Content was sometimes used, but it too is fraught with controversy.

As we go back and forth, we see that there is a general consensus that photography is so much art that it is almost impossible to quantify.

This is an attempt to remove the obfuscation and opinion, but even this has a flavor of my own feelings in the matter, nowithstanding it expresses a flavor of the majority, I think.

I think that answers the OP as best we can under the circumstances.

PE

DBP said:

It appears that Jed is neglecting a science here, in that he believes that print quality is solely a matter of physics, and neglects the insights of psychology on how the brain processes patterns and reacts to changes in light.

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In this thread I mentioned psychophysics ( nowadays often part of physics). In all research referenced in this thread, ( German, Swedish and US), the central issue were the properties of the human eye, and all research has been done with panels. The research makes a link between the human perception (including MTF of the human eye) and instrumental ( lenses etc.) properties. Therefore, the human side is part of the studies. The result of these studies indicate a correlation between image quality and the properties of the human eye and the physical properties of lenses etc. As an answer to the original question I refer to the results of these studies. Also, because I have used these studies succesfully in real photography. Apparently, not everyone will accept the results of these studies. But I have not seen, why.

Jed

My point was that there is much to be considered, and even more still to be learned, about what the brain does with the image data coming in from the optic nerves, and then in turn how that relates to the aesthetic appreciation of the print. Included in that question is how the growth of brain function during human development may be affected by exposure to photographic images and how that in turn may influence later perceptions. These are fundamentally questions of cognitive psychology.

DBP said:

My point was that there is much to be considered, and even more still to be learned, about what the brain does with the image data coming in from the optic nerves, and then in turn how that relates to the aesthetic appreciation of the print. Included in that question is how the growth of brain function during human development may be affected by exposure to photographic images and how that in turn may influence later perceptions. These are fundamentally questions of cognitive psychology.

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You are presumably familiar with the research indicating that excessive exposure to television -- apparently, ANY at a very early age -- contributes to attention deficit disorder? The way the brain is 'wired' for speech is fascinating: the Japanese L/R is famous, but less well known are the ways that English-speakers have problems with sounds such as 'da' and 'dha' or 'ka' and 'kha' in Sanskrit or Tibetan, or the 'q' in Maltese -- qaqocc, artichoke, dqiq, flour, never mind the Bushman 'click' languages of which I know not a single word.

My own belief is that similar considerations apply to ALL perception, including all visual arts.


Cheers,

R.

Roger Hicks said:

You are presumably familiar with the research indicating that excessive exposure to television -- apparently, ANY at a very early age -- contributes to attention deficit disorder? The way the brain is 'wired' for speech is fascinating: the Japanese L/R is famous, but less well known are the ways that English-speakers have problems with sounds such as 'da' and 'dha' or 'ka' and 'kha' in Sanskrit or Tibetan, or the 'q' in Maltese -- qaqocc, artichoke, dqiq, flour, never mind the Bushman 'click' languages of which I know not a single word.

My own belief is that similar considerations apply to ALL perception, including all visual arts.


Cheers,

R.

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My undergraduate degree is in psychology, with one of my primary areas of interest being psycholinguistics. Given the general tendency of the brain to optimize for the environment encountered in formative years, of which language is a good, but by no means solitary example, it is reasonable to presume similar effects on the visual arts. There are a number of lovely articles on the subject in a book by the late Harold Klawans, MD, entitled Why Michael Couldn't Hit .

I should also note that most measures of human perception show appreciation of amplitude to be non-linear, as in the use of the decibel logarithmic scale for auditory amplitude.

DBP said:

My undergraduate degree is in psychology, with one of my primary areas of interest being psycholinguistics. Given the general tendency of the brain to optimize for the environment encountered in formative years, of which language is a good, but by no means solitary example, it is reasonable to presume similar effects on the visual arts. There are a number of lovely articles on the subject in a book by the late Harold Klawans, MD, entitled Why Michael Couldn't Hit .

I should also note that most measures of human perception show appreciation of amplitude to be non-linear, as in the use of the decibel logarithmic scale for auditory amplitude.

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Thanks. I shall look for the book.

And of course an example of non-linearity is photo prints: we can fairly easily see density variations of 0.01 in the highlights, but 0.10 in the shadows is rather harder to see.

I did not mean for a moment to belittle your expertise, or to suggest that you did not know the above; it was just an easy way of introducing it into the conversation, about a subject where you are clearly more knowledgeable than I.

Cheers,

R.

Roger;

By definition, the human eye has been defined by some as being linear even though we know it is not, but being part of the process, the slope of the eye to exposure vs density is defined as 1.0. The eye then adapts beyond this to low and high light levels but is still assumed to be linear.

This assumption is inherent in the derivation of all H&D curves AFAIK.

PE

Roger Hicks said:

Thanks. I shall look for the book.

And of course an example of non-linearity is photo prints: we can fairly easily see density variations of 0.01 in the highlights, but 0.10 in the shadows is rather harder to see.

I did not mean for a moment to belittle your expertise, or to suggest that you did not know the above; it was just an easy way of introducing it into the conversation, about a subject where you are clearly more knowledgeable than I.

Cheers,

R.

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I did not feel belittled in the least, just thought I would explain why I introduced what little expertise I can claim in the area. As my current field is in no way related, I have not really kept current, except through the popular literature. I actually hesitated for a day to see if we had an expert in the psychology or neurology of perception who was willing to jump in. Given the APUG membership, I thought it was reasonably probable that someone current in the field would show up. I know a great deal has been learned over the last two decades due to the introduction of brain imaging technology.

Longing for certainty

I think the quote from Lord Kelvin in this post from Monophoto has great relevance to this discussion:

(there was a url link here which no longer exists)

IMHO many of us long to be able to measure things - to be able to specify things with exactitude, and compare two different items/prints/films/processes and identify, with certainty, the one that is best/finest/sharpest/coolest/warmest etc..

It is normal to want to be able to make a simple argument, and succeed without question.

Of course, it is much more interesting when we can't.

Matt

P.S. thanks Monophoto, that was just what I was looking for!

that is a great quote Matt and Mono, but photography is not only science

DBP said:

I did not feel belittled in the least.

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Ah, good. The trouble with the internet (even APUG) is that it is so easy to give inadvertent offence.

I always liked the definition of a gentleman as someone who is never unintentionally rude.

Cheers,

R.

PE - Thank you for the taking the time and trouble to condense and clarify the thread. It was courteous of you and I do appreciate it.

However, I do still think that the original poster was a troll (fol-de-rol!) who has had the effect he/she intended. If the thread can be salvaged (as appears to be happening) and a enjoyable exchange of views had, well then that's one up for APUG!

To address the original question, my view (like many others) would be that using maths to explain the depth of a traditional B&W print would be a poor substitute for showing some traditional B&W prints.

Best regards,

Frank

I am reminded of an aside by the late Lipman Bers, my college calculus professor, to the effect that, being tone deaf, he didn't understand why music was beautiful until he saw the equations.

Math and music.

DBP said:

I am reminded of an aside by the late Lipman Bers, my college calculus professor, to the effect that, being tone deaf, he didn't understand why music was beautiful until he saw the equations.

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Strangely enough, I have known a number of skilled professional musicians who are mathematically inclined and at least one who earns his living as a mathematician.

Most of the human responses are best plotted as just noticable differences vs stimulus. This leads to plots that are more or less linear on log-log paper. That is why we use density as log (incident/transmitted).

When I converted from aeronautical engineer to human factors study at NASA, I had to take a couple of psychology courses at William and Mary, and I had a mentor at NASA who was a psychologist. The eye only uses smooth movements when it is tracking a moving object. Reading of instruments of aircraft and of printed material are done by saccadic movements. While the center of attention is changing from one point to another, the eye is blind. We designed and used apparatus for measuring eye movements. We could prove that the subject was blind to anything that happened between look points. When you examine a photograph, you do it with saccadic eye movements. While the eye is fixed on a particular point, the peripheral vision can provide some information, but the acuity falls off so rapidly away from the fixation point that a digital altimeter scale cannot be read when it is only a few degrees from the fixation point. Yet we integrate the information from these many fixation points to get a mental image of the picture. This ability can fool one into thinking that the image is also accurate for changing information. The typical altimeter when I was working had a digital drum to indicate 1000's and a needle like a clock dial to indicate hundreds. A flight was almost lost one time (and maybe others) when the airplane was descending at a rate such that the needle made a complete revolution between looks. The pilot did not attend closely enough to see that the drum showed 1000 feet decrease. Visibility was too poor to get the clue from the window. This is part of the psycophysical aspect of vision. Sleight of hand experts use this aspect to make you look at one hand while the other is doing something he doesn't want you to see.