Acros II - What speed are you getting?

[faberryman]

No. Apart from blowing off an entire field of science offhand, it is considered an opinion because you have no evidence to substantiate it. It is impossible to have confidence the claims are true. Which is fine when working in your own closed system; but how am I supposed to know that your observation of ISO film speed not being applicable to real world situations is correct or that it isn’t just your metering technique?

The 90s and early 2000s say a good deal of people using the Zone System. What came with it was an explosion of Dunning-Kruger incidence as people were only familiar with Zone System testing and how it obtains personal film speeds by incorporating how “real world” testing and compensates for their tools. As we know Zone System testing and ISO testing are two different methodologies and produce different results in identical conditions. Being unaware of the difference between the two methods, a meme arose that Zone System testing results were the true film speed. Conspiracy theories soon followed that film manufacturers fudged their results, and that lab testing doesn’t represent real world testing. Nobody noticed that their personal speeds all were effectively the same and differed to the same degree from the ISO speeds.

Back in the heyday of Fred Picker and Zone VI Workshop, you could do the film speed test at home and send in your negatives, and Fred would mark which negative had the correct film base plus fog density. I did so around 1974. My personal speed index for Tri-X in HC110 1:31 was 320. Everybody used Tri-X and HC110 back then because we were assured that with that combination our prints from 35mm would magically look the same as prints from 4x5. After you got over your naivete, you would buy a 4x5 camera. Anyway, Fred said he had seen personal speed indices from 100-600, which I had a hard time believing. You must have been doing something pretty funky to get 100 or 600 with Tri-X.

This is the first I have heard of a conspiracy among film manufacturers to inflate their ISO ratings. Why would you lead your customers to underexpose your film. That doesn't sound like a very good marketing strategy.

The real challenge isn't arriving at a correct personal film speed; it is consistently placing the important areas of your scene in the correct zones.

 

[chuckroast]

Apart from blowing off an entire field of science offhand, it is considered an opinion because you have no evidence to substantiate it. It is impossible to have confidence the claims are true. Which is fine when working within your own closed system; but how am I supposed to know that your observation of ISO film speed not being applicable to real world situations is correct or that it isn’t just your metering technique?

First of all, I haven't "blown off" anything. I've described the ISO standard for what it is - a way to consistently define film light sensitivity across manufacturers and film types.

If you look upthread you will discover that I am more than versed in research methods, have spent some time doing them myself. But that's not what I entered into discussion here, nor did I ever claim it was. I am describing how I work and providing examples. I am utterly indifferent to meeting some academic definition of measurement to satisfy internet pedantry. If you don't like the outcomes you see, that's fine with me, but other curious minds wanted to see examples of how I was working.

The first stage of a lost cause it demanding "citations" or "proof". This isn't a research lab, it's a place sharing practice.

The 90s and early 2000s saw a good deal of people using the Zone System. What came with it was an explosion of Dunning-Kruger cases as people were only familiar with Zone System testing and how it obtains personal film speeds by incorporating “real world” testing. As we know Zone System testing and ISO testing are two different methodologies and produce different results in

Dismissing a whole group of people as "Dunning-Kruger cases" is arrogant and condescending. It smacks of "I'm so smart"-ism and is unnecessarily unkind. I've done plenty of lab work, experimental design, and statistical reductions in my lifetime - well ... enough to realize I didn't like it all that much - and I didn't ever believe it gave me license to be unpleasant to other people.

identical conditions. Being unaware of the difference between the two methods, a meme arose that Zone System testing results
were the true film speed. Conspiracy theories soon followed that film manufacturers fudged their results, and that lab testing doesn’t represent real world testing. Nobody noticed that their personal Zone System speeds were effectively the same and differed to the same degree from the ISO speeds.

So what? The ONLY thing that ultimately matters is the final image. Not whether someone has done a quantum chemical analysis of state changes in silver halide production. There are people for whom this sort of fussy detail matters and for whom doing things like defining ISO standards is part of their daily practice, but it's not what they're doing here.

I repeat, using meters that check to be reasonably accurate, and thermometers that are known to be accurate, and shutters whose errors are known, and consistent water and developer formulations, I never got good shadow detail using ISO speed with any film or developer using standard development practice - ever. And I'm not alone by a long shot.

 

[chuckroast]

Back in the heyday of Fred Picker and Zone VI Workshop, you could do the film speed test at home and send in your negatives, and Fred would mark which negative had the correct film base plus fog density. I did so around 1974. My personal speed index for Tri-X in HC110 1:31 was 320. Everybody used Tri-X and HC110 back then because we were assured that with that combination our prints from 35mm would magically look the same as prints from 4x5. After you got over your naivete, you would buy a 4x5 camera. Anyway, Fred said he had seen personal speed indices from 100-600, which I had a hard time believing. You must have been doing something pretty funky to get 100 or 600 with Tri-X.

It's not all that surprising to me. I've been doing this stuff on- and off for the better part of five decades and the variability across shutters, meters, and even thermometers I've actually seen in person could easily explain that range of results. It's common for the top speed of leaf shutters to be slow by 1/2-1 full stop, even when new ... I've measured as much. it's common for mechnical analog meters to be off a full stop either way. These sorts of things are why we pursue our personal ASA - not because it's some profound truth of the universe dictated by laboratory standards, but rather to bring consistency to our work by accounting for these variabilities.

This is the first I have heard of a conspiracy among film manufacturers to inflate their ISO ratings. Why would you lead your customers to underexpose your film. That doesn't sound like a very good marketing strategy.

I have never heard there was a conspiracy. I have heard it suggested that the manufacturers embraced the ISO definition because it magically doubled film speeds overnight and gave them marketing fodder. However, no one has ever provided evidence to that effect, at least that I've ever seen.

The real challenge isn't arriving at a correct personal film speed; it is consistently placing the important areas of your scene in the correct zones.

I agree that proper placement is the hardest part of this, but without a meaningful baseline personal EI to work from, we're just throwing darts.

 

[faberryman]

These sorts of things are why we pursue our personal ASA - not because it's some profound truth of the universe dictated by laboratory standards, but rather to bring consistency to our work by accounting for these variabilities.

I don't know where this "profound truth of the universe" stuff comes from. Personal film speeds are personal because they take into account personal equipment and personal working methods.

I have never heard there was a conspiracy. I have heard it suggested that the manufacturers embraced the ISO definition because it magically doubled film speeds overnight and gave them marketing fodder. However, no one has ever provided evidence to that effect, at least that I've ever seen.

Film speeds magically doubled overnight in 1960 when the safety factor was eliminated from the ASA standard. The ISO standard was not adopted until 1993. This has been alluded to several times in this thread.

I agree that proper placement is the hardest part of this, but without a meaningful baseline personal EI to work from, we're just throwing darts.

Hence, the need for personal film speed determinations.

 

[MattKing]

I have never heard there was a conspiracy. I have heard it suggested that the manufacturers embraced the ISO definition because it magically doubled film speeds overnight and gave them marketing fodder. However, no one has ever provided evidence to that effect, at least that I've ever seen.

Ah, you are talking about the years when 135 film was considered miniature, SLRs were exotic and rare, and many people wore neckties to do darkroom work.
And, senior citizen me was 4 years old.
Things have changed a bit.

 

[chuckroast]

Ah, you are talking about the years when 135 film was considered miniature, SLRs were exotic and rare, and many people wore neckties to do darkroom work.
And, senior citizen me was 4 years old.
Things have changed a bit.

We are of a similar vintage ... wait, you' DON'T wear a necktie in the darkroom? For shame.

 

[Craig]

It looksto me that you are prioritizing shadow detail over everything else and therefore arrive at a reduction in film speed. To me, all the sample photos you presented look overexposed with blown highlights, which accords with your desire for shadow detail.

Thus your working EI is less than box speed, but I wouldn't say that was universally accepted. I would have exposed the film differently than you prefer, as shadows are generally unimportant to me, I'm more interested in midtones.

 

[DREW WILEY]

Craig - that is exactly why there is no ideal "one shoe size fits all" approach to defining film speed. If one needs deep shadow resolution in a high contrast scene, it's far wiser to pick a film with a longer straight line way down into those shadows, with a minimum of toe, rather than overexposing a medium toe film in order to get that scale up onto the straight line portion, at the expense of shouldering off and blowing out the highlights. Even with the VERY SAME film and developer, I might apply different "personal" ASA" with respect to differing scene contrast ranges.

 

[Stephen Benskin]

First of all, I haven't "blown off" anything. I've described the ISO standard for what it is - a way to consistently define film light sensitivity across manufacturers and film types.

If you look upthread you will discover that I am more than versed in research methods, have spent some time doing them myself. But that's not what I entered into discussion here, nor did I ever claim it was. I am describing how I work and providing examples. I am utterly indifferent to meeting some academic definition of measurement to satisfy internet pedantry. If you don't like the outcomes you see, that's fine with me, but other curious minds wanted to see examples of how I was working.

The first stage of a lost cause it demanding "citations" or "proof". This isn't a research lab, it's a place sharing practice.



Dismissing a whole group of people as "Dunning-Kruger cases" is arrogant and condescending. It smacks of "I'm so smart"-ism and is unnecessarily unkind. I've done plenty of lab work, experimental design, and statistical reductions in my lifetime - well ... enough to realize I didn't like it all that much - and I didn't ever believe it gave me license to be unpleasant to other people.




So what? The ONLY thing that ultimately matters is the final image. Not whether someone has done a quantum chemical analysis of state changes in silver halide production. There are people for whom this sort of fussy detail matters and for whom doing things like defining ISO standards is part of their daily practice, but it's not what they're doing here.

I repeat, using meters that check to be reasonably accurate, and thermometers that are known to be accurate, and shutters whose errors are known, and consistent water and developer formulations, I never got good shadow detail using ISO speed with any film or developer using standard development practice - ever. And I'm not alone by a long shot.

You misrepresented what the ISO standard was when you wrote, "But this is only obliquely related to what any given individual will actually realize in practical use." So I reference the first excellent print test by Jones, which used prints judged for quality as the connection to practical use. It was the field of psychophysics I was referring to.

I wish to clarify the use of the Dunning-Kruger joke in the Zone System story. The Dunning-Kruger effect doesn't mean someone is stupid. According to Wikipedia, it means people "overestimate their abilities." Like the people who were limited in their knowledge to Zone System testing. They were unaware, not stupid. Because their knowledge was limited on the subject, they were more likely to draw bad conclusions without realizing it. Conclusion, people need to be made aware of the facts in order to make informed decisions and without the facts, they may not know the decisions they make are mistaken. If you truly believe I meant otherwise, I apologize for giving you the impression.

Carl Sagan said "extraordinary claims require extraordinary evidence." You made an extraordinary claim about the ISO speed standard, “I have yet to see any film hit full ISO speed in practice when using conventional development.” Hitchen's razor states, "what can be asserted without evidence can also be dismissed without evidence." I pointed out that unsubstantiated claims are opinions. I also pointed out that opinions are fine. (Your images are an example of proof. I personally would like more details in order to form a better conclusion.) As I said your ISO statement comes across as a definitive statement, which implies some kind of proof. As a site for learning, I believe we need to be clear whether we are stating a fact or stating an opinion and more information can only be beneficial. Personally, I couldn’t care less how someone exposes or processes their film. Any disagreements I have are generally not about exposure but usually on a point of fact or theory.

My thoughts on exposure are that there is no need to test for film speed. If anyone has read any of my posts, they will find that I suggest using the ISO speed as a reference and do a little shooting to see what EI works best. Save the testing for determining development. My posts also contain tone reproduction theory and exposure theory, so I’m always willing to discuss film speed.


For anyone interested in unfiltered access to the seminal first excellent print test series, the papers are:

Jones, Loyd, The Evaluation of Negative Film Speeds in Terms of Print Quality, Journal of The Franklin Institute, Vol 227, N. 3, March 1939.

Jones, Loyd, The Evaluation of Negative Film Speeds in Terms of Print Quality (conclusion), Journal of The Franklin Institute, Vol 227, N. 4, April 1939.

Jones, L.A. and Nelson, C.N., A Study of Various Sensitometric Criteria of Negative Film Speeds, JOSA, Vol. 30, N. 3, March 1940.

Jones, L.A. and Condit, H.R, The Brightness Scale of Exterior Scenes and the Computation of Correct Photographic Exposure, JOSA, Vol. 31, N. 11, November 1941.

 

[Stephen Benskin]

Film speeds magically doubled overnight in 1960 when the safety factor was eliminated from the ASA standard. The ISO standard was not adopted until 1993. This has been alluded to several times in this thread.

Actually the 1993 edition is a revised edition. According to the forward, "The second edition cancels and replaces the first edition (ISO 6: 1974)".

 

[Stephen Benskin]

I don't know where this "profound truth of the universe" stuff comes from. Personal film speeds are personal because they take into account personal equipment and personal working methods.

If you think about it, film speed isn't influenced by any exposure device. It's a product of how the light sensitive material reacts to exposure under stated processing conditions. The use of personal film speed in this case is a misnomer. It should be more like personal EI. To actually test your EI with your equipment, you would need to have every lens tested for t/stops. Shutters also vary, so you would need to do the speed test with every lens (bench tested for t/stops), at every shutter speed, and after that it still doesn't take into account personal tastes and metering preferences. Not very practical.

There was a sentence added to the end of my Zone System story, "nobody noticed that their personal Zone System speeds were effectively the same and differed to the same degree from the ISO speeds." Those who do Zone System testing generally find their EIs to be 1/2 to 1 stop slower than the ISO speed. With that high degree of agreement, how much personalizing to one's own equipment can there actually be? I think it's more like creating a false sense of control. Although finding the 0.10 point is important for the Zone System contrast determination part.

 

[Steven Lee]

If you think about it, film speed isn't influenced by any exposure device. It's a product of how the light sensitive material reacts to exposure under stated processing conditions. The use of personal film speed in this case is a misnomer.

Thank you for saying this. This "personal speed" jargon makes zero sense. It's like saying "personal film weight" or "personal temperature of the sun".

 

[MattKing]

This "personal speed" jargon makes zero sense

I know you already realize this, but I'm sure you now appreciate why the "what speed are you getting" language in your opening post was bound to release this runaway train!

 

[DREW WILEY]

It's always nice to hear about good ole snake oil salesmen like Fred Picker and how "scientific" and "consistent" the methodology of these various Zone gurus allegedly was, as if every film was an eight-segment long Triassic X centipede that was somehow ironed out perfectly straight. Or seven segments long according to some, or any number of segments according to others, or basically a rubber band which you can stretch or contract any manner you wish.

Then when none of it really matches, the shutter speeds and meter and flare factor gets blamed, as if any kind of serious calibration doesn't tightly control all of those variables right from the start. But all the ole wizards had their magic hats to peer into, or could catch an owl and examine its entrails.

That's why, once you get serious, you need to look at actual published film curves, and not just what's posted on the box, and it's preferable even make you own densitometer plots based on your own needs and parameters. And in that respect, "personal ASA" is every bit as valid and scientific as any manufacturer version based on some mathematical model that doesn't necessarily equate to either real-world usage or serve as an ideal mode of comparison between separate films. It's just a starting point! (Color film speeds are necessarily calculated somewhat differently,)

And that in turn is why traditional curve plotting sheets were on translucent paper, so that the respective plots could be placed over one another atop a light box for sake of visual comparison. Of course you could do that with different colored pencils, or now on a computer screen, but it's all the same idea.

And yes, there is a personal temperature of the sun, depending on how close you get to it, and even where you happen to live at the moment. And its own "surface" temperature is uneven, and subject to certain conditions. Let's face it; an awful lot concerning photography is subjective. Otherwise, it would be boring.

 

[Mr Bill]

Dismissing a whole group of people as "Dunning-Kruger cases" is arrogant and condescending. It smacks of "I'm so smart"-ism and is unnecessarily unkind.

I was gonna respond to this but Stephen beat me to it. But I'll add some anyway.

I don't believe that it should be seen as insulting in any way; it's just a study, to the best of my understanding, where people rate their own performance on a task, and there was an observation that lesser-skilled people tended to overrate their performance. Now, I've not looked at it for a looong time so I could be wrong, but that is my recollection.

I see it as something that might be expected because a "new" person at a task probably doesn't see all the possible intricacies. So they get through it and think they did pretty good. I've seen a lot of people get something of a wake-up call when they encounter someone who is much better than they at something they thought they were pretty good at.

I suspect that a lot of people DO use the term as a veiled insult but imo that's not a justification to presume that some other given person is also doing so.

 

[Mr Bill]

I've not weighed in on this topic so far as it is primarily about some specific b&w film. Whereas my serious day-job experience has been primarily with a handful or two of pro color neg films. In my work we did extensive testing on the specific film of the day - sensitometric testing with a known-calibrated sensitometer, practical shooting tests in our own studio setups, heat stress tests, consistency tests between emulsions; even image stability (fading) tests.

We found that these films came in within spec on ASA speed tests, and when using known-calibrated Minolta Auto-Meter flash meters in a more or less standard studio setup the resulting film exposure came in right on the money vs aims. (Aims were established by Kodak in the form of density aim values, as well as with printer setup negs that included a "normal exposure" negative.) Our on-the-money negs were a close match to the Kodak exposure reference. When optical prints were color corrected by hand the resulting prints had just beautiful color.

There was just very little ambiguity with this. If someone tried to duplicate this and failed I'm sure there would be a very clear reason why - bad meter cal or usage, poor processing, etc., but it would almost certainly not have been a fault of the film.

But... this thread is about b&w films which, I guess, allow a lot of ambiguity.

 

[faberryman]

If you think about it, film speed isn't influenced by any exposure device. It's a product of how the light sensitive material reacts to exposure under stated processing conditions. The use of personal film speed in this case is a misnomer. It should be more like personal EI. To actually test your EI with your equipment, you would need to have every lens tested for t/stops. Shutters also vary, so you would need to do the speed test with every lens (bench tested for t/stops), at every shutter speed, and after that it still doesn't take into account personal tastes and metering preferences. Not very practical.

I agree that the term personal exposure index is more accurate, but the term personal speed test is in the vernacular and most people who are likely to be doing the tests will know what you are talking about and will use it themselves. I don't think you need to test using t-stops on every lens and at every shutter speed for the test to be useful. Besides, you are unlikely to be able to select shutter speed and f-stop combinations which would allow you to precisely implement the results of such tests when you are actually making photographs. The perfect is the enemy of the good.

 

[Stephen Benskin]

I agree that the term personal exposure index is more accurate, but the term personal speed test is in the vernacular and most people who are likely to be doing the tests will know what you are talking about. I don't think you need to test using t-stops on every lens and at every shutter speed for the test to be useful. Besides, you are unlikely to be able to select shutter speed and f-stop combinations which would allow you to precisely implement the results of such tests when you are actually making photographs. The perfect is the enemy of the good.

That's not my point. It's more questioning its validity. A thought experiment if you will. How effective is the test at what it proposes to do? My opinion is it's more myth than reality and it creates a false sense of precision / accuracy. The biggest influence in exposure is the photographer's personal preference and metering approach which isn't part of that test.

 

[faberryman]

That's not my point. It's more questioning its validity. A thought experiment if you will. How effective is the test at what it proposes to do? My opinion is it's more myth than reality and it creates a false sense of precision / accuracy. The biggest influence in exposure is the photographer's personal preference and metering approach.

Is the ISO test done by the manufacturer not valid either because it does not test each of your lenses at t-stops and your camera at every shutter speed? Does the ISO test give you a false sense of precision? Is the ISO test more myth than reality? Shall we disregard both?

 

[pentaxuser]

I agree that the term personal exposure index is more accurate, but the term personal speed test is in the vernacular and most people who are likely to be doing the tests will know what you are talking about and will use it themselves. I don't think you need to test using t-stops on every lens and at every shutter speed for the test to be useful. Besides, you are unlikely to be able to select shutter speed and f-stop combinations which would allow you to precisely implement the results of such tests when you are actually making photographs. The perfect is the enemy of the good.

That certainly is where we seem to end up on most threads unless our interest has died of exhaustion somewhere along the way. It can be a real problem in my opinion when we are dealing with newcomers( In case this leads to another diversion, I am not referring to Steven here ). We forget the level of knowledge of the person who asked the question and don't make inquiries of that person's knowledge or misunderstand what is being asked of us in the original question or often the subsequent replies the OP makes

We lose focus on the customer(the OP) and ignore the need to know what he wants to know before we can give an answer to what he want to know

Mind you I don't suppose we will ever change

pentaxuser

pentaxuser

 

[chuckroast]

Thank you for saying this. This "personal speed" jargon makes zero sense. It's like saying "personal film weight" or "personal temperature of the sun".

Imagine you have a film rated at some ISO. Imagine further that your light meter is off by one full stop. Even assuming ISO is a practically useful indication of a film's light sensitivity, if you use your meter set at the ISO indicated value, your exposures will be off by one full stop.

The film hasn't changed its sensitivity, but your "personal speed" will be different because of your tooling/workflow etc. So, yes, "personal speed" makes plenty of sense and its generally understood to mean just that.

It's analogous to buying a new car. The EPA mileage estimate is a useful way to compare the fuel efficiency of different brands, but it doesn't magically map to real fuel economy. Actual fuel consumption is influenced by how you drive, your tire inflation, the kinds of routes and distances you drive, temperature, fuel type and so on. You have a "personal fuel efficiency" number which typically isn't the same as the EPA estimate.

Debating "speed" vs. "EI" is sort of pedantic at this point. The notion is pretty widely used and understood.

 

[Steven Lee]

Chuck,

Your example above is a story about exposure. Film speed has nothing to do with it. Even unexposed/unopened box of HP5+ sitting in a fridge has ISO speed rating given to it by a manufacturer

Debating "speed" vs. "EI" is sort of pedantic at this point. The notion is pretty widely used and understood.

Pedantic, yes. Maybe I am overly exposed to young people who're confused as hell by this language. Imagine yourself not knowing _anything_ about these matters and then try to read some comments that use "personal speed" language and try to think how that can be interpreted by a newbie. Let me help you: the beginners interpret this as the ability to change film speed by turning the ISO dial on their film Nikons just like they do on digital Nikons. And when I tell them that you cant' change film speed, they point at something they saw on Photrio.

Drives me nuts.

 

[chuckroast]

That's not my point. It's more questioning its validity. A thought experiment if you will. How effective is the test at what it proposes to do? My opinion is it's more myth than reality and it creates a false sense of precision / accuracy. The biggest influence in exposure is the photographer's personal preference and metering approach which isn't part of that test.

You don't judge the merits of an idea by its bad practicioners or misapplication. An idea rises- and falls on its own merits. Sure, people new to any discipline may overrate the value of the tools they are learning, but that doesn't invalidate the tooling. They're just on a learning curve (like all of us).

The notion of figuring out "personal speed' (as the term is ordinarily used and understood) is entirely reasonable. It's reasonable whether your point of departure is published ISO speed or you're chasing the infamous 0.1DU over FB+F, or any other metric you find helpful.

Moreover, people should be discouraged from the notion that this testing provides either absolute accuracy and certainly not for precision (well, the BTZS people might take issue with that). We do this to achieve repeatability and consistency and nothing more.

[ENTIRELY OT] As an aside, one of the greatest educational mistakes made in my lifetime was moving young people away from the use of slide rules. Calculators have enabled several generations of students to bang out "correct" answers without actually understanding the underlying mathematics. It is astonishing how many people do not understand the difference between accuracy and precision, cannot do first order estimates, or visualize even the simplest arithmetic problems. Slides rules long ago lost their currency for the practicing scientist, engineer, or accountant, but they are really useful in help young minds "think math".

 

[chuckroast]

Chuck,

Your example above is a story about exposure. Film speed has nothing to do with it. Even unexposed/unopened box of HP5+ sitting in a fridge has ISO speed rating given to it by a manufacturer



Pedantic, yes. Maybe I am overly exposed to young people who're confused as hell by this language. Imagine yourself not knowing _anything_ about these matters and then try to read some comments that use "personal speed" language and try to think how that can be interpreted by a newbie. Let me help you: the beginners interpret this as the ability to change film speed by turning the ISO dial on their film Nikons just like they do on digital Nikons. And when I tell them that you cant' change film speed, they point at something they saw on Photrio.

Drives me nuts.

I can honestly say that I have never once found some struggling to understand why box speed may not be the speed they need to use when metering once it is clearly explained to them. Beginners make beginner mistakes. We can help clarify. Then we can go on to make our own experienced mistakes

 

[Steven Lee]

Chuck,

Unless you have a reason to believe that a manufacturer doctored data, ISO film speed is the speed you ALWAYS use when metering. That's the explanation they need. That's the end of story.

Then you should follow with a lesson on how to expose to get the desired result, which should include concepts such as EV, 18% grey, reflective-vs-ambient-vs-spot metering. As an advanced topic, characteristic curves can be introduced (or simplified ZS).

And finally, the 3rd concept is developing. Separating innate film characteristics from exposure and development is key. Basically, Adams got it right when it partitioned everything neatly into those 3 books.

But using the "personal speed" language you're crossing the boundaries of these concepts and that is super confusing. Once a beginner spends a weekend on photrio, I suspect they'll need some kind of a "jargon detox" to clean up their minds before they're able to ingest new information.

There's another similar confusion that hits everyone: the pushing and pulling. 9 out of 10 believe that pushing happens by tweaking the ISO dial on a camera. They show up at the lab here proclaiming "here! I pushed this film two stops! now develop it!".