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There are condenser enlargers with small coated bulbs in black housings, and condenser enlargers with large coated bulbs in white housings. Not to mention point sources. The degree of diffusion is quite different, so I can't imagine a single perfect target CI for all of them and all subjects. I suspect diffusion enlargers are more similar to each other, but even then there are differences, depending on how effective the diffusing system is. You've got to start somewhere, but after that everybody has to make their own adjustments.
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Aim CIs are based on the following formula:

 

Desired Negative Density range / Log Subject Luminance Range - Flare

 

So for a diffusion enlarger Kodak's current figure is 1.05 / 2.2 - .4 = 0.58

 

I've uploaded a CI comparison chart calculating various CIs for slightly different values (mostly flare). In the following post, I will upload Kodak's CI chart.<div>007gUr-17026084.jpg.223798c89c2f1b5828e52c10640e540e.jpg</div>

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Conrad is indeed correct. These are average figures, and are starting points. Lenses that are newer are generally better in contrast, so developing times should be coming down ever so slightly over time, as lenses on both ends of the system improve.

 

But it certainly is true that condensers require less development.

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This upload is Kodak's CI chart for both diffusion and condenser. It is fairly large.

 

BTW, on the last chart the "adjusted flare" columns are based on a changing flare factor. All the other columns uses a fixed flare factor. A changing flare factor should be more accurate because as the luminance range changes so does the flare. In this way flare works a buffer. As the luminance range increases, you don't have to pull as far because flare increases and effectively decreases the illuminance range at the film plane. As the luminance range decreases, flare decreases so you don't have to push as much.

 

What makes this fun is the flare figures are average and can vary depending on the tonal distribution of the scene. This could mean using a fix flare value can be just as legitimate as a variable flare scenario.

 

Kodak's numbers in the previous chart are based on speed pushes. The difference between a speed push and a contrast push is a speed push is 2/3 stop (0.2) difference and a contrast push is 1 stop (0.3) difference. On the Kodak CI chart, they are using contrast differences. Notice how their values for grade two at 8 1/3, 7 1/3, 6 1/3, 5 1/3, and 4 1/3 match exactly the values in my chart for CI values N = 0.58.<div>007gVk-17026384.thumb.jpg.dd37a63149c4cf8ef3558ac9aef018df.jpg</div>

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Hans, I was Donald's queston. BTW, the average luminance range is log 2.2 (7 1/3 stops), and your link http://www.kodak.com/global/plugins/acrobat/en/service/Zmanuals/z-133.pdf

is about control strips and not Contrast Index. Sure they use the term CI, but it really isn't. It's one of those cases where they wanted to simplify and just make things more muddy. I guess you can call the process control CI "relative CI."

 

Conrad is right that different systems produce different results. That is why it is important to test your printing conditions which will give you a personal Desired Negative Density Range to plug into the formula. Of course, it's never as cut-and-dried as it sounds. L.A. Jones in 1948 concluded that a paper's LER isn't a hard and fast rule because of the perceptual aspects of the printed image, but it is the best possible approach. Or as Churchhll once said, "Democracy is the worst possible form of government, except for all the other forms."

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Lex, what happened to the rest of this thread? Is it my imagination or is this site down a lot lately?

 

In an attempt to continue, here's a response to something that doesn't seem to exist anymore.

 

Dean noticed that the "techies" didn't have any images uploaded.

 

To negate a person�s technical expertise simply because they do not personally participate in the application of that knowledge is fallacious and disrespectful to the achievements of many great pioneers in the history of photography. As far as I know, the person who has had the largest influence on the definition, standardization, and practice of photography, L.A. Jones, didn�t do personal photography. Fox Talbot invented the negative-positive process and then moved on to other things. C.E. Kenneth Mees, perhaps the greatest influence in photography as well as a pioneer in industrial research, doesn�t have a book of his photographs. He did, however, establish Kodak�s R&D department and was almost as responsible for Kodak�s success as George Eastman. BTW, Mees also hired Jones. These incredibly intelligent people, as well as many more, are the ones who have made it possible for a grandmother to photograph her grand children without having to worry about how it all works.

 

Dean, in an attempt to fix the picture problem, I've uploaded a recent image of mine. The reason why I don't post images on Photo.net is because for me it is an information website.<div>007gjG-17030884.jpg.bb9aac55675b4b768aea2194c36d2213.jpg</div>

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Stephen, photo.net's RAID array overheated and crashed around March 12th. Brian tried to rescue the database for that day but no go.

 

It appears to have happened again for some of yesterday's posts. I'm sorry for that because there were some interesting and informative contributions on the 14th. And it's frustrating trying to reconstruct our thoughts - usually if one of my comments gets lost I just don't bother again.

 

Anyway, trust me, I didn't delete or edit any of your comments. I'd be more likely to edit *my own* comments considering some of the stupid things I've said. (BTW, I don't do that either even tho' I could - whatever I write stays, no matter how idiotic or wrong. I'll 'fess up later if anyone catches me.)

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Stephen;

 

While I agree my comments were mildly sarcastic, I didn't mean to disparage those of a scientific bent, such as the persons mentioned in your above post. What seemed to me to be a somewhat humorous opinion at the time apparently took on a vitriolic nature in print. For that, and to you, I apologize.

 

Sincerely,

 

Dean Williams

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Dean, thank-you for your apology. The thing is you were the third person to bring up the concept that to be technical, you don't shoot, and therefore your technical knowledge isn't valid. This seems to me to be a potentially interesting topic to explore. Is this a common perception? Is it a defense mechanism? I mean no one actually came forward to argue against any of the facts I presented. Skepticism is always good, but I thought people are supposed to be skeptical in the absence of information, not in its presence. For me, I'm so skeptical, I can hardly believe it :>).

 

But seriously, why is there a common belief that technical equals bad or no photographic ability or to be technical and not personally shoot somehow invalids their opinions on photography?

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"...I'm so skeptical, I can hardly believe it :>)."

 

I'm gonna steal that line, Stephen.

 

"But seriously, why is there a common belief that technical equals bad or no photographic ability or to be technical and not personally shoot somehow invalids their opinions on photography?"

 

I'm not sure that it's a *common* belief. Many of us, including me, studied photography more or less formally. I did in school, right down to the topics of characteristic curves, CI, the Zone System, etc., all of which I've obviously forgotten for the most part.

 

It's just that at some point many of us decide to pretty much wing it, melding our earlier studies (and usually terrible photographs) with our later experiences (and, hopefully, better photos). I think photographers of that nature tend to be mostly 35mm shooters and some MF shooters as well.

 

Large format shooters seem to remain technically inclined longer. That makes sense. The entire pursuit of LF photography requires greater discipline and would naturally involve the more technically minded folks for various reasons.

 

Of course I know there are exceptions but I'm too busy taking photographs to ennumerate them. ;/

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"The thing is you were the third person to bring up the concept that to be technical, you don't shoot, and therefore your technical knowledge isn't valid."

 

Stephen;

 

 

I don't believe that to be technical means you don't shoot. I know that some shooters are also very technical and they may be the ones most likely to achieve the results they desire with the least amount of fuss (mistakes). I am fairly sure that there are many on the other end of the stick, completely uninterested in the tech side of things, who also produce their share of fine photographs. Lots of people probably fall somewhere in the middle. The folks I cracked wise about would be the ones with an apparent abundance of technical knowledge, from various sources, (mainly print) but seem to have nothing to show for it. Now, don't get me wrong here. The value of the information to be found in various photography books is enormous. But, some take it as the be all and end all. "This is the way it shall be done".... I'm not from Missouri, but I want them to show me, rather than spout dictum. This where my own skepticism kicks in. For example, a question might be:

 

Junior asks:

"Can I develop my film in tomato juice?"

 

Bubba answers:

"No. It is not possible. Here is a picture from a book I read that says it won't work."

 

A second answer from Jack-of-all-trades:

"I read that book too, but I tried it anyway, and it does work, but the shadows are dull and highlights block up badly. Here's a picture of my results.

 

Silly example, but you get the idea. Both answers are from techies, but Jack's put the information to the test. He's a techie and a shooter.

 

"Is this a common perception?"

 

It could be. I certainly can't speak for anyone else, of course. The best anyone can do is guess, and that's all I would presume to do in this case. It's possible that people involved in street photography, landscapes, portraiture and the many other venues, don't consider those who take pictures of test targets, and fret over grain size and maximum film speed to even be photographers, lacking other evidence. (I am not making any judgments here!)

 

"Is it a defense mechanism?"

 

Another possibility. Charts and graphs are not everyone's cup o' tea. Some may find them confusing. Then again, some may just be bored.

 

"This seems to me to be a potentially interesting topic to explore."

 

I agree? No, I mean, I agree!

 

Dean Williams

 

p.s. I'm with Lex. That is a great line!

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Let me start off by saying I'm not attacking Dean on this issue in any way or directing any of the following statements towards him. He and some others have only presented the opportunity to discuss a topic that has been present in many threads and for some time.

 

If you think about it, almost everything we know comes from a commonly accepted notion of the truth. I know the Earth circles the sun because someone told me so. Even knowing that, I still wouldn't be able to prove it to someone who didn't believe it. I�m not sure why I brought that up.

 

In Dean's thoughtful example, he says, "A second answer from Jack-of-all-trades: "I read that book too, but I tried it anyway, and it does work, but the shadows are dull and highlights block up badly. Here's a picture of my results. Silly example, but you get the idea. Both answers are from techies, but Jack's put the information to the test. He's a techie and a shooter." To this I ask is it the same thing if Jack said he tested it himself and it works and here's a GRAPH of the results? The tests were still done. He has proven it works, and he also has very precise information on how it works.

 

My examples all come from my testing. They are about going out there and trying it except that instead of using a camera, I use sensitometry (in the case of the Zone System exposure discrepancy, I did confirm it using a camera and standardized ZS testing.) Using sensitometry simple limits the variables, increases accuracy, repeatability, and clarity. One of the things I like about graphs is that they are visual. Being visually oriented, they are a god send. They also clearly tell you what you are comparing. Yes, it takes some getting used to but what doesn't?

 

I agree with Dean that some might find sensitometry to be dry. I do. It's abstract. I used to frequently fall asleep while reading some technical paper filled with lots of math and strange ideas, and when discovered by (woken up by) someone I would either say I was "researching" or "reflecting on the material." It became a joke that to sleep was to do research. It's not that the subject can be boring. It's the reaction to it. I think quantum theory is boring. I could tell quantum physicists to stop wasting time. What does uncertainty principles and subatomic particle tracts have to do with anything? Go play on a computer or watch TV. Oh wait, right, there wouldn't be computers or television without quantum theory. Boring, yes, but not impractical?

 

It�s obvious to me the control and (let�s face it) BS meter sensitometry offers. So it�s hard to understand the reason why this reaction is so pervasive throughout this forum, but I am equally curious to understand why? Lex�s statement that 35mm people may not maintain their technical interest as long as LF shooters is interesting and makes sense, but it doesn�t address the cause of the dismissive nature they have toward the technical.

 

Thoughts?

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Dean (and Lex):

 

One should not presume that anyone's participation in posting here, which is, after all, a technical forum, precludes the production of serious work, or that testing in and of itself does so. Speaking for myself, I hardly ever did exhaustive tests until recently. I did, as do many, perform casual trials, which seemed quite sufficient for my purposes, when, years ago, I was more active in photography. In those days, quality of results was of secondary importance, and in any event I did not process all of my own B&W photographs simply because I did not have the time.

 

Now that I have less time for this hobby, I wish to have the maximal quality I can for the investment I have made in lenses and my own skills and knowledge. I am no longer interested in, and thus no longer produce, pushed-film images of rock bands, though I do have one to show you if you wish.

 

As we get older, our interests change, and in my own case, I have returned to this hobby after having givien it up completely, even renouncing it. The terms under which I make my return are my own, not anyone else's. If I now wish to place greater emphasis on consistent, sound darkroom technique than in the past, that is because I am more willing to engage in discipline than before. I admit that much of my knowledge comes from making mistakes. I once recall having a conversation with someone who was looking over my shoulder at a roll of slides that I was scanning through when I was picking them up. He expressed surprise that every one was perfectly exposed. I told him that this was not difficult. He simply could not believe that it was possible with a manual camera, given the subject matter. I explained to him that this was the result of long hours of practice, and making plenty of mistakes. Just as a musician practices his instrument for hours at a time, I would practice handing and manipulating my cameras without film in them, so that when the occasion arose, I was ready and my reflexes were sufficiently honed.

 

Back to the point:

 

There has been considerable erosion of once-commonplace photographic knowledge. When I refer to a book or manufacturer web site, it is not because I just learned this yesterday, or that I have not tested it myself. It simply is a means of making available to many that knowledge which has been available in the past but has forgotten or ignored.

 

The values of CI that Kodak has recommended for diffusion and condenser are of quite long standing. They are not news. It is unfortunate that many people have in fact never heard of them. That is why I presented them in this thread. Some would argue that the values are wrong or irrelevant. To this I would simply reply that the values are averages, and that as such, slight deviations from them are perfectly permissable. But if someone claims that a CI of 0,75 is the best for 35mm film with a condenser enlarger (and I am sure someone out there will make such a claim), I would have to say that this represents enough of a deviation to be an 'error', not an aesthetic choice.

 

'Aberrant' practices have become much more popular than before, due to the fact that many more students take classes in photography than in past, and this has created an atmosphere of confusion, as one student tells another this or that 'tip'. It is possible to develop one's film any number of ways, and print it any number of ways, and get some kind of results that may please someone. What standards serve to do it provide a reference point, so that the aberrant does not become the norm.

 

It is possible to establish, through trial and error, the validity of these recommended CI values. Since most of us have better things to do with our time, the amount of testing we perform has to be relevant. Since the time when I was much more involved in B&W photography, new emulsions and developers have made their appearance, and others available for a number of years never found their way into my work, simply because I was not motivated to experiment. I was also using Kodachrome almost exclusively for the last 10 years or so, and avoiding B&W.

 

Thus, recently, I have begun a series of tests on these new or unfamiliar B&W products, to bring myself up to date with them. When this testing is completed, I shall begin a more active phase of photography. In any event, I would not be inclined to display that work here.

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Stephen;

 

"Lex�s statement that 35mm people may not maintain their technical interest as long as LF shooters is interesting and makes sense, but it doesn�t address the cause of the dismissive nature they have toward the technical.

 

Thoughts?"

 

 

Just a few.

 

I would think that most people do get into a technical way of thinking, however rudimentary, once they have decided to take their photography seriously. It my not evolve into the true "techie way", but through some kind of trial, or happy accident they end up changing their EI or developing for different times than recommended by manufacturers. Those that don't may end up thinking they should bracket every shot and hope for the best or just get used to accepting what they get. I know this isn't true for all, it's a generalization. Those that do test throughly, although without the use of a numeric system, probably have a pretty fair chance of getting consistently good results, and once they reach a point where things become predictable using their own system they quit testing and stick with what they know �til they decide to try another film. In my opinion, someone that has been using a given film for an extended time, and is having what they consider good success (wether real or imagined) might very well be dismissive of more technical methods. After all, if they can produce consistently fine prints just by finding their own best EI and development for the contrast they need, they probably don't see, or have, the need to start drawing up graphs and charts. The Tech, while proving, or illustrating something in a technical manner may garner the remark "So what?" from one or "Huh?" from another, while all three may be producing equally excellent results.

 

So, there you have it. My personal missive on the dismissive :^)

 

Of course, (and here we go again), these are just my opinions, and are not directed at anyone. There is more to comment on from your post, Stephen, but right now it's bedtime.

 

Dean Williams

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Hans, I appreciate your balanced position in this thread. It's been very interesting.

 

And I respect the arc of your experience you've described that's led you from one place in photography to a more technically oriented position. It's the first time I can recall you describing your thoughts so succinctly and without an agenda. I hope that doesn't sound condescending - I don't mean for it too. But I have to acknowledge the way you've stuck to your guns while improving your marksmanship.

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I totally agree that you don't need to be extremely technical to get excellent results. Dean, I couldn't have said it better. I'm one of those people who have only shot one film type. It's done what I want it to do, so why change? All the films I have tested are connected with the job I did. Otherwise, I wouldn't have the need nor desire to do all that testing.

 

I do; however, tend to like to find out the reason or the why of stuff. How deep that goes depends on how much I care about it. With photography that is a lot. That's my story. I don�t expect others to do the same.

 

The question remains, why would a photographer who only uses one film and gets great results from it, still feel it necessary to disparage another proven approach that only offers to further knowledge? The thing is this is not just about saying to oneself �it�s not for me,� or "who cares?" It�s not even about taking the energy to write �no thanks, not interested.� They are actively expressing a view that discounts an entire field of thought all together. This is puzzling. BTW, also puzzling is the limited amount of people willing to discuss an issue. They do seem to come out of the wood work to suggest a film and developer though.

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"The question remains, why would a photographer who only uses one film and gets great results from it, still feel it necessary to disparage another proven approach that only offers to further knowledge? The thing is this is not just about saying to oneself "it's not for me," or "who cares?" It's not even about taking the energy to write "no thanks, not interested." They are actively expressing a view that discounts an entire field of thought all together."

 

Well Stephen, as with our other posts, this is a guess (or an assumption), but it may be that some people just don't like it. They may not consider it to be necessary, and so it becomes unworthy, (to them). I don't expect that is the case though, but more likely the self defense mechanism you mentioned a while back. They don't understand it, they get the prints they want just fine without it, so lets berate it and maybe it will go away. In this case they should not participate in the thread, or just say "no thanks, not interested" like you said. There are also a couple of things that really seem to set folks off: Including one of the "sacred" (Ansel, Henri, et.al.) in a discussion that points out a flaw (supposed or real) according to any method is bound to start someone howling. The second would be a tech person (I don't have anyone in particular in mind, and certainly not you) dictating the "proper" way of doing things and pointing to their technical expertise to back it up, especially when the Techie is wrong. Remember the "It shall be done" person? It happens now and then. That kind of thing may put non and semi techies on their ear. (Man my ear hurts. Almost as bad as the foot I recently removed from my mouth. Sometimes ya jus' gotta laugh!)

 

"This is puzzling. BTW, also puzzling is the limited amount of people willing to discuss an issue. They do seem to come out of the wood work to suggest a film and developer though."

 

I don't know weather you mean the subject we're on now or the discussion of true technical aspects of film and paper, but either way, it looks like you and I are it, with a bit from Hans and Lex. If you mean the current subject, the thread may be getting down a bit from the top by now. You could start a new one for some fresh views, since all you've heard are mine. :^) As far as the coming out of the wood work thing, well, everyone likes to express their opinion. It's hard to be wrong just by saying what you like. IOW, it's safe!

 

Dean

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