Donald Miller said:Jorge,
I had the opportunity to view both an example of your work and also an example of another photographer (who shall remain unnamed) pertinant to this thread in the traveling portfolio. I must say there is no comparison. Your print was outstanding. I wish that I could say the same about the other print. However, in good conscience I cannot do that. I was absolutely dismayed at what I saw in the other print, to be completely honest.
A "quick study" apparently does not equate to good prints. There is a vast disparity between "talking the walk" and "walking the talk". In other words anyone can spout jargon...not many can turn out good work.
As I have found in my life's experience...there has been nothing that has caused me more trouble as when I thought that I knew something when in fact, as I later found out, I didn't have a damned clue.
noseoil said:I propose a test. Someone please take a picture, develop and print it. List the SBR, zone numbers or foot candles measured to evaluate the exposure. Project a range of values, then process to a given target value. List the film, developer and whatever numbers will show that theory and practice can be effective. Finally, print the film showing the results in a finished print. (Mike Pry's "early" BTZS pond picture comes to mind at this point, well done Mike) This would illustrate the question in terms more readily understandable than the jargon being bandied about.
Stephen Benskin said:Forget it Jay...It's Chinatown.
sanking said:Your resume of my suggested technique is correct as to the method for determining exposure, but not for determining SBR.
Here is what I suggested. The scene is this. You use your incident meter and take readings, but regardless of where you point it you get the same EV reading, which suggests an overall SBR of 5. To compensate, do this. Record the SBR as 5 and then take another reading, covering the cone of the incident meter with your hand so that it does not see the sky. Record the EV reading and subtract it from the value that give you the SBR of 5 suggested earlier. This will give you the adjusted SBR that will be used to determine time of development.Sandy
sanking said:This is a false analogy in my opinion. SBR refers to subject lighting conditions and is not in any way dependent on either exposure or development.Sandy
sanking said:CI is a slope created by minimum and maximum densities that is measured after development and results from both exposure and development.
sanking said:It might be ok to say that one can develop to an anticipated CI, but to say that one can "develop film to a given CI" when the final result is not the CI to which one is developing is not reasonable.
sanking said:CI has no reality beyond its realization. If you develop to a CI and get some other slope than what was intended then what you have is another CI.
mikepry said:Phil goess into this in his BTZS Lite. Metering for 2 dimmensional objects. I think that may help you here.
Jorge said:You are plotting a curve to find out average gamma, which you can then associate to a SBR value that you will obtain when taking a photograph.
Jorge said:Well the results of my knowledge are posted......anybody else wants to back up their claims with a final print?
Donald Miller said:A "quick study" apparently does not equate to good prints. There is a vast disparity between "talking the walk" and "walking the talk". In other words anyone can spout jargon...not many can turn out good work.
Didnt I write you could plot gradient vs sbr? did I in any way say they were not correlated in any way?Kirk Keyes said:Doesn't Davis use "average gradient" or G-bar, not "average gamma"?
And if Davis is graphing development time vs. average gradient, as well as dev. time vs. SBR, and dev time vs. N, then SBR is directly related to average gradient or N-development values. They are correlated through development time.
Kirk Keyes said:I said: "You CAN develop film to a given SBR, just as you can develop film to a given CI."
OK - but then Davis equates SBRs with G-bar (simplified CI) in his book and software. Look at the graphs he produces with it. Each film plot can display the G-bar value along with the associated SBR.
So is Davis wrong in placing these labels on his graphs? I think not - as he knows that in his system, a particular G-bar IS directly related to the SBR of the original scene.
I'll get back to you on this.
This is splitting hairs. It all really depends on your quality control as I described above. And does it really matter if you are off by a couple of 0.01 CI from your intended target CI?? And if you got achieved a CI that is slightly different than your target CI, then how can you say your blank film got a CI of zero, which you have.
What?? "No reality beyond its realization?" CI is a measurement of a property of film development. Please - let's not start discussing "reality" and "realization".
Kirk, I believe that exact phrase ,"developing to a given CI" was used in the authoritative paper published in the peer reviewed journal Journal of Photographic Science Engineering.sanking said:Kirk,
However, please note that what Davis says in his book is absolutely irrelevant to the definition of CI, and equally irrelevant to whether or not a blank piece of film can have a CI, and also irrelevant to the concept of "developing to a given CI." CI was an established concept in literature of sensitometry well before Davis published the first edition of Beyond the Zone System. So for your discussion of the meaning of CI what Davis may or may not have written about the relationship between SBR and G-Bar is irrevelant, as is my opinion as to whether what he wrote is right or wrong.
Sandy
Kirk Keyes said:Donald, artistic ability and technical knowledge are two separate things. Please don't confuse one for the other.
Donald Miller said:Kirk, I certainly didn't confuse the two...but possibly you could elaborate on why one would not use technical ability, if it was in fact present, to produce work that evidenced technical proficiency. I would like to hear your reasoning on this.
Beyond that my discussion with you on this matter is finished. I guess that you and I will have to agree to disagree. I imagine that should not be a new experience for you.
LOL.....this from a guy sending insulting e mails.....Stephen Benskin said:I don't think it's Kirk's responsibility to explain the concept of civility. Instead, maybe Don should look into some anger management classes and lots of sensitivity training.
Stephen Benskin said:I don't think it's Kirk's responsibility to explain the concept of civility. Instead, maybe Don should look into some anger management classes and lots of sensitivity training.
Stephen Benskin said:Kirk, I believe that exact phrase ,"developing to a given CI" was used in the authoritative paper published in the peer reviewed journal Journal of Photographic Science Engineering.
sanking said:I am perplexed as to why you believe this comment contributes to the discussion? The issue of whether the phrase "developing to a given CI" exists in the literature has not been in question, either in the previous thread or this one. So far as I can recall no one has claimed that the phrase does not exist in the literature. I certainly have not, and in fact I alluded to it in at least one previous message in this thread, for example where I wrote: Even in cases where the term is used to in such a way that might suggest that it is a control or index number for processing, subsequent explanation always makes it clear that that CI is something to be obtained, not the process itself.
Sandy
Sanking said:Kirk,
My connect is with the literature. I have looked carefully at the definition of CI in quite a number of technical books, including several devoted entirely to sensitometry, in order to better understand the issue, and I can find no example where the term CI, when defined, is not associated with a slope or gradient, which clearly shows that it is a result, not a process.
Even in cases where the term is used to in such a way that might suggest that it is a control or index number for processing, subsequent explanation always makes it clear that that CI is something to be obtained, not the process itself. I could agree that the phrase "to develop film to a given CI" describes a process, but the phrase does not redefine the meaning of CI. It describes only the reality of the phrase itself as something that takes place. And even within the context of the phrase in question the literature reaffirms the definition of CI itself as a result, i.e. a slope or gradient that defines two different points of density. Blank film, unless it is unevenly fogged, can not have two different points of density; it can not have a slope or gradient.
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