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# Thread: CI of Blank Film

1. Originally Posted by sanking
Ole,

Definitions.

.....

A sheet of unexposed film that has been developed for n period of time will graph on a horizontal line, i.e. at right angle to the vertical or parallel with the horizon.

This discussion shows a great ignorance of language on the part of some people who in other respects appear to be perfectly intelligent.

Sandy King
Sandy,

A sheet of unexposed film has received only one exposure - zero. It will not plot on a horizontal line. In fact it will not plot on a line at all, but in a point.

My native language may not be yours, but I'm fluent in several sciences.

2. Originally Posted by sanking
Definitions.

Fact. A sheet of unexposed film that has been developed for n period of time will graph on a horizontal line, i.e. at right angle to the vertical or parallel with the horizon.

Sandy King
Sandy, sorry - you got that fact wrong. Since you are looking up definitions, please check the mathematical definition of "line". I think you will find, in cartesian space (2 dimensional space, as we use for graphing our film plots) one data value can at most be described as a point on a graph. It is not a line. It requires 2 points, to create a line. You have no "rise over run" with one point and you cannot calculate a slope with only one point.

Your single sheet with only one exposure on it developed for n period of time will graph as a single point. Not a line, horizontal or otherwise.

Kirk

3. Originally Posted by Kirk Keyes
Sandy, sorry - you got that fact wrong. Since you are looking up definitions, please check the mathematical definition of "line". I think you will find, in cartesian space (2 dimensional space, as we use for graphing our film plots) one data value can at most be described as a point on a graph. It is not a line. It requires 2 points, to create a line. You have no "rise over run" with one point and you cannot calculate a slope with only one point.

Your single sheet with only one exposure on it developed for n period of time will graph as a single point. Not a line, horizontal or otherwise.

Kirk
Huh?

4. Originally Posted by Ornello Pederzoli II
Huh?
Sorry Ornello - what did you not understand there? Maybe you should see Ole's answer, he was a little less wordy, but the same answer.

5. Let's do another "thought experiment". I have several sheets of film that have received some uniform exposure. I develop these to some CI. I hand one of these sheets to any one of you so that you can record the density value of that sheet. Based on that information alone, you cannot tell me the CI to which that film has been developed. If I give you another sheet having received a different exposure and a different development (and consequently a different CI), you cannot tell me what the CI is for that film. You can only tell me the density. That density BTW may end up being identical to the first.

I can take any of those sheets with different densities, including a blank film into the darkroom and produce any tone up to and including the dMax of the paper I choose to print upon. In fact, I don't even need to use a negative to get that result.

None of the information you can relate to me about these films has any utility in isolation.

My point is that all of the information derived from a single measurement is useless in practice. And that is what the original poster was interested in-how to understand and use the CI measurement practically.

So, OK. I'll concede the point about a blank film theoretically having a possible CI other than 0. Point taken. Point useless.

Perhaps what we really need here instead of a CI measurement is a BS scale.

Bottom line: I'll not be letting anyone else develop my film, thank you very much.

6. Originally Posted by Ole
Sandy,

A sheet of unexposed film has received only one exposure - zero. It will not plot on a horizontal line. In fact it will not plot on a line at all, but in a point.

My native language may not be yours, but I'm fluent in several sciences.
Thanks. You just proved my point. No slope, no gradient. Nothing but a point.

So what is your point? Are you claiming that a point is a CI?

Sandy

7. Originally Posted by Donald Miller
How many angels can dance on the head of a pin?...
Donald, good question. But you will have to prove to me that angels even exist before I can try to answer this one.

Originally Posted by sanking
I left out the content of your message because it belongs in a category I label as "masturbation intellectuel, inutile et sans plaisir" as we might say in French. You fellows who continue to annoy the rest of us with this nonesense would most likely be a much happier lot if you lost the mental and just used your hands.

With all due respect, Sandy
Sandy, sorry you feel that way. I'm not sure what you have against masterbation, intellectual or otherwise, but are you saying that my analysis of the issue is incorrect? If so, I look forward to hearing why.

And for non-sense, you surely must be addressing the people that suggest that a blank sheet of film cannot be developed to a particular CI. I sure hope so.

I think that Jeff got it - "When we think of the useful data provided by the CI number, it becomes counterintuitive that a blank piece of film can be ascribed a CI or make use of the number, the last point being the crucial one. In isolation, we cannot determine, or make use of the CI of a blank piece of film, even though in theory it must have one, if it has been developed."

Sandy, Mike, Donald, if you would care to correct my analysis, please feel free to do so. As I've said many times on this forum, I enjoy learning new things, and if I'm going around with incorrect ideas on these sorts of subject, I hope someone will help me be better informed. Otherwise, please continue with the masturbation jokes.

Kirk

8. Originally Posted by sanking
Thanks. You just proved my point. No slope, no gradient. Nothing but a point.

So what is your point? Are you claiming that a point is a CI?

Sandy

No Sandy, I disproved your point. Read the whole thread over again, particularly those entries you didn't write yourself.

Or go and find a textbook in basic calculus.

Or just look here: http://en.wikipedia.org/wiki/Calculus

9. Originally Posted by Ole
Or go and find a textbook in basic calculus.
Ole - calculus is not even needed here. No rates of change with only one point. What is needed is plain old simple geometry. Or actually just algebra.

10. Originally Posted by Stephen Benskin

Just a thought Sandy, before you insult more people. I've proven you wrong on a number of points so far. Maybe you're wrong on this one too and just too arrogant to admit it. I think the problem is the self proclaimed keepers of the true knowledge of photography, who aren't ignorant of language as we are, are confusing processing to a CI and testing for a CI.

I've noticed they have formed a little click of ass kissers on this forum and attack those who dane to question anyone in their little mutual admiration society.
Stephen,

No, you have not proven me wrong on anything, though I at least have been gracious enough to recognize that I might be wrong on some things. You, on the other hand, appear to be so high on your own arrogance that I suspect you have to get up on a ladder to scratch your ass when it itches.

A little click of ass kissers who have joined in a mutual admiration society? Jorge and I, for example?

So Stephen, just a thought. Any chance that you might be wrong on this blank film thing? And let's always return to that, shall we, as the thread that brought us together?

Sandy King

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