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Carl Looper

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About Carl Looper

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    Digital Image Technician
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  1. In the older Ektachrome they diverged at dmax, but that may not necessarily be the case for the newer Ektachrome. The curves may very well be correctly drawn. If they are not correctly drawn that would be a very different issue from the typo identified (log10 units vs camera stops) as it would require someone deliberately drawing those incorrect curves.
  2. Correction. In my last post I said: Since unwanted transmissions through impure dyes decrease with an increase in dye density, you could increase the density of the impure dyes with respect to what you might otherwise do were the dyes pure - or what amounts to doing the same thing: decrease the density of the purer dyes with respect to the impurest one. It should read: Since unwanted transmissions through impure dyes increase with an increase in dye density, you want to decrease the density of the impure dyes with respect to what you might otherwise do were the dyes pure - or what amounts to doing the same thing: increase the density of the purer dyes with respect to the impurest one.
  3. I believe the difference in the RGB sensitivity is to compensate for dye impurity. Reversal film can't use the orange mask method used by colour neg, but it can compensate for dye impurities through control of RGB sensitivity. Since unwanted transmissions through impure dyes decrease with an increase in dye density, you could increase the density of the impure dyes with respect to what you might otherwise do were the dyes pure - or what amounts to doing the same thing: decrease the density of the purer dyes with respect to the impurest one. Cyan is the worst offender, and yellow the least, with magenta in between. The density compensation (of yellow and magenta to match cyan) is controlled by decreasing the blue sensitivity and to a lesser extent the green sensitivity of the film, leaving red exposure (cyan density) as a reference. The result is not as good as the neg/print method, but it would be the best achievable given the reversal method.
  4. The curve provides a map between the amount of light exposing the film (horizontal axis) and the corresponding density of the processed film (vertical axis). We can say from the graph that the new Ektachrome has a dynamic range of about 9 stops. The density range of the processed film is 10.7 stops (3.22 in log10 units). The density range is larger than the exposure range to accommodate for darkness adaption in a cinema environment.
  5. The published characteristic curve for Ektachrome 7294 must have a typo. According to the published curve, the film has an input range of only 2-3 camera stops! That can't be right. Previous releases of Ektachrome have had an input range of about 8 stops. However, if we otherwise assume the input scale on the current publication is in log10 units (the "camera stops" title being a typo), the input range would then be 8 stops, (ie. consistent with previous Ektachrome). Previous curves for Ektachrome have had a larger difference in densities at the shoulder. Can we trust the current published curves?
  6. Yes, that's the implication being drawn. Not that I'm entirely satisfied with the analogy as photography, be it digital or analog, will differ from painting far more than they will differ from each other.
  7. With the invention of photography in the 1800s, the market for particular types of paintings (such as landscape and portraiture) moved across into photography. For a little while there was a sense in which "painting was dead" but it was only a particular type of painting that had died: that type of painting which had been dreaming of photography, anticipating it, mimicking it, faking it, in advance of it's invention. A different type of painting would wake up from it's centuries old dream of photography, to pursue alternative visions of what could be done in paint - and that which photography couldn't do (or could only do badly). And photography, for it's part, would pursue what it could do - not just fake paintings. C
  8. In the previous post I suggested that connecting the terminals 1 and 8, opens the shutter, and disconnecting them closes the shutter, however it might be the case (it's been a while since I've done this) that you need to make a connection followed by a disconnection to open the shutter, and then make another connection followed by a disconnection, to close the shutter. Testing with some ad-hoc probes will establish what is required. C
  9. Depending on what you're after you might find it interesting to make your own control unit for the Leicina, allowing (for example) laptop control of the camera. This can be done using an Arduino as an intermediary between camera and laptop. Or one might use a Raspberry Pi. In any case, for control of exposure time, terminals 1 and 8, in the following diagram, do the trick. You connect these terminals to open the shutter, and then disconnect them to close the shutter. You can test this out using ad hoc probes plugged into terminals 1 and 8 on the camera port. Having satisfied yourself this works, you can then wire these terminals to a relay (be it mechanical or solid state), and switch the relay with a micro-controller (such as the Arduino). The Arduino is very easy to program and can provide an accurately timed delay between connection and disconnection of the terminals.
  10. A flashback need not be from the point of view of anyone. It's not as if the past can only exist as someone's personal recollection of it. If we are free (as we are) to move the camera around in space, and adopt points of view that do not belong to anyone in the story, we're also free to move around in time in the same way. To see more than what the characters can see. Or see less. In both space and time. The film itself becomes it's own character with it's own reasons for being at a particular place and time. I recall a great film (but can't recall the name or the director) in which two lovers agree to meet at some cafe on a given date. When the day arrives, we're there at the cafe, the photography establishing the scene. We watch people walking by. Nothing in particular is happening. Some birds on a telegraph pole. People arriving home from work returning to their apartments. But the lovers never arrive. The film ends on this note. C
  11. Am looking forward to seeing the new print. It's playing at our local cinema in 70mm. Have seen this film so many times over the decades. It was one of the first films I ever saw, which might account for my obsession. But then Chitty Chitty Bang Bang was also one of the first films I ever saw and have had no compunction whatsoever to revisit that film at all. C
  12. Yes, I'd agree that by "film look" Yedlin is referencing normally processed 35mm colour neg. But on the digital side he's arguing against any notion of normal processing, ie. arguing that there is no such thing as a "normal" process, or if there were argued such a thing, he would argue against such a conception, and on that basis he would use a particular process (ie. his particular algorithms and workflow) to obtain the particular look he is pursuing - namely the look of "normally" processed film. This can be read in the following exchange between Carvahal and Yedlin, regarding the test ( http://www.yedlin.net/160105_edit.html ): Carvahal: I'm equally weary of arguments that sound superstitious and find that people in the community frequently obsess more about tools than meaning. That being said I sometimes wonder if our brain is able to discern, even on an unconscious level, the difference between the formats. My point being that the difference is not one of resolution, color or technical artifacts, but one of real vs simulated. Yedlin: This last statement is loaded with quite a few implied premises. First off, it presumes that all of film is one monolithic “format” and all of digital is another single monolithic thing. But this is contrary to the truth, which is that each of these (film and digital) is a mere substrate for an image and is also one small step in a long chain of processes that make the thing you’re calling “format" (I mean, you’re not even differentiating between scanned film and traditionally-printed film, which would be two entirely different things if the premise itself — that capturing an image digitally is fundamentally different — is true). Here we see Yedlin argues (quite correctly in my opinion) that film and digital are not monolithic formats - that the terms "film" and "digital" refer to only "one small step in a long chain of processes" that make up a "format". But yet, in his comparison test between film and digital, film will be processed "normally" (we might even say it's processed according to a "monolithic" conception of film) whereas digital will be processed in any way that satisfies what he's after (such as emulating normally processed film). To put it another way, the various potential looks that might be achieved in film (by different process chains) will be ignored, whereas the various options available in a digital process chain will not. Indeed Yedlin will champion a particularly idiosyncratic digital process. The difference between film and digital exists, and despite what Yedlin might hope to argue, such differences can be both exploited as much as they can be suppressed. And of those who exploit the difference, or otherwise appreciate the difference, they are not necessarily "religious" or "superstitious". Creating a work (or a test) in which the differences are minimised doesn't make us (who might otherwise appreciate the difference) any more aware of why we might appreciate the difference. It just makes us feel as if we should consider ourselves stupid. C ​
  13. The only real problem with Yedlin's test is the assumption that the question being asked, in a film/digital debate, is a question regarding which medium to use. In the case of filmmakers who already use film, (or already use digital), or already use both, the question can be entirely different. For example, if using digital, one might ask "what kind of result can I get that I can't get using film", or reciprocally, if using film: "what kind of result can I get using film that I can't get using digital". In other words one might very well be looking for a way to differentiate between the two mediums, rather than minimise such differences. Yeldin's work is certainly fascinating in that he is using digital processing to get what he calls a "film look". But what does he mean by a "film look"? For elsewhere Yedlin argues that it's not the materials that give you a certain look (as such he calls just raw data) but will be in the way you then prepare such. He will argue that is in the processing of such data ("preparation") that a certain look obtains. Does he mean by this that digital processes provide for such preparation, where film does not? Certainly film is more limited in terms of the processing work that might be done, but it's not as if it is completely absent of such - as if it automagically produces a "film look" (or any other look). In film, one can work towards a particular achievable look, as much as one might pursue some alternative look achievable in digital. And the material/workflow differences between film and digital will not be irrelevant. Demonstrating that one can prepare both film and digital in such a way that they both have the same look (what Yedlin calls a "film look") merely demonstrates that there is a small overlapping domain between the two mediums/processes where such an in-common look can be obtained. C
  14. So here's a graphic visualisation of the logic I'm using. For any shutter orientation (left column) can be found (at some other time) a shutter orientation (right column) which exactly counter balances the exposure given by the orientation in the left column. But if both edges of the shutter occupy the frame at the same time (third row), there is no such counter balance to be found (at any other time). This motivates an alternative to a radial design.
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