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#1
11-30-2011, 02:13 PM
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Requesting information about Kinescope process
I am currently researching a book on early (1936-50) American television, and I have in my collection a number of primers or handbooks about television production written at the time by people who worked in the field. In the main they are quite clear, but there are occasionally some things that don't make sense to me. Here is one of them. In his book Movies For Television John Battison notes the compatibility problems between film and video in making Kinescope recordings: different frame rates, and that film consists of a series of still photographs separated by time intervals, whereas video is closer to being one long continuously-created image. Therefore, it is not possible to capture one frame of video with one frame of film without losing part of the following frame of video.
So far, that's clear enough, but then he goes on to say that even if it could be done, it would be undesirable, because the anti-flicker effect of interlacing would be lost. For the life of me I don't see why this should be so. Does anyone have a suggestion? I have attached the relevant page from his book. 
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#2
11-30-2011, 11:55 PM
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Okay if I'm interpreting your enquiry correctly...
Kine recording is done [in North America in your case] at either 24 or 30 frames per second. Your TV system is 30 frames per second, but when we take the anti-flicker interlace process into consideration, its really 60 half-resolution frames per second. [Otherwise known as fields.] So to preserve the "anti flicker effect of interlace" the kine camera would need to run at 60fps, recording each field. [And the subsequent telecine of the kine also at 60fps.] Hope I've answered your question - clearly  On a related matter - conventional 24fps cinema projection also uses an anti-flicker process: two-bladed shutters. So each frame is flashed on the screen twice - 48 flashes per second.
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#3
12-02-2011, 02:32 PM
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He is not explaining what the heck he's talking about in that one sentence, which must have had some particular application in mind (projection of the film? re-televising the film?).
Let me give you an example of a useful process description: The EVR (electronic video recording) TV player developed by CBS labs used 8mm microfilm with two images side by side (either two black and white programs or one color program consisting of a monochrome image and a color subcarrier image). The negatives were recorded in an electron-beam recorder with 60 frames per second. The frames were made from NTSC video that was de-interlaced to make 60 complete frames per second. The line structure was carefully dithered to obscure it so that the flying spot scanner in the player did not have to trace particular scan lines on the film. Now I have described completely a process to use film at 60 frames per second to record 60 field per second video. The single sentence in this book does not give a hint of what process he is describing let alone why it would have a flicker problem. My suggestion is to ignore his sentence because it contains no decipherable information.
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#4
12-02-2011, 07:10 PM
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First of all, let me thank you for taking the time to reply. I'm afraid that I'm still in the dark, so I'll elaborate my difficulty. This is going to be a rather long-winded affair, because I'll have to explain my understanding of the process first.
Battison says that for practical reasons, Kinescope films are made to run at 24fps, chiefly because recording at 30fps would entail buying a special projector just for that purpose, which would be an expense few stations would care to incur. Also, there is no way to reduce the pulldown time enough to capture each frame of video entirely on each frame of film; film stock simply is not strong enough to withstand that kind of sudden movement. So, to record at 24 frames per second involves losing a certain amount of the picture. The shutter will remain open for 1/30th second, and the pulldown will occur in the time remaining: 1/24-1/30 seconds, or 1/120 seconds. This means that when the shutter opens again, half of the first field of the second frame of video has already been scanned. The shutter then remains open until the first half of the first field of the [deep breath here] third frame is scanned, and opens at the beginning of the first half of the second field of the third frame of video. And so, looked at in terms of half-fields of video, the transfer will look like this: 1, 2, 3, 4, [5], 6, 7, 8, 9, [10], etc, where the numbers in brackets represent the half-fields missed during the film pulldown. Now that is clear enough, but then Battison goes on to say that even if these problems were overcome by somehow making film stock sufficiently strong that it wouldn't tear, and the cost could be reduced to the point that that it wouldn't be an added expense, it would nevertheless be undesirable to do so, since the anti-flickering effect of interlacing would be lost. This is where he loses me, although he has the grace to say that it isn't obvious ("another fact which may escape cursory examination is the necessity to retain interlace.") It is just not clear to me how the process I have outlined above, which involves losing some part of the image, retains interlace when, if such a thing were possible, capturing every frame in its entirety would lose it. One other thing I should point out is that I may have done Battison a disservice by only reproducing one page of the chapter on making Kinescope recordings. His explanation up to that point is quite clear.
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#5
12-02-2011, 11:58 PM
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"And so, looked at in terms of half-fields of video, the transfer will look like this: 1, 2, 3, 4, [5], 6, 7, 8, 9, [10], etc, where the numbers in brackets represent the half-fields missed during the film pulldown. "
This is correct. the first 24-per-second frame of film is identical to the first 30-per-second frame of video (half frames 1,2,3,4), but the second 24-per-second frame of film has its bottom half first field coming from half frame 6. then the top and bottom from half frames 7 and 8 respectively, and then the top from half frame 9, which is beginning a third video frame. So, there is a motion discontinuity half way down the film frame on every other film frame. The CRT has to be blanked exactly halfway down the frame and the film position has to be very constant during the four half frames of exposure. On some kinescope recordings you can see that this did not happen exactly, as there is a horizontal line flickering between lighter and darker halfway down the screen. Now,as to flicker: if the film camera used 30 frames per second and fast pulldown, you would get a perfectly fine 30 frame per second film without any of the half-frame mismatch. However, two fields that should be separated in time would be combined in one frame. When this is scanned by an interlaced camera, you get a motion *judder* that is similar to double-shuttering a thirty frame per second film. Maybe that is what the author really meant. I do not see how flicker is any different from the regular 60 field per second video, because the TV picture tube is being scanned interlaced as usual. So, maybe the author confused judder and flicker. Does he use the term "judder" anywhere? There is "3:2 pulldown" judder when televising 24 frame per second film on a 60 field per second TV system. The 24 frame-per-second kinescope recordings, when re-televised as 60 field per second video, have even more complex judder due to the half-field offset of every other film frame. Bottom line, I think the sentence in question is not correct, and the most gracious interpretation is that the author was thinking of judder but was sloppy in his terminology. If I were his editor, I would have said "What did you mean? This doesn't make sense to me." "It is just not clear to me how the process I have outlined above, which involves losing some part of the image, retains interlace..." It retains interlace because in the second film frame the last top half field (9) is the opposite parity of the first top half field (7). Film frame 1: 1 top odd 2 bottom odd 3 top even 4 bottom even [skip 5 top odd] Film frame 2: 6 bottom odd 7 top even 8 bottom even 9 top odd [skip 10 bottom odd] and so on
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#6
12-03-2011, 02:23 AM
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OK, I see what you mean, but at the risk of trying your patience, let's consider the following thought experiment: suppose that we had a film camera that ran at 30fps, and that the pulldown time could be reduced to the time of the vertical blanking interval, so every frame of film captured a video frame without any loss of picture information.
At the time, film projection equipment for television did not use a CRT flying-spot scanner. Instead, they used a modified projector with either a very bright pulse lamp, or an incandescent lamp with a very fast shutter, both of which would produce illumination on the order of 1/1000 second, at 1/60 second intervals, using the vertical synch pulse to initiate the flash. The flashed image would then be directly focused on the photoelectric element of an iconoscope which had its own optical lenses removed. The mosaic plate would then be charged up, and would retain its charge until it was scanned by the electron beam. At the bottom of the scan, the synch pulse would cause the next flash, which would charge up the mosaic again, which would be discharged during the next scan. In the meanwhile, the film would advance to the next frame, and the process would be repeated. And so, one frame of film would translate to two fields of interlaced video, because the interlacing would be accomplished by the iconoscope. Given all this, how would it be possible to lose interlacing? As I said, I hope not to have irritated you too much, but I really want to nail these things down before writing the book. Sloppy research and sloppy writing are an insult to the millions and billions of people who will plunk down their hard-earned cash for it. Once again, thanks for taking the time.
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#7
12-03-2011, 04:37 PM
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Quote:
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#8
12-04-2011, 10:36 PM
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Ok, thanks for sending me this. I think that this particular question poses more problems than normal inasmuch as there is hardly anyone around these days who has first-hand experience with the technology.
You mentioned shutter bar/banding problems in one of your earlier posts. How common were these faults? I haven't looked at hundreds and hundreds of Kinescopes, but I have seen a fair number, and I haven't noticed any so far. And would they be present for the whole film, or just intermittantly?
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#9
12-10-2011, 08:12 PM
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Quote:
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#10
12-15-2011, 11:51 PM
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I never worked on kine recorders but toured NBC Burbank where they were still standing where abandoned. The biggest chore (according to those who worked there) was driving the exposed film to a processor and back in the 3 hours between NY time and LA time. I found it surprising NBC didn't have onsite processing; even our 40-market affiliate had not one but two processors and color at that. They were eventually retired by U-matic of course.
We had a library at the station and the Fink book was required reading. But that was 1977. Could you be overthinking the mechanics and discounting long-retention phosphors? RE interlace, TV projection equipment never had sufficient registration accuracy to achieve interlace even if it were physically practical to operate at field rate/60fps. Kine recording was never wholly satisfactory. That's why the networks leapt upon the VR-1000 when it became available and Ampex couldn't build them fast enough. You've watched kines, what does it look to you is going on RE the artifacts?
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#11
12-17-2011, 02:47 AM
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Well, as I said, I haven't so far watched large numbers of them, but of the ones I have seen, the biggest defect I have noticed is blurry images. However, I am looking at them downloaded from YouTube, so it is difficult to say whether that was present in the original kinescope or exists because of the data compression involved it putting them up. I'm guessing that it's probably a little of both.
I am afraid that I don't follow your meaning when you said "Could you be overthinking the mechanics and discounting long-retention phosphors?" Perhaps you could elaborate on it to make it a little more clear to me. I started this post because I came across a statement in a book which seemed not to make sense to me: Battison said essentially that running the film at 24 fps when making the kinescope would preserve interlacing, but that running the film at 30 fps, capturing each video frame in its entirety, even if it were possible to do, would not retain interlacing. Since I am not a technologist, and Battison was a broadcast engineer of unquestionable credentials, I assumed that I had misunderstood his meaning. However, the people who post on this forum are no slouches, either, and since the consensus seems to be that Battison was mistaken, possibly due to poor editing of the book, I reluctantly have to accept that judgement. There are a few video clips on You Tube and Dailymotion that have kinescope recordings and videotape recordings of the same shows running side by side for comparison, and when you see them together it's quite remarkable how poorly kinescoping compares with videotape.
__________________
One Ruthie At A Time
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#12
12-29-2011, 09:05 PM
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Quote:
There are some issues and questions with the pages originally shown. I asked Rhinehart for the entire chapter, and, I've used OCR on his PDF to recovered the text of the entire chapter. The author of the below article from 1950, either had a very bad day, or much more probably, he was bitten by a copy editor who had to shorten the chapter and had no inkling of what the author was describing. With that said, my experience with Kinescope Recording dates from the early 1960's through the 1980's, and are from the film laboratory end. I hope I'm not missing something here. [My comments are in brackets]. CHAPTER 5 KINESCOPE RECORDING The term "kinescope recording" is one which lends itself very conveniently for use as the descriptive word for a film made of the picture appearing on the screen of a picture tube, or kinescope, in a monitor or receiver. Other words have been, and are, used to describe such films, among them being "video recording". But although the latter is certainly very concise, the author prefers kinescope recording. Use of the word kinescope in this connection makes it available as a verb, as in "kinescoped." Thus television is responsible, as was radio, for the creation of a new word. Whichever one is used does not matter as long as the intention is the same. Phonograph records appeared long before radio was heard: similarly, films were in use long before television; in fact, it can really be said long before radio telephony. Thus, in the early days of radio, programs of "preserved" music were available. True, they were recorded on the early acoustic machines in which the artists had to shout into a tin horn, but the advent of radio also brought improvements into the field of phonograph recordings and made possible the electrical recording or transcription. Today all phonograph, as well as special records for radio, are made by electrical means. It is common practice to make a recording of a radio show and play it back over the air at a more suitable time; this is called a delayed broadcast. Not so long ago the New York studios of the national radio networks used to have two performances of each of their most popular shows because the time on the west coast was three hours behind New York time. This meant that the performers had to do the same thing twice in one evening, and very often the two shows were not exactly similar. Also, they were tired by midnight, or later, when it was time to go on the air again. With the advent of magnetic tape for recording, the repeat performances ceased and a record made at the time of the broadcast is now played over the network lines at the proper time. Sometimes it is made in New York, (or the city where the show originates) sometimes it is made on the other side and the middle of the country as well. Thus, the central standard time region can have its own recording to play at the proper time and so can the other two time zones. This often helps to reduce line costs. So far television has not been in a position exactly paralleling radio since the coaxial and micro-wave relay circuits do not yet link the east and west coasts. There is a parallel in the extension of the cable to St. Louis and Omaha, but because the time difference is not three hours, the disparity is not as great. Most of the kinescope recording systems installed to date, with the exception of that of Paramount, do not provide instant, or even particularly rapid processing, so that only with the Paramount system is it possible to show a film within a few minutes of the time that it was recorded. The requirements for a film recorder are more severe than for a sound recording machine. As we have seen the eye is considerably more critical than the ear and will reject pictures which are not firstclass. In addition to which, it tires much more readily. The conditions under which the film is recorded do not lend themselves to optimum results, and since the recorded picture can never be better than the original, a poor reproduction will obviously be produced if the latter is not of first-class definition and clarity. To start with, we have a maximum of 525 lines per frame; of these about 350 actually are usable in the picture. [Oops! For the US system after 1941-2 it was 483 or 486 lines. He or his copy editor is probably remembering horizontal resolution or the prewar vertical standard.] There is loss of definition in the spreading of the lines [image] in the fluorescent coating of the screen. There is an additional loss of definition in the very slight spreading of silver in the film emulsion. [Another Oops! That should be "spreading of the light because of the silver."] When the film is reproduced, there is another loss in the resolution of the film camera mosaic, [Oops! He means TV film chain camera mosaic. Film cameras do not have a mosaic.] and in the final presentation on the screen of the receiver, a further loss occurs. It would seem to be a miracle that a picture of any kind is obtained! Actually, the losses are so small that they do not amount to much once the film has been recorded, and in fact sometimes the actual process of reproducing the film introduces effects which tend to cancel these losses. [No oops here, although some modern TV engineers will disagree, but if they do, I suspect that they have not seen some of the drop dead gorgeous 35mm kinescopes that made for network use during that era.] Before describing an actual installation, it would be well to consider the problems involved in taking a picture of the television screen. At first sight it might appear that what would be required is a camera focused on the kinescope. Most receivers do have a bright enough picture to enable photographs to be made. But since the complete picture is on the screen for only one-thirtieth of a second (remember thirty frames per second) it means that the maximum lens-opening time [Oops! He means shutter-open time] is only one-thirtieth of a second. This at once introduces a fixed constant into the calculations ; the shutter speed has been determined. Now for the amount of light available. In home receivers, this would easily become a problem and the various designers have solved it in two ways. One system, Paramount's, involves the use of a standard ten-inch tube producing a picture about three by four inches. The other uses a small, five-inch projection tube with a very brilliant blue picture. Each method has advantages and each provides sufficient light. This gives us two figures to work with ; we know the shutter opening and the amount of light available. From this it is possible to determine the size of the lens opening / or T value by taking into account the speed of the emulsion. So we're all set to go or are we? What happens if we shoot at thirty frames a second? The television frame and the camera will be in synchronization because they are running at the same speed, and the program will be properly recorded. (Yes?) Now, what happens when the film is processed and sent to station XXXX-TV in the wilds of Wisconsin? It is placed on the projector and exhibited. But wait a minute, there is something wrong! What is it? Why, the people are all very tired, they move so slowly. Perhaps the projector is running too slowly? No, that's the proper speed. Ah ! The film was made at thirty frames a second and projected at twenty-jour, so of course it is running more slowly than when it was made and the characters have slower actions. (If it had been taken at a slower speed than twenty-four, the action would have been speeded up.) So what can we do? Now we know the problems involved and it is comparatively easy to solve them when you've been told how! The problem boils down to converting thirty television frames to twenty-four film frames each second just the opposite of converting twenty-four frames of film to thirty frames of television when we are exhibiting films. In the latter case the conversion [from 24 frames per second to 60 fields (not frames)per second] was made by the simple trick of exposing one frame twice and the next one three times. In this case it is not quite as simple, but the technique is very similar. There is one other factor which has to be considered, and this is most important; it is the sound which accompanies the program being recorded. Either of the two methods of sound recording already described may be used: that is, double or single system. So far, it seems that the single system in which the sound is recorded on the same film as the picture is more popular. Provided that the quality can be maintained, and there is a way in which it can be, there is no objection to this method. Three paragraphs ago it was pointed out that merely speeding up the camera would not produce satisfactory results because the actions would be too slow when the picture was projected. Also, the sound would, of course, be affected and reproduce in a low pitch. But even if the projectors in television stations were speeded up so that a film made at thirty frames per second could be used, the problem would be nowhere near solved since then the projectors would not be usable with ordinary theatre film and this makes up the bulk of the television programs at most stations. It would also restrict the use of kinescope recordings for audition purposes. Thus it is seen that the normal figures of twenty-four and thirty frames must be retained and the conversion performed during the action of recording on the film. [FYI Comment, no error: To the best of my knowledge 30 frame per second film (Eastman color negative) shooting was not commonly used in the US until the late 1970's through the 1980's where the editing and viewing were done on video, and there was never any intention of going back to film. This improved the image quality and made film look more like a live TV production. Better portable video cameras eliminated the need for this method.] Another aspect which may escape cursory examination is the necessity to retain interlace. If film ran at thirty frames, i.e., there was one exposure for each frame, the flicker reducing effect of interlacing would be lost. A number of different methods have been evolved [to restore the interlace when televised], but they all depend on some form of device, either electronic or mechanical, to shut off the light at certain times, i.e., an electronic or mechanical shutter system. [This is exactly how the 24 to 60 conversion is done, but with 30 fps it is much simpler.] The Eastman Kodak Company has developed equipment for NBC and the Dumont network which does a very satisfactory job. In this case, a mechanical shutter is used. In the author's opinion the electronic shutter requires more work on cathode-ray tube phosphors. No mechanical shutter is used to cut off the light after each desired exposure in this system. Therefore, if the phosphor has a long decay time instead of the light being sharply cut off every time, it will fade and leave a faint blur on the film. Of course, as progress is made in phosphor composition, the situation will improve. [I'm not quite sure of his point here, but electronically extinguishing the beam in the CRT introduces a heck of a lot more problems than it solves. I've never heard of it being done, except for flying spot cameras.] Another requirement is that the magazine be capable of holding enough film for a half-hour show. Most of the cameras used for 16 mm recording hold 1200 feet of film which is sufficient for thirty-three minutes of continuous running. In the event of a show lasting more than this time, it is a simple matter to arrange to switch to another machine at the end of the first reel in the same way that a motion picture projector is switched during projection. But even now it is too soon to discuss the methods used, for there are two more small matters to consider. First, due to the small amount of time available for film pull-down, it is necessary for it to be moved very rapidly. This means that the wear on the film is higher, and it also calls for greater precision in the mechanical details of the movement. Secondly, if 1200 feet of film are used for one take rewinding it presents a slight headache. The size of a roll of this length is about ten and one half inches in diameter. Yet when rewinding commences, the core or the spool center is only approximately two inches. It is at once obvious that the peripheral speed will increase as the film winds onto the take-up due to the unavoidable increase in diameter. Some form of slipping clutch is therefore required to provide a varying speed from start to end. [ ??? These clutches for film cameras were invented in the 1890's. The early ones were simply slipping belts. I fail to understand his point, unless he is talking about the continuous real-time film processors that Paramount used, and even then it was very old technology.] Practical Conversion. Since a field is 1/60 of a second, it follows that half a frame is 1/120, or 72 if expressed in terms of shutter action or blanking. A shutter which is open for 288 or 1/30 of a second is not hard to design; this leaves half a field, or 72, for closed time. If the sequence commences with the shutter open and an odd field is followed by an even, both will be recorded on the first film frame. Then the shutter closes for 1/120 of a second and the first half of the next odd field is lost, the whole of the even field is recorded and also half the following odd field (two film frames). The shutter then removes half of this odd field and records a full even field plus half an odd field before it closes again (three film frames). The fourth film frame records in this order half an even field, a whole odd field, and half an even field the second half being lost under the shutter. Now the whole cycle repeats itself. [Modern film recorders do not lose any frames.] It will be found that four film frames have accounted for five television frames, this is a ratio of 4 : 5 or 24 : 30. Of course, in the process, something had to be removed and so it is that part of each frame is lost; however, owing to the overlap, this is not noticed by the viewers provided due precautions are taken. In some of the poorer film recordings, viewers will have noticed a narrow light or dark bar which moves up or down on the screen. This is known as a shutter bar or banding. It is caused by lack of synchronization between the sync generator in the studio and the recording camera. Since this is effectively joining the point in each frame where the old and new picture contents begin and end, it is generally known as a splice. This should not be confused with a film splice in which a physical joining between two pieces of film stock is made. It is one of the features of the system that a splice appears unavoidably in each frame. [He means each 'scene change', not each 'frame'. Better video switching equipment - the electronics delayed the camera change up to 1/30th of a second so the switch happened during the vertical black bar, quickly eliminated this problem. I think this defect was very rare even by 1948.] Therefore, since it cannot be removed, the only thing to do is to minimize it in the best way possible. This means, quite clearly, that the kinescope picture which is being photographed must be perfectly steady with extremely accurate registration; otherwise there will be a change in brightness or content at the splice. This in itself will be sufficient to draw the attention of the viewers to it. From the foregoing, it will be seen that kinescoping is not as simple as it might have appeared at first sight. But the reader of this book will not normally be expected to have much to do with the technical side. However, the sound question has not yet been cleared up, so further discussion is indicated. In the chapter on sound equipment and recording the single system was mentioned as tending to suffer from poorer quality sound as well as difficulty in editing. The latter objection is of no importance since editing is not needed (or should not be) in a recording off the air. The former is of great importance. It was shown that single system's sound troubles arose from the fact that it was necessary to use fast emulsion for picture-taking and slow, fine-grain emulsion for sound recording. Since the two were not completely compatible one had to suffer, and it was sound. Even the mechanical arrangements were against good sound quality in the single system camera since there was always the risk of introducing flutter and wow due to insufficient headway between the picture gate and the sound head. In the kinescope recording equipment designed by the American Broadcasting Company, this trouble has been completely eliminated. This system, which may be said to combine the best features of all those in operation, utilizes a projection type cathode-ray tube with 30,000 volts on the anode. This produces on a five-inch screen an intensely bright, blue picture about two by three inches. In the process, some X-rays are produced which are adequately absorbed by lead glass and other shields; thus there is no risk to personnel. This picture is focused onto the film in a special Wall camera. [The Wall camera was manufactured by the Doyle & Wall machine shop in Syracuse, NY and became the first sound-on-film news camera used by Fox Newsreel. It was designed by Theodore Case in Auburn, NY. See: http://cayuganet.org/cayugamuseum/ If you are ever near Auburn, the Case sound lab, next to the museum, is a nice place to visit.] Below this camera is a Maurer sound recorder; each is driven by a different motor in fact, four are used in all. The sound gate is eighty-two frames ahead of the picture instead of the usual twenty-six. This means that there is no chance of wow or flutter from the intermittent since all irregular movements have been eliminated long before the film reaches this point. [This was overkill and introduced printing problems described below. J. A. Maurer soon redesigned the recorder to eliminated the problem.] Of course the problem is, what happens to the projector standards mentioned previously when it was stated that the film from a recorder must be standard? The film is developed as a negative, complete with sound, then the sound is re-recorded on tape, disc, or another film. A print is made (positive) and the sound added in synchronization the usual twenty-six frames ahead. Thus a normal release print is obtained with first-class sound and picture quality. The film used in the recording system is sound positive. [Oops! I'm not aware of any positive stock used for this purpose since the first sound tracks of the late 1920's and early 1930's, but instead the film lab used a special sound recording negative stock. We certainly used this until we switched to Eastman color negative for the picture and still used sound recording negative for the track in a separate recorder.] This has a slow emulsion which is blue-sensitive and has an exceedingly fine grain. The light from the recording lamp is, of course, ample for sound work, and the blue light from the projection kinescope is not only very bright but suited to the spectral characteristics of the film so that a reasonably small aperture can be used with consequent better focus. Another and not inconsiderable reason for the use of sound positive stock is its low cost. One thousand feet of it cost about $ 15 or less in quantity. Thus the only costs for a kinescoped show are wages, overhead, and film. Compare this with a repeat show with all the extra costs for talent and studio technicians as well as stage hands, etc. The film costs might be as high as $50 for a half-hour show plus overhead but this is nothing compared with live repeat costs. The program-in-a-can feature is also extremely convenient. As has already been shown, the coaxial network and micro-wave relays have not yet covered the country, and it will be a long time before all the smaller towns receive service. Even today, it is impossible to get outside programs in Los Angeles, the home of movies, or San Francisco. Everything not locally produced has to come in on film. Similarly, in New York, one of the first cities in the United States to have regular television programs, it is impossible to present programs from Hollywood by any other means than film recordings. Since the New York audience is pampered by seeing live shows only, either by cable or from local studios and remotes, they do not take too kindly to low-quality recordings from other regions; the difference is too obvious. The other networks, NBC, CBS, and Dumont, make use of various methods of kinescoping, but in all cases the principle is the same with individual variations. Some of these operations use double system, however, in preference to the single. Some use a ten-inch screen for recording with a whiter picture color. [If you wonder why anyone would do the below, think PAY PER VIEW. Yup, pay for view before practical video projectors were invented.] The Paramount intermediate film system has already been mentioned, but it may not be realized just how specialized a kinescope system it really is. It is possible to record, develop, and project a picture within sixty seconds, and the latest equipment, designed primarily for theatre work, can do it in fifteen seconds. This system uses 35 mm film exclusively. For the slower, sixty second operation ordinary nitrate film is used, but for the high speed, high-drying temperature system acetate base has to be used to overcome the fire hazard. In this apparatus a magazine of 12,000 * feet capacity provides sufficient film for a two-hour program. Film from the magazine runs through special lightproof guides to the camera and from there to a series of developing, fixing, and washing baths. After this it is dried and either wound onto a reel or conveyed below to the projection booth and into a projector if it is to be used for large screen projection. An Akely camera is used in this system. [Akely was a custom camera maker.] [ * Comment on 1200 feet: This was double the length and weight of the monster reels used during the 3D era in the 1950's and those caused many back injuries to the projectionist. This big of a reel would take two men to lift, and prior to exposure the reel would have to be handled in complete darkness.] It would seem that until the quality of the recorded image improves, kinescoping has much more appeal to the isolated station than to the station which is on the coaxial line or micro-wave relay link. General reports at hand state that this is indeed the case, and while the multi-station markets are not making much use of them, single-station, off-coaxial-cable towns find kinescoping not only a god-send but also very popular for they enable these stations to provide the cream of the four networks' service as well as easing some of the financial load. Until some practical method of recording live action directly on film has been developed, kinescoping appears to have a very important place in the television circle; and even when, and if, direct filming is possible the kinescope recording will still be valuable. Once the union problems are cleared up, its usefulness will increase considerably. [End of chapter] I hope this answers your questions. James. Last edited by earlyfilm; 12-29-2011 at 09:11 PM.
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#13
12-29-2011, 09:48 PM
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Thanks!
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#14
12-30-2011, 02:02 AM
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I think James may have misinterpreted something that Battison wrote, although it is sloppily written: when he says that there are only about 350 scan lines that are usable, he might be referring to the utilization ratio, which determines the effective vertical resolution. The NTSC standard specifies 525 scan lines, but this number includes the lines during the vertical blanking interval: a few at the bottom just before the flyback begins, during the flyback itself, and at the top of the next field while waiting for the ringing effect caused by voltage overshoot to settle down. In this you lose roughly 40 scan lines per frame, leaving 486 lines in the visible raster.
However, the effective vertical resolution is considerably fewer, since it depends where the contours of a scanned object are in relation to the scan line. Consider the following: let's suppose that you have a column of alternately black and white boxes, the height of each being exactly the same as the width of the scan line. If each box is positioned directly under a scan line, then you will get a column of 486 alternately black and white boxes, one per scan line. But let's suppose that each box straddles a scan line. The voltage of the camera signal will be the average of 100% (black) and 0% (white) or 50% grey, and since every scan line has the same property it would be impossible to tell where one box ends and the other begins, or in other words, you wouldn't get a column of boxes on the TV screen but a vertical grey strip, and in this case the vertical resolution would be zero. Both these cases are completely artificial, but the principal is valid nonetheless. According to Bernard Grob in Basic Television in a real-world situation, the average vertical resolution would be about 70% of the total number of scan lines available, which works out to 486 X 0.7 = 350. So this is probably what Battison means. One smaller point he makes in an earlier chapter is that the single greatest problem with the use of film on television is the poor quality of the film projectors most TV stations used at the time. Probably because of the high start up costs of a television station--a good quality I/O studio camera might cost around $5,000, which was twice my father's annual pay as a recently-graduated engineer--most stations wanted to cut other costs, and one of the ways that they did that was to buy cheap film projectors--not crappy or defective, but not really professional quality, either. So given this, a station was unlikely to be enthusiastic about purchasing a movie projector that ran at 30 fps, because you couldn't use it for anything except kinescopes, and he cites this as one of the reasons why kinescope films were made at the standard 24fps (35mm) or 16fps (16mm). Battison's bona fides on the front papers would suggest a competent enough author, so perhaps it is just a lot of sloppy writing (and James caught several examples I didn't notice--on Battison's part and slovenly or hurriedly done copy editing. As always, thank you all for your contributions.
__________________
One Ruthie At A Time
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#15
12-30-2011, 06:39 AM
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Quote:
Battison's habbit of jumping from the real to the artificial in the same paragraph, and in a few places like the "350" example, in the same sentence, made this chapter hard to understand even when one was familiar with both disciplines. In most early network TV, the film crew, the studio crew and the engineering crew were represented by different unions and this created a situation where there was little cross training between the different technical people. A quick search only found one other book by Battison, and that was 20 years later. "AM broadcast transmitters", by John H. Battison and Edward M. Noll which was published by the International Correspondence Schools, of Scranton, PA. James
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