> God, I never thought I'd end up defending video, but there are just > some pretty basic facts that are getting glossed over. I agree, I didn't want to go into an detailed technical description of the specifications of video and film standards. > First of all, resolution is measured in *horizontal* lines, not > horizontal and vertical. Yes, in broadcast the resolution is measured in horizontal lines, however I was thinking of an example which I saw last May where the resolution was measured by a pixel count of a specially enhanced HDTV image on a computer generated display. At the last International Council of Archives Joint Technical Symposium the BBC and the East German Film Archives cooperated in an experiment to see if HDTV and digital signal processing could be used in the restoration of 35mm film. The Germans used traditional photographic techiques on a reel of a 1942 feature shot in colour. The BBC transfered the negative to digital HDTV tape and used DSP to restore the film. We had an opportunity to examine both the finished products. It was instantly apparent which was the video and which was the film. The representatives from Ampex, Sony, BASF, and the television engineers all agreed that even the best HDTV efforts in the labs could not compete with the quality of film. > Second, 1250 line is one of many HDTV formats, and > there are some with higher and some with > lower resolution. The only HDTV standard with production equipment > available is an 1125 line system. I am aware of some 15 different HDTV systems in development, The system the BBC used in the experiment was a 1250 line system based on a PAL compatible standard. Both the BBC and German Television are working towards this type of standard for future production. I know the the HDTV programs shot by the CBC and the Japanese MUSE system are 1125 lines due to the NTSC background of their existing systems. As far as I am aware the only country with a regularly operating HDTV system is Japan. Although programs shot with HDTV equipment have been shown, in NTSC form on Canadian and US television. The Europeans have also experimented with HDTV images broadcast in both SECAM and PAL. The quality of the images as received in the consumers homes was only marginally better than the normal broadcast image due to the limitations of the existing broadcast chain. > Third, Kodak-conducted tests indicate that the > resolution of 35MM 5247 negative is comparable to a scanned image of > 2330 lines (Mathias and Patterson, 231). I have seen the Kodak test results and the images which they used to come to their conclusions. They used a series of degraded 35mm transparencies to simulate the scan lines of a single frame. The judgements of quality were entirely subjective and were based on a still image. The 2330 line image was the image that came closest to revealing all the image. I found it interesting to examine the powerplant in the background through the series as the number of smokestacks changed as the resolution increased. At 1125 line resolution there was still one smokestack missing. > NHK tests indicate that the human eye cannot perceive a difference > in resolution above 1600 lines (231)--under the > conditions of the test, which means super-ideal. Again the NHK tests were entirely subjective and based on a television sized image of about 1 metre width. When you scale up the image a 1600 line image no longer is sharp enough. Under home viewing conditions a 1600 line image is probably "good enough" for most viewers. I suppose that I can't be classified as a typical viewer. > Still, the question remains as to whether the technology > reaches a certain point where its simply overkill. I firmly believe that different technologies have their niches in which they are best suited. Current broadcast technology produces, in my opinion, a marginally adequate image. HDTV, as currently proposed, is considerably better. But HDTV does not come close to existing film, regardless of its aspect ratio. The signal information is just not there and will require at least one more generation of development beyond HDTV to adequately approach the density of information a film can provide. As to the question of overkill, that really depends on the applications to which the technology is put. I don't think the afternoon soaps require HDTV let alone film quality, however, a photomicrographic project will almost certainly require film. > I agree there are stylistic differences between video and film, but the > implication here is that they are somehow innate to the technology. > These differences are culturally specific. While they have a context > arising out of certain technological factors, there is nothing about > the technology itself that dictates television to be a close-up medium, > or film to be panoramic one. > We have ascribed these differences to the media, without recognizing > our own expectations, by simply remembering what we have already > seen and where we have seen it. > > According to your argument, a person trained in video could not shoot > in HDTV, since the aspect ratio of HDTV is 5:2. > Here are really two issues here; one involving composition that > doesn't have anything to do with the resolution of video and the > resolution of film, > and the resolution of a 70MM print like Lawrence of Arabia. Under > current standards, video would not compare favorably to such a print. > But that doesn't mean that a similar effect can't be created with a > similar aspect ratio. > I did not mean to imply that a person trained in conventional video could not shoot in a widescreen format. I was pointing out that people who have tried using video composition techniques for the "big screen" have generally not been successful. Partly due to the scale of the image and partly due to the limitations that a video producer must live with due to the technology of video. This does not mean they cannot learn. LAWRENCE OF ARABIA is a good example to use to compare the effect of resolution on an image. Compare the VHS, Videodisc and film versions of the scene where Lawrence is at the waterhole and he sees a small figure approaching from the horizon. The figure just isn't there for most of the scene on video. Of course, as you point out, current video technology can't compete. Mark Ritchie | Tel: (519) 888-4070 Media Librarian | Fax: (519) 888-6197 Audio-Visual Centre | University of Waterloo | NetNorth: [log in to unmask] --------