Protecting Your Vision Part I The Frame Leader Mark Woods Director of Photography

Since I wrote my format article on Super 35 mm, I was approached to discuss some of the common formats used in TV today. This includes Super 35mm TV, Regular TV, and the various ways to shoot 4x3 (1.33:1) and “protect” 16x9 (1.78:1). Any format with “Super” in front of it describes a full aperture format. This means that there is no space left on the negative for the sound track since the lens is optically centered and records the image on the camera’s full aperture. This format is used in Super 35mm Anamorphic, which I’ve already discussed, optical effects, and in TV where there is no theatrical release anticipated. If a release print is stuck from a TV show shot in Super 35mm, the image must be reduced and repositioned on the negative prior to making the release print. The image will most likely be recomposed to the “new” format for projection. Four perf Super TV is fairly common in TV commercials and in TV shows. Three perf is also common in TV. This format more closely matches 16x9 than 4 perf. It also saves the producer 25% in film stock with very little loss in image quality while allowing 33% more running time per magazine. A 2000 foot film load is 28 minutes of film time. Super 16mm uses the whole image area of regular 16mm plus the soundtrack and perf area. Therefore, Super 16mm can only be filmed on single perf stock. By the way, in terms of image area, if 35mm 4 perf equals 100%, 35mm 3 perf is 92%, while Super 16mm is 375% less than 3 perf and 404% less than 4 perf. There is no doubt that the camera team must be more careful when filming in Super 16mm, and the exposures should be filmed with very tight tolerances.

The four most used formats in TV today when shooting 4x3 and “protecting” for 16x9 are 4 perf Super TV Common Top and Bottom, 3 perf Super TV Common Top and Bottom, the Paramount format of Super TV with Common Sides, and Super 16. Super 16mm is generally used over Regular 16mm since the larger 1.66:1 image area on the negative more closely fits 16x9 format than the 1.33:1 of regular 16mm. In reality, the choice of the format is often made by the producers in conjunction with the post production supervisor. If you look at the ground glass drawings Tak at Panavision kindly provided, you will see the obvious, when shooting 4x3 and protecting for 16x9 part of the image is either lost or added. In all of the formats, except the Paramount format, the show is filmed in 4x3 and the 16x9 “sides” are protected for future HD presentation. The Paramount format has common sides and top, but loses a portion of the bottom of the composition when the image is presented in 16x9. All of these formats have supporters and detractors and present compositional challenges for the operators. What Directors of Photography need to be aware of is how to indicate to the post-production house, and future post production facilities, what the show’s format was when it was filmed. The communication to day with the post-production supervisor isn’t enough since the archival aspects of film approaches 100 years (the half-life of videotape is 15 years).

When filming for TV, the ground glass should have TV Transmitted and TV Safe indicated. Many Directors of Photography, or their operators, only have TV Transmitted indicated on their ground glass, and use that indicator for all of their framing. At this point, they apparently have no problems. They may mistakenly assume that they are using more of the negative for television transmission and this will provide a better image. The Directors of Photography using the Paramount format have TV Safe indicated on the ground glass since this format uses common sides and top and the lack of head room would be noticed immediately. In the other formats, including Super16mm, the post production facilities can make 4x3 images work using the TV Transmitted lines on the ground glass. This is a simple matter of reducing the image slightly during telecine, or using the remaining part of the image above and below the transmitted area. This doesn’t seem like a big deal, and for now it isn’t. The problem is in the future when the show is presented in 16x9. If the image is reduced to make up for the fact that the show was shot using the TV Transmitted lines for framing, there is a good likelihood that part, or all, of the image on the sides will be lost. The same is true if part of the image is used from above and below the TV transmitted lines, the ratio of width to height has been changed, and something will be lost. In other words, if the image uses more of the height, it must have more width. Of course this isn’t possible since the edges of the 16x9 frame is set and cannot be expanded. You can imagine how a rich and full frame will become a mess in this environment. The Director of Photography needs to understand what TV Transmitted and TV Safe indicate and to communicate it to the operators.

Take a moment to look at the drawings for Ground Glasses. All of them indicate the Full Aperture, the TV Transmitted area, and the TV Safe area. Again, it may appear that you could use the TV Transmitted area for framing because modern TVs transmit the whole image, but that would also be a mistake. The TV manufactures have at least 10% tolerance in the electronics of their receivers. This tolerance is the difference between TV Transmitted and TV Safe. The part of the image that is lost could be on any side, or all sides of the image. You can quickly understand why the use of the TV Transmitted for framing is a problem. Again, I know of Directors of Photography who do use the TV Transmitted indicators for their frame line and have no problems now. But look again at the Ground Glass Drawings for the common top and common bottom formats particularly the 4 Perf format. Note the image area above and below the 4x3 TV Transmitted lines. It would appear that this is wasted negative and should be used in filming the show. If the show is only going to be viewed in 4x3, that would be correct. Again, the problem arises on the sides of 16x9. If the TV Transmitted lines are used in framing for 4x3, there is little or no information left for 16x9 sides. It is this future application we are being asked to protect. The more height used, the more width is necessary.

In researching this article, I visited a set that uses 3 perf pedestal cameras. Panavision has modified their Panaflex cameras with an optical block that splits the image, allowing 70% to expose the film and 30% to be used by the video tap. There is no eyepiece on the camera. There also isn’t a “ground glass” in the sense we think of one. But a scribed glass blue filter indicating TV Transmitted and TV Safe is inserted in the optical path, and works with the video tap in the same manner as a ground glass works with an eyepiece. The lines are calibrated to the camera in the same way the ground glass is in a normal camera. In that sense, the lines are as accurate as ground glasses are on a camera with an eyepiece, only the method of achieving the indicator lines is different. In cameras where these lines are electronically indicated there probably would be a problem, but I’m not aware of a film camera that uses an electronic indicator as opposed to an optical/mechanical indicator. On multi-camera film shoots where the operator views the scene through the eyepiece, there shouldn’t be any problem with the ground glasses being different if the cameras are all from a reputable rental house, like Panavision, Clairmont, Otto, etc. The other stipulation is that all the ground glasses have the same indications. In Super 35mm Anamorphic, the different frame indicators can be scribed in different locations within the full aperture. In multi-camera productions, the Director of Photography needs to have all the cameras’ ground glasses match in format and what is indicated on the ground glass. Minimally, this would be TV Transmitted and TV Safe. There should be no exceptions.

From what I’ve said, you can see why shooting a frame leader is important. The information on the frame leader establishes all edges of the operator’s compositions. Without this information, the electronic post-production facilities can’t accurately position the image for 4x3 TV, much less 16x9 HDTV. The headroom will never be what the operator composed, the sides will have either too much or too little information. The work of the Director of Photography is compromised beyond the “shoot for 4x3 and protect for 16x9.” I’ve included a frame chart from Panavision that indicates 4x3 (1.33) TV Safe and 16x9 (1.78) Protected. One of the issues I’ve heard from a number of post-production houses is the desire to use the common top and common bottom while protecting the sides. The more accurate approach is to use a common top and bottom TV Safe while protecting the sides for 16x9 TV Safe. The common top and bottom TV Safe is a more accurate indicator of what the final viewer sees, and better insures the compositions will remain true to what the Director of Photography, with the camera operators, actually filmed.

The first approach to filming a frame leader is to find an accurate frame leader like the one published here in International Photographer. If the frame leader is spray mounted to a piece of show card it will simplify filming and make it easier to keep in good shape. By the way, don’t enlarge or reduce the chart, since photocopying tends to change the height to width ratio. When filming the chart, it must be parallel to the film plane and perpendicular to the optical axis. Use a 50mm lens for 35mm format (a 25mm lens for 16mm). The indicator lines on the chart need to be lined up with the correct indicator lines on the ground glass. For example, the TV Safe indicators on the ground glass are placed over the TV Safe lines on the chart. The TV Transmitted lines on the chart are lined up with the TV Transmitted lines on the ground glass. Once this is done, the framing chart is exposed and after the film is processed, the transfer house should be given the framing leader with the instructions that these lines are accurate to the ground glass on the camera, and should be used for all transfers for the show. Another way to film a frame leader is to use the camera’s ground glass with the camera working as a projector. In the early days of film, cameras often did double duty as cameras, then after the film was processed, the camera worked as the projector. To do this, my 1st AC, Mike Bratkowski, puts a piece of foam core about 4 feet in front of the lens, parallel to the film plane. He then tilts up the eyepiece and focuses and centers a Tweenie, or other small bright light source into the eyepiece. The light travels though the eyepiece optics, through the ground glass, reflects off the mirror, and then he focuses the ground glass’s image through the 50mm lens onto the foam core. In a dim room, the image is clear and absolutely accurate to the ground glass in the camera. He then uses ½” paper tape to indicate the different lines and clearly labels, which each line indicates. Once he has done all this, he then resets the lights to now film the chart (with no hot spots). We’ve used this method for a number of years with great results. The line indicators on the ground glass match the frame leader we turn into the lab and the post production supervisor.

I really can’t emphasize how important it is to film an accurate frame leader for the transfer house indicating where TV Safe is on the film. Since there is no “ground glass” or a standard image size for the telecine machines, the frame leader works as the telecine’s ground glass that matches the camera’s ground glass. This can be a one to one relationship that insures correct framing and positioning of the image. Once the Director of Photography has shot a framing leader and given to the transfer house, it is important for him to communicate with the operator what each line on the ground glass indicates, and the importance of each. If only one indication is desired for each format, that line indicator should be TV Safe. The frame leader should be shot with the TV Safe lines coinciding with the TV Safe lines on the ground glass. In this situation, the TV Transmitted lines could be on the frame leader while not being on the ground glass. The important aspect on all of this is to understand the ground glass line indicators, and to use them accurately.

April, 1999

next >

< previous